Moss-covered wall

We visited Iceland in early August. Reykjavik has many gardens, even a quite interesting botanical garden, but the highlight of the trip, floristically speaking, may have been a moss-covered wall fronting the city hall.

But that description of this unique "vertical garden" is far too bland. It's much more than that - visually, it's an arresting structure, long and green, at least in summer, full of texture and color, both a beautiful object and a powerful symbol. It is a wall of allusion, with symbolic references to multiple aspects of Icelandic ecology, culture and history, evoking the moss-covered lava fields surrounding the city, the old turf houses with "green" roofs the rural Icelanders lived in for centuries (consider the similarities to the turf-roofed house below). It pays tribute to the maritime heritage of the country, which depends for most of its wealth on the sea (reflected in the portholes in the wall), and is a fitting reminder of the location of the city hall at one end of the Tornin, a small jewel-like lake in the center of the city. Possibly other references beyond my knowledge are present there.



The wall is long, fronting the entire length of the building, with a large pool at its foot. It appeared to be kept moist by a spray of water from along the top (though Iceland's climate is so damp, it seems unlikely the mechanical watering feature would be needed all the time).



This looks like an exemplary model of sustainable design, using a monoculture of native mosses, as well as what appear to be a few self-seeded grasses and forbs, growing in a matrix of natural lava rock. I haven't been able to find any reliable documentation on the design of the wall, its maintenance or its history. If you know anything about it, please post a comment or send me an email.



The portholes are a nice feature of the design, adding considerable visual interest, especially from a distance. They serve as focal points, drawing your attention toward the wall, where you can appreciate the mosses and other flora close up.



The last photo shows one end of the city hall opening over the lake. You can see the building structure is made of two similar halves with arched roofs. In the center, between the two halves, you can make out the end of the moss-covered wall. It looks very dark because the day was rainy, and the building casts the wall into shadow.

Sounds of the Creek

Lokatong Creek is about a quarter mile behind the house. You can hear its soft, muffled roar through the trees almost any time of year, except when it's frozen or in drought. The rain is starting now, after several days of warm weather - so warm I've seen forsythia and rhododendron starting to bloom. Here is a view of the creek from early November, as its flow began to slaken after heavy rains.

Rosemont Valley

These photos of the Rosemont Valley show an almost idyllic landscape rooted in two centuries of agricultural history. My Rosemont Garden was designed, not to duplicate the look of the valley, but to complement its aesthetic and emotional character - to suit the "genius of the place" in Alexander Pope's words.

The Garden at Federal Twist is only four miles away as the crow flies, but it's a world apart, a closed setting in the woods, with a tree-ringed circle of sky, protected by the surrounding forest, not open, windy and bright like the Valley. I'm slowly working out the nature of the new garden, but I'll remember it's still only four miles from Rosemont, and try to preserve something of that memory.


(Click on the photos to get a better sense of the scale of the landscape.)

Seedheads in the garden

Noel Kingsbury's Seedheads in the garden is written for gardeners who haven't yet become converts to the beauty of plants in the fullness of autumn, or the opportunities they provide for continuing interest - and moments of wonder - during their death and decay in winter. The new book lacks the poetry of Designing with Plants (written with Piet Oudolf) and the erudition of Planting Design: Gardens in Time and Space (also with Oudolf), but it carries forward a useful idea. I hope it will reach a wider audience interested in sustainable garden design.

I'm still in the early stages of planting the new garden on Federal Twist Road, but patterns are beginning to emerge, and a collection of seedheads is in the future. Rudbeckia maxima has proven to be deer resistant through the green season, and its large dark brown seedheads (above and right) contrast well with grasses. The grasses, too, offer an even longer lasting, though smaller and more delicate tracery. Miscanthus purpurescens, leaning in the wind in the photo below, is full of drama, while Panicum virgatum 'Cloud Nine' emulates its tranquil cloud-like name. It too can be blown wildly about and lean to the ground in the wind - though the lower photo was taken on a still day - and surprisingly returns upright when the weather settles.

Miscanthus purpurescens











Panicum virgatum 'Cloud Nine'

I intended to collect teasel (Dipsacus fullonum) seed in the wild this fall, but never got around to it. I planted it in my garden in Rosemont, where it was especially beautiful in summer, and added interesting structure in winter. Note that it requires careful control, seeding with wild abandon. The last photo shows it in mid-summer.

Dipsacus fullonum

The Vermont Gardener

Being a fan of slow gardening and fuzzy gardening (gardening in the context of the wider landscape and, well, the universe, I guess), I recommend The Vermont Gardener.

Chance

An old weeping cherry, planted when the house was built in 1965, frames simple Miscanthus sinensis 'Silberfeder' on a breezy October morning. Unintended movement of the camera exaggerates the light and movement. Just such accidents, serendipities, are the life of a garden, and guide its design. I was at a meeting yesterday in Crystal City, an office development in Arlington, Virginia, jammed up beside Washington National Airport. The Crystal City plantings were quite obviously expensive, and very attractive in an office park kind of way, but that neat, overly manicured style isn't my idea of a garden. There's too much of the cookie cutter architect's vision about it. Better a little mess, accident, and chance, or at least a suggestion of something not entirely within our control. Ironically, those Crystal City plantings are only about a half mile from Oehme & Van Sweden's thrilling plantings at National Airport.

Joe Pye Weed: Eupatorium purpureum subsp. maculatum 'Purple Bush'

A valuable perennial - one of my favorites. It's easy to grow anywhere that's a little damp, and it's rather deer resistant if you can help it get above deer grazing height by hiding it in ornamental grasses or providing early physical protection. Some survive the deer even without your help.

This is a plant with good structure - one of the strongest, easily standing up to heavy snow in my Delaware River Valley garden - beautiful umbelliferous flower heads, and distinctive foliage that makes a strong geometric statement. Though it grows in clumps, it's a good competitor and does very well in a naturalistic garden setting, easily holding its own among other aggressive plants.

Joe Pye Weed is beautiful throughout the year, providing a pale creamy frosting of color as the buds emerge in early summer, large, sometimes huge, compound flower heads in late summer then, as weather cools, turning dark mahogany in autumn rain, and a leaden brown, almost black, as the weather cools.




It would be a mistake to cut it down in the fall. The darkening color makes it a good foil for the brighter ornamental grasses, and it stands tall, turning into winter sculpture in frosts, freezing rains, and snow.

Click on the photos to see more detail.

Piet Oudolf: planting design for the High Line

For a recent visit to the finished High Line (Part 1), click here.

Since this post in 2006, the first part of the High Line has been completed with
great success. I visited last night (Aug. 24, 2009) and encountered crowds of visitors.
To find several additional posts on the High Line as it was being constructed and planted,
type "High Line" in the search box at the top of this blog.

The High Line, an abandoned elevated rail line on the West Side of Manhattan, is being converted into a linear park and trail. For the first time in New York City, this innovative park will introduce Piet Oudolf's work on a large scale. While his plantings for the Memorial Gardens in Battery Park are a successful and attractive feature of Manhattan's southern tip, the High Line is a much more ambitious and challenging project that promises to attract widespread attention.

The High Line linear park concept was inspired by the natural growth of vegetation on the elevated line after it was abandoned in the late 1970s. As urban wilderness overflowed the elevated concrete, steel and riveted structure, it developed quite a following among urban naturalists and seekers after the unusual and novel. It was just this wildness, the sense of wilderness within one of the largest cities on earth, that captured the imaginations of so many.


A group named the Friends of the High Line, the City of New York, and numerous supporters have finally succeeded in creating a vision, and finding funding, for the new linear park, which will run from the area of Penn Station south through Chelsea, into the old meatpacking district at 14th Street, a former derelict area that has become quite trendy.


The diverse, opportunistic flora that insinuates itself in the abandoned interstices of cities is an emblem of the power of plant life to recover (literally, re-cover), reclaim, and restore waste areas - as well as a symbol suggesting a lost, abandoned world of the future. The High Line website takes an upbeat and practical view of the project: "Preliminary designs focus special attention on integrating planting areas with planked public walkways, creating a diverse series of interactions between the High Line, its users, and the spontaneous landscapes that come to inhabit man-made structures over the course of time."

The design team selected for the project is Field Operations and Diller Scofidio + Renfro, with Piet Oudolf as the planting designer. Design is now under way and necessary demolition work has already begun. Piet Oudolf presented examples of his recent design work, as well as preliminary concepts for High Line planting design, last April at a theatre in Chelsea. If you know Oudolf’s work, you will find this to be a trove of this master plantsman’s sensuous photography and cutting edge garden designs. Go to the Piet Oudolf and the High Line link below to see the five part presentation. You will need Adobe Reader, which you can download from the site if you don’t already have it. For more on the history of the High Line and selection of the design team, see the New York Architecture Images link.



























Piet Oudolf and the Highline

New York Architecture Images

Aconitum carmichaelii and signs of life vanished

At the end of October, I've found three colonies of Aconitum carmichaelii in bloom on the roadside within two miles of our home. Two seem to have been planted many years ago as ornamentals on the grounds of an impressive prerevolutionary stone house on Strimples Mill Road. The third is on Federal Twist Road, apparently near the location of an old homestead, now vanished.

Surviving non-native plants are signs of former habitation throughout this area, and set the mind to thinking of the unknowable history that has passed here - the Lenape people, who must have used the nearby Lockatong Creek as a resource for living and hunted these woods, the ancient stone rows that show this inhospitable land must once have been farmed, though with great difficulty, the wives, almost certainly they were wives, who planted wisteria and monkshood and who knows what else?

Pycnanthemum muticum - a short history of an affair with a smelly plant

I've seen Pycnanthemum muticum for over two years at Paxson Hill Farm, a small specialty nursery just across the Delaware in Bucks County. It was always swarming with bees and other insects when in bloom, and I was definitely interested. But I never bought it.

Then I saw it for sale on the website of Bluestem Nursery in British Columbia, which advertises it among a selection of perennials called 'Wolfgang's Picks' (Wolfgang Oehme of Oehme and Van Sweden). I did order a substantial number a year-and-a-half ago, but only about three survived the transit. Looking at these now mature plants I can see that the silvered texture of a mass in bloom could be a pretty, and deer-proof, sight.

Michael King's Perennial Garden Design, which I highly recommend for its valuable information on such little known (in the U.S.), innovative planting designers as Heiner Luz of Germany, has two photographs that convinced me I needed to give this extraordinarily aromatic plant a try on a big scale. One photograph is of a large group of mixed pycnantheum and Petasites japonicus, backed by a wall of Miscanthus s. 'Silberfeder', designed by the Oehme and Van Sweden firm. The other was of a mass planting of pycnantheum alone.

At Bowmans Hill Wildflower Preserve, I saw the plant in its natural setting, growing in tight communities in the open grass meadow (the photos above and below were taken at Bowman's Hill).

So I bought all the plants available at Paxson Hill Farm (only six or seven). In August, after Jessie and Brian's wedding, I traveled further upstate (New York) to Loomis Creek Nursery (you may have seen it featured in the lavish British magazine Gardens Illustrated a few months ago), where I had seen several gallon pots of Pycnanthemum muticum earlier in the summer. I bought 20. Later I found 10 more at Bowman's Hill.

They're all planted now, and I'm hoping for a rapid spread across my wet clay this winter. I know I have to wait a couple of years, at least, to get the effect I'm seeking. In addition to visual interest and a neat addition to wildlife habitat, I do hope the odor and taste of this plant will send deer fleeing. (I should know better).

I need about 30 more plants.

Autumn light: confirmation

A group of Calamagrostis acutiflora 'Karl Foerster', Miscanthus purpurescens, Panicum virgatum 'Dallas Blues', and Panicum v. 'Shenandoah'.

Following several days of intermittent, heavy rain, the early morning sun is backlighting a group of grasses in my Federal Twist garden, confirming my plans to add other groupings of grasses that echo one another in an apparently random, but complementary, way.

The forms and colors of each grass stand out against the dark backdrop of the woods, and the backlighting brings out the character of each. The fluffy, white plumes of Miscanthus purpurescens add an especially natural feel to the planting, almost like white smoke, and contrast with the more formal calamagrostis. The Panicum 'Dallas Blues' has begun its turn toward pale yellow, which I remember will darken to a rich russet throughout winter.

We are nearing the end of the second year of planting, which has been slowed by need to control invasive weeds - the worst is a smothering blanket of Japanese stilt grass (Microstegium vimineum), with enough poison ivy and multiflora rose to cause additional trouble - and by my budget. So as winter nears, planning for next year's planting begins (I should say "continues").

Gardening blogs

This weekend I found a gardening blog I can really resonate to, published by a Yvonne Cunnington in Ontario. If you haven't seen it, check out the Country gardener.

Viburnum dilatatum

Driving along Rosemont-Raven Rock Road on Sunday, I had to stomp on the brakes and back up (almost into a ditch) to better see two colonies of Viburnum dilatatum. These are on both sides of the road near the Westcott Nature Preserve. Nice berries.




For info go here

Blogging help

I've been at this only a few months and continue to have questions about blogging, how to make it easier, how to make contact with others who have similar interests. Here's a link to Amy Stewart's help spot.

Dirt: Don't Get Dirt in the Keyboard, and Other Blogging Tips for Gardeners

Is planting Dahlia ‘Bishop of Landaff’ an immoral act?

Look closely through the fog; the red blossoms near the center are Bishop of Landaff.

I support use of native plants in gardening. But I can’t find the visual richness and expressiveness I want with native plants alone. In my Rosemont Garden, and in my evolving garden on Federal Twist Road, I’m using both natives and non-natives. Where I live, that’s taking a political stand.

As preface, I want to say I attend the Native Plants in the Landscape Conference at Millersville University every year, I am a member of the Bowman’s Hill Wildflower Preserve near New Hope, Pennsylvania, a member of the Hunterdon Land Trust Alliance, and a supporter of the Plant Stewardship Index (see June 9 posting below). I believe the American nursery industry should not sell plants known to be highly invasive in local habitats, and it should do much more to educate its own staff as well as its customers in the growth habits and needs of plants.

The native plant movement has accomplished important work — conserving local species, preserving remnants of vanishing habitats, creating awareness of the need to protect threatened natural resources, and educating people about their natural plant heritage. And by insisting on the importance of using plants appropriate to the environment, rather than trying to alter soil and other conditions to grow plants not naturally suited to a given site, the movement has had a pervasive influence on gardening.

The New Perennial Movement — as practiced by Wolfgang Oehme and James Van Sweden in the U.S. and Piet Oudolf, Noel Kingsbury, Henk Gerritsen and many other European and American garden designers too numerous to mention — grew out of a long European tradition. Designers have been riffing on the concept of naturalistic gardening for more than a century, perhaps starting with William Robinson in the 19th century, and probably going back much further. The Germans, in particular, have done very important theoretical and practical work matching plants to habitats and testing their behavior under controlled growing conditions over many decades. This movement toward ecologically appropriate gardening has paralleled the native plant movement, and helped set the trajectory of 21st century gardening (at least for a time). For now, native is good. Constructing a drainage system and replacing your soil so you can grow bearded iris and lavender in a wetland is bad.

But in the face of this success, many native purists appear to be boxing the movement into a dead end. (For more on this subject, read Michael Pollan’s Second Nature, and "The aliens have landed! What are the justifications for 'native only' policies in landscape plantings" by A.E. Kendle and J.E. Rose of Reading University, published in Landscape and Urban Planning 47 (2000).)

By most definitions, a plant is native only if it arrived in its environment without human intervention — on the wind, in bird poop, or in some other way not involving human intervention. In North America, many native plant enthusiasts accept only those plants that preceded the arrival of white Europeans. In the UK, which was pretty much wiped clean of all its native species during the last Ice Age, the Channel delayed the return of many plants that were previously native. Because humans accelerated that process of return in the UK, bringing back plants that had survived the Ice Age in the more favorable environment of the Continent, previously native plants are now defined as non-native invaders. They would have returned by “natural” means, but they didn’t arrive in time.

Now that the earth’s population has reached over 6 billion, it is very difficult to attribute the arrival of a new species in any environment to "natural" causes. Human influence is simply too pervasive. This is a bad situation because it means all the native plants that will ever exist, exist now. The time and geographic doors have been shut. No new plants will be admitted to the native plant lists (at least in the most conservative circles).

Why is this a bad thing? Because the climate is changing, and human culture is changing natural ecosystems, constantly, in huge ways. So the number of native species will necessarily decrease over time, as species after species succumbs to an altered environment. Regardless of current preservation efforts, only a minute fraction of the earth’s land area will actually be preserved in so-called pristine condition.

What is wrong with this picture? Have we defined native plants in a way that will result in extinction of most native species unless we create isolated “plant zoos”? Are we moving toward preservation of native species only in highly artificial preservation environments, on pieces of landscape preserved from human development? But even preserved areas are subject to changing climate.

Perhaps our definitions are wrong. Perhaps the human race is a part of nature after all, and we make a huge mistake to see nature and humankind in eternal opposition. In fact, the landscape the first Europeans found on arrival in North America was not pristine nature, untouched by human activity. Native Americans had been managing the landscape for centuries, and the landscape that was first viewed by European eyes was, in fact, a managed landscape. It just looked different from the one they left on the other side of the Atlantic. The endless prairies in the American Midwest are a notable example. The prairies remained prairies only because fire burned them and buffalo grazed them. The native Americans saw the natural result of fires started by lightening, and started setting fires themselves to revitalize the land for grazing and to prevent growth of trees, which would have turned the prairies into forest within a generation. There are many who now argue that the very idea of a natural environment untouched by human culture is a fiction.

Much of the impetus of the native plant movement stems from fear of the effects of invasive species, many from far away places. But many plants of foreign origin thrive in our environment without becoming a problem — while some natives are quite invasive. The Ohio Department of Natural Resources asks: "Are all exotic plants invasive? No, most non-native plants are not invasive in natural areas. Of the more than 700 non-native plants in Ohio, fewer than 100 are known to truly 'invade' their natural settings." (Ohio DNR link)

Some studies have even demonstrated that exotic species can enrich habitats, adding new genetic material when local plant populations become weakened by inbreeding, and providing useful habitat for a variety of insect life. Not to mention their aesthetic value.

The answer, of course, is knowledge of a plant’s growth habits in different environments, knowledge we have far too little access to.

The United States National Arboretum does not equate non-natives with invasiveness. "In many cases, plants from other parts of the world are welcomed, manageable additions to our gardens. In the worst cases," it adds, "invasive plants like mile-a-minute, purple loosestrife, and kudzu ruthlessly choke out other plant life. Ultimately, invasive plants alter habitats and reduce biodiversity." But the Arboretum does not make the error of equating non-native with invasive. (National Arboretum link)

As climate change continues — and we know it will — after all, we are only in a temporary warm spell between periodic glaciations — what is native or not may come to have less meaning. Better to know what will thrive in the changing environment and creatively adapt to coming changes. I admit there are serious problems with some non-natives. The preserved woodlands surrounding my house are dotted with Berberis, Euonymus alata, and Rosa multiflora. But the threat from these non-native species is very small compared to that of our prolific native deer population, which is the source of the greatest destruction of native flora.

I don’t mean to diminish the importance of preserving native species and local genotypes. We need to do everything we can to preserve the genetic diversity of our biota. Preserving native plant populations, and renewing them, is a part of that. But moving plants from threatened environments to other areas where they will thrive is another part of that story. In some cases, that may mean moving a species across an ocean as climate and growing conditions change in a plant’s native range. Consider the Franklinia alatamaha. If Bartram hadn't collected it and propogated it in his garden in Philadelphia, it would be extinct now.

If we see human ecology as a part of the world’s ecology, for better or for worse, we are in a better position scientifically to manage change. The potential for harm is great, great enough to inspire fear of some terrible consequence of human action. But it does no good to deny the part humans play in nature, and to abandon hope for responsible action. Simply defining nature to exclude the human race is not an answer we can desire. That’s a wish for return to some pre-human paradise.

Last summer I attended an all day workshop on identification of native grasses and carex. As we walked the Bowman’s Hill Wildflower Preserve identifying plants, one woman kept asking, “Is it good, or is it bad?” (Meaning is it of native or non-native origin?) Her question points to how value driven the native plant movement has become. And some ardent adherents believe with an almost religious fervor. I exaggerate, maybe, but in many cases, belief has replaced scientific inquiry.

So was planting Dahlia ‘Bishop of Landaff’ in my country garden in Rosemont a churlish or an immoral act? I don’t think so.

Rosemont recapitulated

The Rosemont Garden (see initial posts way below) received an Honor Award from the Perennial Plant Association at the annual symposium in Montreal in July. Here is a link to photos of the garden.

Rosemont Garden

Sep 3, 2006 - 61 Photos

Cimicifuga racemosa

Just down Federal Twist Road is a community of Cimicifuga racemosa . I first saw it last summer, but this year it appears to have grown to over 20 well sized plants. They're at the front of a property someone is building on, but construction has been stopped for almost a year, and the new house is several hundred feet back. I'm hoping the plants will remain undisturbed.

Compared to the yellow green of the blackberry foliage in the picture below, the cimicifuga appears quite dark. Is this a natural genetic variation?

(I know it's been renamed Actea, but I haven't made that adjustment yet.)

Burn

Speaking of solving the problems my site presents (see posting below), I have succeeded in opening the space and reclaiming some sky. After felling several more trees this spring, I had them cut into logs and stacked to make a naturalistic wall. But a huge amount of debris, mostly branches, was left. Here is one of the burns needed to finish the job.

Am I giving up?

When I started making a garden on Federal Twist Road I understood the limits of the site: wet, heavy clay, thick juniper cover, no view, no space, no sky. And deer.

I'm working through these constraints and, I'm sure, if I continued to search out and test deer-proof plants I could eventually develop a satisfying garden. Ornamental grasses are safe. And 18 months of experience tells me two plants - Asclepias incarnata and Rudbeckia maxima - are keepers. I think Verbena hastata and Pycnanthemum muticum will pass the test. But almost everything else I have tried - including several new willows - have been damaged to various degrees.

I'm ready to give up on living with the deer. I want to grow plants deer eat, and I finally realize the compromises are too dear (sorry!).

I've discussed a deer exclusion with Phil, and he agrees. We probably need over 1,000 linear feet of fencing, and it must be as unobtrusive as possible. And affordable. Now to get some estimates.

Beneath the sea surface

The house is built on an earthen mound, so I see the garden from a height of about 15 feet. At dusk, and in fog, when partially obscured, the garden appears to be under water, perhaps recalling a sea floor of exotic plants and stationary creatures like sea anemones (miscanthus shapes, panicums), odd, almost monstrous forms of Rudbeckia maxima (flower spires emerging from some fantasy castle, or misshapen sea creatures in glaucous greens), sharp water irises. This is an intriguing metaphor to make the best of a difficult situation.

What grows, and survives the deer, suggests a grass and willow garden might be the answer. Many Miscanthus gracillimus - because they grow extremely well in these wet conditions and their manicured, weeping shapes contrast well with the dark woodland background, setting the open space apart, Miscanthus 'Silberfeder' for a bit more wildness and informality, probably Miscanthus Adagio and Yaku Jima for variety of size and complementary form. Small willows, not large trees ... to vary shape, texture, and color - Salix sachalinensis 'Sekka', Salix purpurea, Salix elaeagnos. But more than just miscanthus and salix, also other suitable survivors like the Rudbeckia maxima, Asclepias incarnata, Magnolia grandifolia, Magnolia virginiana. And I will continue to try other perennials whose deer survival story hasn't yet been told ... Eupatorium purpureum (and its cousins), Verbena hastata, Petasites japonicus. Other grasses, too - Panicum 'Dallas Blues', Shenandoah, Heavy Metal, Cloud Nine. Near the back, a mixed planting of Miscanthus 'Silberfeder' as background to petasites and Pycnanthemum muticum (stolen wholesale from Oehme and Van Sweden via Michael King's new book, Perennial Garden Design) - will it work where I want to try it?

Time will tell.

Plant Stewardship Index

Lokatong Creek

We went to the annual Native Plants in the Landscape conference at Millersville University last week. I attended two presentations on the Plant Stewardship Index.

The name makes you want to run for your garden spade? Don't.

Though I do not limit my plant selections exclusively to natives, I understand the value of preserving local, native plant genotypes, fighting invasive alien species, and saving natural lands from development. We have two exquisite watersheds in our little part of New Jersey - the Wickecheoke and the Lokatong. Both drain somewhere around 25 square miles, and share a rocky, picturesque plunge over their last few miles into the Delaware. These two watersheds, and the surrounding lands - particularly the sublime Rosemont Valley - need to be preserved.

Several local governments and nonprofit organizations are having success preserving farms and natural lands. But as more and more land is preserved, and development forces exert pressure to take the land for their own benefit (profit), it will become increasingly necessary to be able to show the value of preserving land, and to clearly demonstrate that preservation measures are improving the value of these lands.

Thus, the Plant Stewardship Index. This is a scientific tool that can be used to evaluate the value of natural lands, and to measure the efficacy of management measures used to improve the quality of these preserved lands. The PSI provides an index, a number, that indicates the quality of native habitat by measuring the numbers of plant species present.

It is a highly localized tool because its foundation is a list of plants that grow in a specific area, both native and non-native, each with a number assigned between zero and 10. Plants that are native, and that indicate a high quality habitat by their simple presence, have higher values. Such a list - consisting of over 4,000 plants - exists for New Jersey. It was developed by professional botanists meeting and coming to consensus on each plant's value as an indicator of high quality habitat. A similar list for Pennsylvania will soon be available.

A mathematical formula is used to calculate the PSI. It looks a little foreboding because it incorporates a statistical technique to assure more accurate results, but it's quite simple. Of course, calculating a PSI requires you to perform a survey of the land, and to be able to identify the majority of plant species living there. You don't have to actually count the numbers of individual plants in each species, just the presence of a species.

Bowman's Hill Wildflower Preserve (BHWP), just south of New Hope, Pennsylvania, has taken on the challenge of introducing the PSI to our area. This is a major undertaking for such an organization, and they deserve support. Many governmental and academic organizations have declined take on introduction of the PSI in New Jersey and Pennsylvania, so BHWP is doing a really good thing. They will soon make available on their web page all the information needed to calculate the PSI for a given piece of land. I understand this tool will be available to the general public. BHWP will also give a series of classes in use of the PSI and identification of native plant species. I intend to participate.

Here is the BHWP web address. Keep a watch for the PSI tool to appear in the very near future.

Bowman's Hill Wildflower Preserve

The Matrix

I'm planting in a matrix of native plants. Since I've cut trees to allow more light, I'm finding all sorts of changes in the "legacy" plants at Federal Twist. This week, I discovered Blue Eyed Grass for the first time since we moved here. I suppose it's emerged because of the brighter conditions. But the Blue Eyed Grass is only an incidental pleasure. The major components of the natural matrix are, at present, fleabane (Erigeron philadelphicus), a large, isolated colony of Equisetum arvense in a very wet area, numerous Carex and Scirpus species, and early season grasses I haven't yet identified. The matrix of equisetum is thriving and now forms an attractive blanket of soft texture that contrasts with the bulky form of Petasites japonicus and the sword-like spires of assorted irises that like the damp conditions.

I feel compelled to say a few words in defense of the fleabane. It's not the prettiest flower in the world, but in mass, it lights up the grasses and creates a lot of visual interest from a distance. I'm interested in using short-lived ruderals like fleabane to help prevent seeding of more pernicious weeds. I'm even hoping to displace some of the poison ivy and multiflora rose that keep so many visitors from walking in the garden. Over time, I expect the fleabane to gradually disappear as intentionally introduced plants become established and take up more garden space.

Placed amid the matrix of native grasses, carex, and sedges, plants with strong, easily "read" structure help give the emerging garden a recognizable intent and sense of order. Last year's planting was mainly experimental. Though I've researched plant selections, I really won't know what can grow here, in unimproved conditions, and what can survive deer browsing, without experimenting. One plant that came through the winter with flying colors is Rudbeckia maxima. The large, prominent, glaucous leaves are the main attraction. Planted in groups, and scattered in apparent random patterns, the rudbeckia will provide a strong visual interest throughout the year. The flowers, on tall spires, add vertical contrast, and with their long-lasting seed heads, remain attractive long into winter.



I ordered a flat of Silphium terebinthinaceum, which should thrive in my conditions. About half of them are growing. Their mature foliage, which is low but very large, should complement the rudbeckias, and their later bloom should add another feature later in the season. Do deer like to eat silphium? I'll let you know.

The verdict is still out on various Joe Pye Weeds, which I love. The emerging shoots have suffered some nibbles. Since this plant isn't a favorite of deer, I'm hoping the browsing damage is a result of the deer "taste testing," and the majority of plants will reach maturity and flower. Several Eupatorium cannabinum seem to be growing well with no damage so far.

The ornamental grasses, of course, are deer proof. More on that later.

Imagining the landscape

The future garden is a flat, rather featureless space, especially viewed from the house, which is situated on a raised mound about 15 feet above the surrounding land. Now that we're opening up the space - and the view - by taking down trees, the flatness of the land is more evident, even though there is a gentle, barely perceptible slope, moving away from the house, toward Lokatong Creek at the bottom of the hill.

I'd already been aware of the need to divide the space with screening (small trees, shrubs, large perennials) and to create spatial diversity, interest, and a sense of scale. Last weekend, we started laying out the secondary path of cedar chips through the middle of the space. (The main path will circle around from one end of the house, to the back of the garden, then back to the opposite end of the house. It will be twice as wide as the secondary path, at about seven feet.)

We got the cedar chips about half way across the field, then I cut the rest of the path with a string trimmer. Even in this unfinished state, the secondary path has reorganized my perception of the space, making clear where various plant communities, shapes, and forms might be used to make the new garden. Like a line on a blank canvas, the path suggests its own landscape, drawing the eye to previously unseen features, small surface undulations, rocks, native rushes, carexes, and equisetum.

Barely visible yet, a garden is coming into view.

Shaping the woods, opening the sky

Here on this slope falling toward Lokatong Creek, the open field was left to grow wild 40 years ago. Small, randomly seeded cedars that look like pretty green sculptures in photos from the 1960s, grew into looming, scraggly, 60-foot trees coming right up to the house.

Cutting enough to create a ring of open space has been a costly and complicated chore. The ground is wet, very wet, through winter and well into summer, so felling the trees is the easy part. Moving them is almost impossible. No heavy equipment can get through the mud. Last year a crew manually moved and chipped 30 or 40 trees. I kept several truckloads of chips to create soft paths through the future wet prairie. This year I cut more cedars myself, then realized this 61 year old person doesn't have the energy, strength or time to do the rest of the job.

So I called in Tim and am waiting for his estimate. We discussed possibilities. Sustainable approaches appear to be the easiest to accomplish and the least costly. Fire is the easiest, and certainly appropriate for a prairie planting, but the danger of fire in the middle of the woods is too great. The plan is to cut up the trees into 30-inch logs, saving the largest ones for rustic seats, and to build a chevron-shaped wall of stacked logs on the back of the garden. This gives me a screened composting and utility area as well as hidden space to dispose of the tree limbs (good cover for wildlife too). The angle of the chevron relative to the house has to be just right, though. I hope it can follow the angle of the tree tops as they recede toward the vanishing point of the new perspective we're creating.

I'd seen stacked log walls in photos of other gardens and had already thought about using some such "natural" feature to help give structure to the wildness (think of Wallace Steven's poem - "I placed a jar in Tennessee and round it was upon the hill. It made the slovenly wilderness surround that hill").

Though the ground is a mess of fallen trees, the sky has opened like an eye above the emerging field and the back line of deciduous maples, oaks and chestnuts forms a noticeable circular border that appears to surround the house (an illusion). The woods are more open too, more like the older forest at the sides of the house, allowing the eye to move into the distance through the interstices between the trees.

I want to continue thinning out the cedars (I'll leave a few) over the coming years, making a more open, park-like area around the house, but there will be plenty of brush and undergrowth to encourage wildlife.

Planting the wet prairie

Freeze and thaw, freeze and thaw. I'm thinking about what to do with all those plants arriving in April and May. With very wet clay in the back - wetland, really - I'm aiming for a wet prairie, and I'm using what I can learn from Perennials and their Garden Habitats by Hansen and Stahl (I finally found a used copy discarded by the Iowa City Public Library), and the little Noel Kingsbury has written on the subject. My plant list (partial):

Panicum virgatum 'Rotstrahlbusch' - 30
Spartina pectinata 'Aureomarginata' - 6
Molinia caerulea 'Strahlenquelle' - 25
Molinia litoralis 'Transparent' - 6
Eupatorium purpureum 'Coelestinum' - 10
Calamagrostis brachytricha - 15
Sesleria autumnalis - 12
Carex muskingumensis - 12
Darmera peltata - 15
Euphorbia palustris - 4
Matteucia pennsylvanica - 12
Kniphofia caulescens - 9

Eupatorium fistulosum, other panicums, a start of a hedgerow of Magnolia grandiflora, viburnums, ilex verticillata and other plants are already in the ground. I can't wait to see what thrives, what just survives, and what is dead.

This is an experimental garden and I'm looking for every source of information I can lay my hands on. If I could read German, I'd be talking to the folks at Hermannshof (see the link below for an automatic translation into English).

Hermannshof Garden

Are we gardening yet?

After an extraordinarily mild winter, we had a whopping snow storm last weekend. New York City, about 65 miles to the east, had the most snow ever recorded in a 24 hour period. Here's how it looked at Federal Twist.
Warm weather - again - the following week quickly melted most of the snow. The Lockatong Creek is running overfull, as are the little unnamed tributaries around us. I continue reading gardening books - now Dan Pearson's The Garden: A Year at Hope Farm - and ordering plants. As usual, I've reached the surfeit point and am feeling I'll never have time to build the stone walls I want to build, expand the front planting area, cut down the worst of the ragged cedars blocking the view of the sky, build the pond, and plant 30 Panicum virgatum 'Rotstrahlbusch', 25 Molinia caerulea 'Strahlenquelle', 15 Darmera peltata, and all the many, many other plants that will arrive, probably bare root, when I have only one rainy day left for gardening before leaving to get back to the City for work on Monday. Why do I do this?

As spring arrives, I'll remember, as in the past, all this will not get done in one year. And the better for it.

Christopher Lloyd

My March copy of Gardens Illustrated arrived today. The cover features Christopher Lloyd as a new columnist, and inside is a continuation of an interview with him. Ironic timing and unfortunate since he died a few days ago. I remember when Phil and I visited Great Dixter in 1985. We passed him standing in the rose garden, talking to a young man. I was too shy to acknowledge him, much less try to start a conversation, but I'd been a reader of his books for a few years, and liked his prickly, opinionated style. He wrote about many plants I had no knowledge of, and that challenged me.

He changed the Great Dixter garden in many ways since I visited. Pulled up the rose garden and planted a tropical garden, I understand. And continued to make waves in the world of horticulture. In his first, and last, column in Gardens Illustrated, he writes of his interest in learning about the native flora in the places he visited - for example, learning that opuntias grow on the southern shores of Lake Michigan. "Nothing extraordinary about that you'll say, and possibly also add that many opuntias are extremely hardy," he writes. "But I wasn't born with that knowledge. The whole of life is a process of learning, which will only end with my death."

Great Dixter will continue through the efforts of The Great Dixter Charitable Trust.

Friends of Great Dixter
Great Dixter House and Gardens

Complaint Department

Our mass market-oriented nurseries offer gardeners in the U.S. a far more limited choice of plants than our friends in the U.K. I'm looking for sanguisorba tenuifolia Alba - have been, on and off, for several years. Just try a Google search and see how many hits you get in Europe and the U.K. Either I can't find it offered on this continent, or no stock is available.

Garden Plans

I sometimes think garden plans should only be quick sketches - pencil lines and a few abbreviations on a scrap of paper. Once the actual garden-making starts, the plan is subject to change, for change it will. Landscape architecture, with its emphasis on built structures, rather than plantings or plant knowledge, seems to have a big financial impetus to promote elaborate, colorful, detailed plans - and a beautiful garden does not always result. But the plan itself may be pretty, or intriguing. The design drawing takes on a life of its own, and may hinder exploration of new ideas that arise in the process of making the garden. This is especially true when the client is paying many thousands of dollars for a design/build project. I once heard Rick Darke say he never drew a garden plan. He always works directly with the landscape and plants.

Heronswood Nursery's New Catalogue

The new Heronswood catalogue came in today's mail. Glossy paper. Lots of color photos. Accurate, informative, descriptive text. All good in the usual nursery catalogue. But the sense of relationship with a unique person is gone, replaced by the anonymous voice of commerce. I'll miss Dan Hinkley's (or his helpers') wry, humorous stories of plant exploration in far-off parts of the world. The old catalogue left a lot to the reader's imagination. Browsing through it was a joy and a mystery. I'll miss that experience. It was a part of gardening for me.

Planting Design: Gardens in Time and Space by Piet Oudolf and Noel Kingsbury

About time for someone to take perennials so seriously they write a manifesto.

I've read all the books by Oudolf, Kingsbury (and occasionally others in changing combination with one or the other). I have to fess up to ordering this book several months before it was published by Timber Press (bless Timber Press for their wonderful selections). I'm a fan of these guys.

At first I found this book off-putting, distubing. It seemed to be trying too hard to make a point - or several points. Now that I've read it three times, I realize it simply contains so much information it's almost bursting out of its covers. Gardening is getting political. If you remember an article by Michael Pollan in the New York Times magazine several years ago, in which he ripped such authors as Ken Druse for promoting "natural gardening," a term which he and others have claimed as virtually meaningless, you know how political it can get.

If Planting the Natural Garden was poetry, this book is, indeed, a manifesto, but it is much more. Its focus is herbaceous perennials, and the art of designing with plants to make gardens, as opposed to landscape architecture, which is usually practiced with minimal use of plants and minimal knowledge of how they grow.

Look Back: Simplifying Plantings

Looking back from this first day of the new year, I'm thinking about changes I would have made to the Rosemont garden if I'd been there another year.

Simplification of the planting would have been at the top of the list. The initial planting was partly an experiment to see what plants would thrive in the rather difficult conditions my little plot of land offered, and what plants could survive deer browsing. Because of our large deer population - they are literally destroying the forests in our area by preventing new growth - selection of plants unpalatable to deer had to be among my top priorities. Ornamental grasses, highly fragrant plants, plants usually found to be deer resistant (see link) made up most of the garden. I did take some risks. Lavatera thuringiaca 'Barnsley', for example, grew into a six-foot shrub, with profuse bloom, in the first year-and-a-half, and though in an exposed position, suffered no deer damage.

Now that I've observed the garden as an outsider, I see more clearly the need to create greater simplicity with larger groupings of similar plants, balanced by sufficient variety to provide interest throughout the seasons. I did plant rather large groupings of Echinacea purpurea 'Magnus' (not the first preference, but the only one available), Filipendula rubra 'Venusta', Eupatorium fistulosum and 'Purple Bush', Persicaria amplexicaulis 'Firetail', and Nepeta sibirica 'Souvenir D'Andre Chaudron', which were all quite effective in their season, but fewer species of grasses would have created greater impact and less fussiness at the height of summer.