Green Walls

What’s with the fad for plant walls? I’ve been struggling with one for months now. You can get to about ninety percent success, but the ten percent that’s dying spoils everything. After talking to experts and looking at plant walls all over town, I’ve concluded that ninety percent success is about as good as you can hope for. The bottom line is that they don’t bear close scrutiny. If you want a plant wall, just make sure it’s on the other side of the room.

The plants grow on mats of soilless medium clipped to a frame. They are watered by a drip irrigation system with emitters on eight inch centers. The installation is expensive and the ongoing maintenance really adds up. You could buy art and have fantastic cut flowers, delivered twice a week, for less.

And, honestly, I don’t get the appeal. I’m just guessing, but I think people are turned on by the displacement. A bed of pachysandra goes unnoticed on the ground, but once you start carpeting walls and ceilings with it, as they did at this Ann Demeulemeester boutique in Seoul, you are suddenly on trend. “Luxury meets Green$$$,” the headline reads. Maybe not so much as it starts dying out in patches.

I really start to lose it when buildings like this are described as “green.” Yes, there are lots of plants, but they are sustained by life support systems that needlessly consume resources. The goals of green building are simple: to diminish the human footprint on the planet by using fewer and more sustainable resources. These goals are not met by creating illusions; they are met by making a lot of modest, responsible, daily choices that add up to a kind of ethics. Inflate your tires, carpool, use more efficient light bulbs and turn them off when you leave the room. And design buildings that make those kind of choices attractive.

This is not to say that greening needs to be boring or frumpy or uninnovative. What it does need to be is effective. If the numbers don't add up, it ain't green. You can't get there by posing and making reference to attractive trends.

The fantastical "green" shown here is just BS:

http://www.huffingtonpost.com/2008/11/23/fantastic-and-visionary-d_n_145848.html

And the sooner we can decouple escapist fantasies from green thinking, the sooner we can make progress with it.

Killing Frost

Tell me why I’m elated.
I pour my heart into the garden, but there’s a thrill when it’s laid waste. A chance to see things change overnight, then to start over…. I don’t know.
And it interesting to see the plants that are very tender (impatiens, coleus, cuphea, ipomoea) winnowed from the plants that can take a couple degrees of frost (abuliton, callibrachoa, lantana).

Salvia leucantha

This is my favorite tender sage. Nice, fuzzy grey leaves, shaped like willow leaves, on plants that gradually gain stature as the summer goes on. Not a gorgeous plant, but presentable, which is more than you can say for most of its cousins. By October it's grown to a substantial little shrub and every twig extends an arching raceme of fuzzy purple bracts. On some plants the petals that project from the bracts are violet, on others white. The arc of the flower stems reminds me of bleeding heart, another plant I love.

This sage is hardy in California, but the plants are unwieldy after a couple years. They are best in their first fall, so it's to our advantage that we have to replant every spring.

Full sun and lean living are best. It can get sloppy with too much shade and nourishment.

tender succulents

I'm making a mental note for next spring: plant sunny window boxes with tender succulents. This collection of Crassula, Echevaria, Aeoium and Sedum will stand a couple degrees of frost, but won't make it through the winter. On the other hand, it will thrive without daily watering in the summer.

To Autumn

to set budding more,

And still more, later flowers for the bees,

Until they think warm days will never cease,

For Summer has o’er-brimm’d their clammy cells.

High Point 3

Here's another dreamboat from my trip. Once a fire station and now a beauty shop.

High Point 2

I may never want to live in a house that looks like Mount Vernon, but I love the way this front lawn runs right up to the portico without any transition in the way of terracing or foundation planting.
This is incredibly hard to pull off. It works because the architecture is so good, and the relationship of the building to the ground plane is completely resolved.
Capability Brown loved this effect. I’ve also noticed it in paintings by Stubbs. Both artists are about contemporary with the original Mount Vernon, so the minimalism that looks current today is also a period look from the middle decades of the 18th century.

High Point

I was recently in High Point, North Carolina and saw a house with an interesting front yard. The house was set back from the street, and a little valley ran across the yard. It was wooded, but the trees were thinned and limbed up enough to grow lawn beneath. A pattern of serpentine grass paths ran between beds of dark ivy, and patches of sun showed through the green.

Miller

If you start at the Battery and walk along the Hudson, you pass through a series of terrific gardens. After the Oudolf garden at the tip of the Battery is Wagner Park, designed by Laurie Olin. A tiered lawn lies between a pavilion and the river. It’s an urban beach: unpretentious and scaled to the grandeur of the harbor view.

At either side of the pavilion are two formal flower gardens that were planted by Lynden Miller. These gardens are a good example of the current official style of public flower gardens in New York. This idiom is represented by Miller’s own work at the Conservancy Gardens in Central Park, Columbia, and the New York Botanic Garden, and it the work of others, as in Bryant Park.

http://www.publicgardendesign.com/projects/index.htm

These gardens are formal; geometric beds and sheared shrubs form compartments containing bright vignettes. Flowering shrubs and large perennials are massed at the back of the beds and a huge variety of tender annuals, bulbs, dwarf evergreens, and foliage plants are brought together to deliver maximum color through the warm months. Every corner is treated as if it were an arrangement of cut flowers, and the display is kept going for months on end.

Miller’s palette is as varied as Odoulf’s, but entirely different. Her plants are mostly tender exotics with colored leaves and vivid flowers, and her compositions rely on bold contrast. There are great things here (like Cuphea ‘David Verity’, pictured) that really thrive in New York’s summer. It’s a sophisticated gloss on the bright, old fashioned bedding flowers - petunias, marigolds, begonias.

I criticized the Oudolf garden for patchy over-assortment. His taste runs to “natural” looking meadow and prairie plants, informally composed. This creates an expectation of unified effect. Separating the plants into patches contradicts the main idea.

Miller’s plantings are even more assorted, but it doesn’t really come off as a fault. Her plants are “artificial” and the layout is formal, so different expectations prevail. The eye moves from one vivid arrangement to the next, seeking novelty, variety and diversion. It’s like walking down a city street and beholding one character after another.

All this is very much in the spirit of the tidied New York of recent years. Nice and safe, intensely maintained, ladylike.

Oudolf

A few weeks ago, with a storm approaching, I went down to the Battery to see Piet Oudolf’s Garden of Remembrance. This kind of perennial planting, which emphasizes texture and motion rather than flower color, is spectacular in September.

The variety of plants is wonderful. This is a gardens where I’d appreciate the information gained from labeling plants more than I’d resent the eyesore of all the tags. Fortunately, the Battery Conservancy website publishes a list:

http://www.thebattery.org/gardens/gorplantlist.php

Among the standouts: Calamintha nepeta nepeta, Anemone ‘Honorine Jobert’, Agastache rupestris and A. ‘Blue Fortune’, Panicum ‘Shenandoah’, Amsonia hubrechtii, and Persicaria ‘Firetail’.

This garden hugs the shore of the battery between Castle Clinton and the water. Irregular beds are separated by gravel paths that wind through a grove of plane trees. At water’s edge, exposed to the sun and wind, is a paved promenade. Here concentric rows of raised beds and paths make a more formal edge to the garden.

The odd thing about this garden is that the planting is innovative, but the layout is old-fashioned. (I could believe that the plan is a nineteenth century relic of the ‘gardenesque’ school. The paths meander without destination and ‘specimen’ plants seem chosen to show off the breadth of the collection.)

The plane trees and gravel paths hang together as a coherent expression, but the herbaceous layer is over-assorted. Oudolf’s planting palette suggests meadows and prairies, wild places where plants mingle and mix in a continuous carpet. In this garden the varieties are separated and planted in mid-sized drifts and clumps. To me the patchwork effect is disconcertingly suburban.

That said, this still a good place to see the current thinking about perennials. But I’d like to see an edited selection of these plants, composed with greater deliberation.

Oudolf has the commission for planting much of the Highline.

Sophora

may be my favorite big tree for planting in the city.

Tropical

Gardeners in temperate climates have been bedding out tropical plants for a long time: coleus, caladiums, impatiens, begonias, etc. Few hardy plants offered their extended season of bloom and striking foliage. When cold weather comes, adios.
Some people are uneasy with this. I hear people express a categorical preference for hardy perennials, implying they are somehow classier. Even among permissive gardeners, there is a sense that some tropicals are suitable bedding plants and some should stay inside. But that prejudice seems to be lifting, and more and more I notice monstera, crotons, asparagus ferns, colocasias and wandering jew planted with the familiar tender annuals in our summer gardens.
In New York, with our torrid summers and reliance on container gardening, these alien plants really contribute. They are a horticultural match of the city’s human diversity.
Still there’s a time and place for everything, and I don’t think I’d work a Monstera into rose garden. For the most part they belong in containers near the house. If you have the space and winter sun, you can haul them in when the time comes.

Angelica gigas

The big black Korean Angelica is a sinister curiosity. Usually you see a lone specimen towering among extreme annuals, the way castor beans were once grown.
Yesterday at the Brooklyn Botanic Garden I saw a whole colony of it. Under the shade of a big Pin Oak, its dark umbels were silhouetted against a sunlit hill of grass. Stunning and unexpected, it was the uniting element in a garden composition. Hats off to the gardeners who planted this.
I was surprise was how well these were doing under the oak, which casts almost full shade and must have competed with the angelica for water.
This plant is a biennial that I gather is a little tricky, as cultural instructions vary from source to source. I believe those at BBG have self-sown, as outlying plants were strewn around from the main clump.

Wire Vine

The Wire Vine, unexpectedly, is hardy. I thought it was tropical and expected to tear out a dead crown last spring, but it was breaking growth, so I cut it back hard. Now it’s going full steam.

Wire Vine is of the genus Muehlenbeckia. I think the one I have is M. complexa. Its leaves are a rich green, and its stems are indeed wiry. Some of the little oval leaves are held out above the plant in an effervescent halo. People find this plant adorable because all its parts are so tiny and neat. They fall into the voice they use with puppies.

I’ve seen wire vine trained on topiary frames, but it doesn’t twine or cling closely. It sprawls in a miniature way and needs to be tied in. I intend to experiment with this plant. I can imagine it among paving stones, in raised containers on a terrace, or trained as bonsai. One day it might be among the workhorses of terrace gardens.

Sun, moderate water and fertilizer: no special needs. I usually see it being sold as a houseplant.

Ipomoea

The rampant chartreuse vine spilling from planters all over New York is Ipomoea ‘Marguerite,’ aka the Sweet Potato Vine.

A lot of people started planting Marguerite about 10 years ago, but I can’t quite get used to her as a rank and file member of our flora. She’s a dominatrix, and her vigor has a supernatural, mutant-Kudzu quality. Still I use her in new plantings all the time because she makes a fast start and gives everyone the impression that they know what they are doing. Marguerite is a tender tropical, and fortunately she’s laid flat by the first frost.

There are a few other Ipomoeas, including black leaved ones that can be used to macabre effect. “Blackie” has a divided leaf and nice violet flowers that resemble morning glory, which is in the same genus. I’ve never noticed flowers on other Ipomoeas.

‘Carolina Bronze’ has an interesting bronze brown leaf that mixes poorly with most other plants. I’ve liked seeing it grown with Coleus ‘Trailing Red’ and the scarlet dahlia with dark leaves called ‘Bishop of Llandaff.’ It also looks good at the base of big blue-leafed agaves. Generally Carolina lends herself to sophisticated, highly edited planting schemes of foliage in muted pastels.

‘Tricolor’ is just awful. Its leaf is green mottled with white, lavender and pink.

I think we are just getting started with Ipomoea. New varieties are introduced every year, including one marketed as a more “restrained” version of Marguerite.

Feral petunias

Little magenta petunias, growing from cracks in the pavement, appear all over New York in August. They are the feral offspring of hybrid petunias. The descendents aren’t as showy as their ancestors, but they have recovered the resinous honeysweet fragrance that is faint in some of the garden hybrids.

I think these wildlings can carry on like this, reseeding for years. They aren’t really a substitute for garden petunias, but in their way, they are splendid.

Four-o-clocks, nicotiana, cleomes and verbena: All are tropical annuals that seem to perpetuate themselves by seed.

Tuberose

I grow tuberose for its scent on hot summer nights. The flower is white and held up on a strong stem so you don't have to stoop to sniff.

It grows from bulbs that are set out after the soil is warm. Bloom starts in July and continues through September. Unlike spring bulbs, tuberoses do not all bloom together. One bulb will bloom 60 days after planting, another 90, so there’s a long staggered season. Tuberose is tropical, flourishing in sun and heat and rich, moist soil. Put out too early in cold soil, they sulk.

Their long grassy foliage is unkempt, so I have planted them among daylilies and grasses where the leaves will be concealed. Every year I think that a 15” pot planted with a dozen bulbs would be a good idea. I have a notion that in isolation, the plant’s messiness would be less a fault, but I have yet to grow them that way.

I’ve grown both the double “Pearl” and single “Mexican White.” Both are fantastically scented, and I surprised myself when I found I preferred “Pearl” as I usually favor singles.

The bulbs can be stored inside over winter. Leave them in the ground till Thanksgiving -- they don’t usually show signs of dormancy. I lift the bulbs leaving the top growth attached, then wash the soil from the bulb and roots and just leave the dug plant outside to air dry. Their leaves reluctantly yellow and drop. When frost is expected I bring the bulbs with all their top growth attached inside and keep them in a cardboard box in an unheated room. They spend the winter like that.

Around tax day I take a look. All the foliage and dried roots can be pulled from the bulbs. Usually they have offset dozens of little bulblets that I break from the mother bulb. (These will throw up a mess of little unblooming shoots if they are left on. The bigger offsets will send up flowers.) Usually I pot up some of the bulbs and start them on a heat mat. Just as they were reluctant to go dormant, they are reluctant to resume growth. It’s usually a month or so before they break dormancy. Wait till the ground is really warm before they are planted out.

Ivy

I love ivy grown up trees. English ivy is dark, evergreen and macabre. It lends an elegiac, Hubert Robert sort of melancholy to the scene. When I die, I want a grave marked with a slate headstone in a country cemetery with black locust trees clothed in ivy. Wrought iron fences, bearded iris, yuccas on a lawn that goes brown in the summer. I imagine an atmosphere of dereliction that invites reverie and mischief.

Boston ivy is another story. It is bright and glossy and shimmers in the breeze. In high summer it drapes from branches in great luxuriant swags. It turns a vibrant crimson in autumn.

Ivy does not hurt the trees. Some people get upset when they see ivy in trees, but they should realize that they grown together in nature and that a bit of ivy does no harm.

The Pegged Rose Blooms

Photographed June 15, and a success.

I hoped the rose would send up flowering shoots all along the length of the pegged branches. The more vigorous shoots are towards the base of the plant. The shoots further along the stem are weaker. We’ll see if they gain momentum. It would be nice if they bloomed later and extended first flowering cycle for a couple weeks.

On the other hand, we could have pushed this rose too far.

Chinese

I visited the Chinese Scholar’s Garden at the Staten Island Botanical Garden, and what a treat it was. The garden opened in 1999, and the planting is now mature.

This garden was designed and “built” (as they say of Chinese gardens) by the Landscape Architecture Corporation of China, an entity with ties to the Chinese government:

http://lac.com.cn/

Materials, workmen and expertise were all imported from China, and the results are as authentic as you could reasonably hope for. The same outfit built Astor Court at the Metropolitan Museum.

The garden was intended to be a “standing cultural ambassador” of China. I wish more countries would adopt this policy, especially France, Iran, Spain, Italy, Brazil and the Netherlands. China aced this one.

I love Chinese gardens and wish they were more influential. Westerners have been preoccupied with upturned eaves and scholars’ rocks and overlook the brilliant planning and sophisticated handling of light, space and sound. These aspects of Chinese gardens transcend chinoiserie:

1) The gardens are private, walled sanctuaries. Their relation with the world outside is minimal. Within the walls is perfected world where people live in harmony with nature. Everything within is imagined.
2)The gardens aspire to the state of landscape painting. Impressions of scenery – usually mountains and rivers – are created. (But the scenery need not be a Chinese landscape of misty mountains; it could be any vision of paradise: a salt marsh, a woodland, or a dream of Claude.)
3) Architecture is integral to the concept. As at the Alhambra or Vaux, pavilions, paving, steps, walls and pools make the bones of the garden, and these structures make a place for humans in the envisioned paradise.
4) Space and light are handled to suggest infinity. For example, a pavilion built at the edge of the garden would not be built against the outside wall. A narrow courtyard, just a slot, is left between the outer wall and the pavilion. This admits light to the back of the pavilion, and by thoughtfully planting the courtyard and placing windows in the pavilion and outer wall a layered stage scenery is created – the illusion of depth conveyed in 3 feet of space.
5) Great attention is paid to all the senses. Sounds and echoes, the feel of cobbled paths underfoot, the alternation of dim and bright spaces, dark waters and bright, scents.
6) Opportunities for seclusion, evasion, retreat and secret assignations abound.

I long to build myself a garden based on these principles in a tough, low rise, built up area, like Bushwick. I would abstain from details in the Chinese manner, and build it in plain construction of the local type. The pavilions would be adapted for the needs of my life: a public room for entertaining, a library, a kitchen and dining room, a bedroom, a bath. The remainder of the garden would be mostly water, with a limited number of my favorite plants, and all my attention directed at managing light, shade and reflection. From the street it would look like the adjacent buildings and go unnoticed.

All Praise

I love this front yard.

It’s a homey essay in formality. There’s not even a nod to the Landscape tradition -- with its asymmetries and allusions to acreage and scenery -- which is now the conventional way to design suburban front yards.

Geometry, in this garden, is put to use to mark out the incremental transition from the public street to the private house: from street, to sidewalk, over the little wall, across the lawn, up the steps, and onto the porch. The layers of increasing privacy are set out as a row of parallel horizontals. Then the walk penetrates straight through them to the front door.

All the details are just right. The little cobblestone wall is inspired. The lawn lays in a quiet expanse. The paired clumps of sedum, hosta and Alberta spruce are enough to mark the path. Russell Page wrote about a garden in Norfolk where a geometrical axis was “sketched” onto the featureless terrain with four pairs of simple wooden gates. “The most desirable quality of garden design…” he said about this sketched quality. And here too the modest geometry is becoming. Formality need not aspire to the grand manner.

And the porch is good. It’s deep enough and set high and tucked back into the body of the house. You could sit on it quietly and go unobserved from the sidewalk. That’s what makes a good porch.

Nothing fancy plantwise. No showing off. No allusions to imagined topography or lifestyle. No pretense of any kind, but this garden has everything it needs for a modest house to sit on the street with composure and dignity.

Technique

Someone on Metropolitan Avenue wired pony packs of impatiens to the railing of his stoop -- red ones on one side and white ones on the other. A week later he nested them in little cozies of aluminum foil. So far the impatiens are doing fine.

For almost 10 years I gardened in a community garden in the East Village. We gardened in 4 foot by 8 foot plots. In community gardens you see what happens when people have a lot of energy relative to the size of their projects. All kinds of radicalism and fussiness and magical thinking are directed at overstuffed plots. Roses, tomatoes, honey locusts, herbs and lavender grow cheek by jowl with houseplants set out for summer, rescued specimens brought in from the curb and pass-a-long plants from the ancestors.

We had a gardener who brought a thermos of boiling water to pour over a row of parsley seeds. There were people who pruned down to trunks and people who could hardly bring themselves the snip a yellowed leaf. There was a lady who enclosed her plot of vegetables in a palisade of sharpened sticks and a man who enclosed his in net covered frame that looked like a kennel. They were all, in their way, successful.

People want to learn gardening secrets. They want to dose their plants with elixirs and believe that some people have green thumbs. In fact most gardening wisdom is conventional and unsurprising. It’s in every book and all over the internet and when you think about it, it makes perfect sense. The “secret” usually is finding the wherewithal to do things properly at the right time of year.

Most garden plants, once their basic needs are met, are awfully accommodating. A lot of what gardeners do they do for themselves.

Wisteria

I can pretty easily forgo planting most of the species that appear on the invasive plant lists for our area. There are sore temptations, like the Tea Viburnum. And several garden stalwarts, like English Ivy, are frankly irreplaceable.

But forgoing Wisteria is a brutal challenge. No vine matches its combination of exuberance and refinement.

I went around with the illusion that only the Japanese Wisteria, Wisteria floribunda, was invasive. (I failed to read the fine print on the Invasive Plant Council of New York State’s list.) The Chinese Wisteria, I believed, was safe and almost as good: a little less elegant and a little less fragrant, but with bronzy new leaves that set off the flowers. I took this picture of Wisteria sinensis on Fire Island to show that we can keep our bearings with invasive plants without compromising our appetite for Wisteria.

Then I double checked and found that the Chinese Wisteria is equally invasive. This a real blow because the recommended substitute, the American Wisteria frutescens, doesn’t make the same gorgeous show. It’s a nice enough vine, but I’d have a hard time planting it without feeling compromised.

Over the years I’ve shilly-shallied a bit on the question of invasive plants. I’m outraged that my beloved Black Locust is on the list when its nativity is in question. I’ve wondered about the actual harm of growing invasive plants in gardens if they are already loose in the woods. And I’ve thought the whole issue is a little misplaced because there are no unspoiled native ecosystems left to defile.

But gradually I’ve become a fundamentalist on the question. Because of choices gardeners have made euonymus and barberry have crowded the native shrubs from our woods. It was an innocent mistake, but now we know better. There are vastly complicated environmental problems that we can only begin to solve, but the problem of invasive plants belongs to gardeners and we should own it.

BTW I use the invasive plant list provided by the Brooklyn Botanic Garden:

http://www.bbg.org/gar2/pestalerts/invasives/worst_nym.html

Higan

Having dissed the flowering cherries I have to put in a word for the Higan cherry, Prunus subhirtella pendula. It is really something, like a ruined cathedral hung with candyfloss.

Like most pendulous trees, it looks at home near water. I could also imagine it hanging above a steep ravine.

Taste

This spring I studied the flowering cherries. I thought I should get some clear ideas about them because, in my head, the varieties mostly run together.

Then the crabapples bloomed. What a relief to be able to let go of the cherries and just enjoy the crabs. Their fragrance is as fine as the lindens, and it’s as free. In many crabs the buds are deep pink, but when the flowers open, they are white. I keep an eye on the crabapples for the day when the two-tone effect peaks.

The cherries bore me, but the crabs are a delight. I don’t know why. The extravagance of both is comparable. And objectively, most of the cherries are better garden trees: they have a tidy habit compared to the crab’s awkwardness, more disease resistant foliage, better bark and fall color. But the blooming crabs, especially the straight species Malus floribunda, are a high point of spring for me.

I think knowledge and involvement with plants only serves to sharpen these kinds of preferences. And it’s a good thing. Preferences should be exercised. Gardens holds together when there is an abiding taste behind the thousand choices that guide their creation. They go wrong when they try to have a little of everything.

Better than Forsythia Part 2

I feel a little chastened about my screed against Forsythia. Last weekend I was in Connecticut, among people who love it. It looked great along the highways -- I’ll say that for it.

Still I stand by my disapproval of planting Forsythia in Brooklyn.

But say you are planting a typical Brooklyn garden, and you love Forsythia because it’s bright and early. Corylopsis (recommended after the last Forsythia tirade) is too wan and toned-down for your taste. What you want is uninhibited brassiness to go with the tulips and flowering cherries.

So plant Kerria. It’s resoundingly yellow, and, unlike Forsythia, the flowering repeats a little after the initial flush. Dirr says it’s “ideally sited in partial shade.” The leaves are neat, and the stems are distinctly green and ornamental in winter. The photo shows the double flowered variety, which is more common than the more elegant single.

Without a Greenhouse

Every year I overwinter a bunch of cuttings that I take from tender bedding plants. When spring finally rolls around I wonder if it’s worth the trouble.

This sorry lot goes out for a couple of weeks of acclimation before they are planted. Their winter leaves drop so they look worse now that they have all winter, but new growth has broken and they will be fine. I plant them out when the soil is warm.

A few rules to live by during the six months they are inside:

1) Keep them alive but don’t promote growth. Minimal water. No fertilizer. They do as well in little pony packs as 4” pots.
2) Keep the terminal buds on the plants because they produce hormones that promote rooting. The cuttings will get lanky. Plant them out that way and pinch them back once they really get going.
3) Give them as much sun as you can. South windows, etc.
4) Don’t pot them up to get a jump on spring. This sets them back and even kills them.

Ephemerals

I Iwas lucky to see this patch of Bloodroot. The flowers are so fragile they last only a few days -- even less in the warm weather we’ve had. So I saw this bunch at its absolute zenith.

These fiddleheads (I think they belong to the Cinnamon Fern) are covered in astonishing soft fuzzy jackets. I’ve never seen anything like it. The next day, the fuzz had broken apart and fell like rags off the unfurling fiddlehead.

Washtub Azalea

Nobody fusses over this azalea, but it's been comfortable and thriving for many years. It grows in about 8 inches of soil in a galvanized washtub. Over the years a layer of decaying leaves has accumulated – I venture that is all the feeding the azalea gets. The washtub sits in front of a south facing house, shaded by a Zelkova tree.

The plant is perfectly suited to its situation so it really can thrive on neglect.

This is one of my favorite azaleas, a Kurume hybrid called ‘Coral Bells’. Its small, beautifully formed blossoms are a good, strong, warm pink. The color is about as intense as I like to see in April.

A Pegged Rose

Some friends in Connecticut are lucky to have a nice bush of the rose ‘Heritage’.

Few roses have flawlessly graceful, fragrant blossoms on a bush without functional defects, but ‘Heritage’ is such a rose. Its sole shortcoming is a rangy habit. It tends to throw rampant shoots that aren’t quite stiff enough to support themselves - though it’s not quite a climber either. What ‘Heritage’ needs is a low fence to sprawl over.

In my friends’ Connecticut garden ‘Heritage’ grows beside a boulder, and so we tried the old technique of pegging the long shoots over the rock. In March we cut out everything but last year's long shoots and fanned them over the boulder. Their ends were tied with twine to pegs driven into the ground.

Pegging is a nineteenth century method that was used with the Hybrid Perpetuals. The theory is that roses tend to send short spurs bearing flowers from the portions of the main branches that grow horizontally. I’ve found this to be true with climbing roses.

Back with results in June.

Ipheion

Peonies are drop dead gorgeous for a few weeks around Memorial Day. Then, if they don’t get mildew, they are decent citizens that go unnoticed for the rest of the year.

Their emerging foliage is interesting too. It unfurls with gusto. I love how it is set off here in a field of starry Ipheion.

This little bulb is perfectly hardy, leafing out in winter and blooming as the peonies break growth. Eventually the peony foliage will conceal the passing Iphieon. Like peonies, Ipheion resents disturbance. With time a few bulbs can make quite a show. So the two plants settle into a long, unexpected companionship.

Adding something for fall (anemone ‘Honorine Jobert’, say, or chrysanthemum ‘Mary Stoker’) would round out the calendar. The freshness of the fall flowers, in contrast to the patinated peony foliage, will appeal as much as their color.

Ruderal

On April 10 Peter Del Tredici, from the Arnold Arboretum, spoke at MetroHort on Wild Urban Plants. I think he’s on to something.

The gist of his lecture is that urban environments create horticultural conditions (disturbed, compacted soils, expanses of pavement, urban heat island warming, etc.) that support a distinct community of plants. Cosmopolitan in origin, these plants are largely reviled as weeds: ailanthus, black locust, mugwort, bindweed, chicory. We struggle to eradicate them; even legislate against them. Instead we might recognize their possibilities for the ruderal landscape.

(Learning the word “ruderal” was worth the trip up there: “growing in rubbish, poor land, or waste places. From Latin rudera, ruins, rubbish, plural of rudus, broken stone.”)

Del Tredici is working on a book, Wild Urban Plants. It goes to the publisher in October. It sounds like Weeds of the Northeast, horticulturally considered. I look forward to seeing it.

There is a lot wishful thinking about native plants: You can earn a LEED credit by planting a community of natives on imported soil and handing it over to the maintenance man to nurse. I don’t want to discourage well-meaning gestures, but it’s hard to see how this kind of planting accomplishes much in the way of plant conservation. (What is actually needed is a whole preserved ecosystem where the plants can endure in a community of organisms they evolved with – something beyond the purview of green building.)

For urban planting we might look instead to these ruderal “natives” that are so well suited to the actual growing conditions. Del Tredici has planted meadows of yarrow, chicory, goldenrod, and bouncing bet. And the black locust is as fine a tree as grows.

I’d be interested to know if the planting schemes for the High Line consider this line of thinking. Ruderal natives are growing there already.

Little Trees

Shrubs in nursery containers are cute, and people plant a lot of them. Eventually everything gets claustrophobic. Nothing can compete. It’s dismal.

You want to hack them down to size or overhaul the whole place and start fresh. But consider retaining some of the shrubs and limbing them up, creating a grove of little trees. Light is admitted and an understory of shade plants can carpet the ground below. In a confined area a miniature forest is not ridiculous. It gives a settled look. It couldn’t be nicer.

Shrubs that form nice trunks lend themselves to this treatment. Pieris is excellent because of its distinctive undulating habit. Rhododendrons, hollies, euonymus, yews, rose of sharon, mountain laurel and aucuba are all suitable. Suckering shrubs that throw up new shoots from the base – like roses, spirea, and hydrangea – are usually not.