Staying Flexible

Hardscape and permanent plantings allow for an ever-changing palette of colorful bulbs and perennials

NOW THAT WE’VE COVERED THE BASICS OF PLANNING, DESIGN, AND PLANTING, it’s time to see how the principles we’ve discussed get put into action. In this article and the two that follow, we will focus on issues that have arisen in actual borders that we have created for clients in the Seattle area.

The most important feature of the borders discussed below is the preponderance of hardscape and structural framework plants. These unchanging (or slowly changing) elements allow for a high degree of flexibility in the choice of what we call “infill” plants. In fact, we fully expect the plantings as a whole to change, perhaps radically, over time. This sort of layout is ideal for the gardener who likes to experiment with plants, and whose garden therefore experiences a high rate of “turnover”; it’s also well suited to gardeners who, for whatever reasons, anticipate moving from higher- to lower-maintenance plantings.

THE SETTING

The property we were called in to work on is on an island in Puget Sound. To a much greater extent than other sites we have encountered, it was a proverbial blank slate. There was little more than a farmhouse surrounded by seven acres of meadow grass, and relatively few trees and shrubs to soften the landscape. While we agreed that an overall plan was needed, our clients” immediate concern was for the entry area. Under the previous owners, the driveway had lain directly in front of the house. Our clients removed the driveway not long after they moved in, with the result that the area in front of the house was a sea of mud, with plywood sheeting as a walkway. Our clients wanted to transform this area into a formal parterre. In the absence of defining features on the property, this seemed as reasonable a step as any other.

4 Border Basics: Staying Flexible

OVERVIEW When the layout is reduced to its basic elements, its advantages become clear: not only is there an attractive, year-round framework, but any color scheme or style of planting could easily be substituted for the present one.

THE HARDSCAPE

We decided to create slightly raised planting beds so that the paths wouldn’t become muddy after a violent rainstorm or after being hosed down. Our clients chose cobblestones for the curbing and bluestone for the walkways. These materials harmonized nicely with each other and presented a neutral backdrop against which to work.

We were asked to make the main walkway wide enough to accommodate two people walking side by side. With that mandate, and keeping the scale and dimensions of the house in mind, we decided to make the main path eight feet wide, the side paths four feet wide, and the tertiary paths two feet wide. The footprint of the area wound up being basically equal to that of the house, with extensions toward the drive and around the porch of the house. Initially, the eight-foot-wide path seemed excessively wide, but as the lavender hedging grew and spread, eight became six, and even less when the flower spikes were fully expanded.

To anchor the beds, we decided to use boxwood for its formal look and evergreen solidity, as well as for its amenability to being shaped. We chose the hybrid cultivar Buxus ‘Green Mountain” because it doesn’t bronze out in the winter (at least in our area). Eventually, we want the plants to take on a large gumdrop shape, four to five feet in height and almost as wide. This will most likely take ten years or more, as boxwood is relatively slow growing. When using plants in this formal manner, you need to prepare for the possibility of a gap if one or more of the plants die. That has happened here, and we have had to replace some of the original boxwoods with smaller specimens that will take several more years to catch up with the others. Overall, however, the boxwoods have settled in and lost that wan, “just planted” look, perhaps because we had some good soil brought in to supplement the site’s original lean, glacier-scraped soil.

For the hedging, we chose Lavandula angustifolia ‘Tucker’s Early Purple” for its decent winter foliage and profusion of flowers. This cultivar practically smothers itself in bloom! Despite its floral merits, it will most likely be supplanted by a newer variety of lavender—mainly because we want a cultivar with even better winter foliage.

BALANCING HARDSCAPE AND PLANTING Opposite: The main axial path is a full eight feet across, which allows two people to walk comfortably side by side. The exuberant, overflowing plantings keep the path from appearing too wide. Above: The garden’s sophisticated color scheme—typified here by blue catmint, purple alliums, and orange-salmon helianthemums and roses—gains much of its effectiveness by being tightly contained within a series of beds, each of which has an identical frame of lavender and boxwood.

THE “INFILL” PLANTINGS

With a few exceptions, we decided to use deciduous perennials for the infill planting, since we didn’t want evergreen perennials to crowd out and compete with the lavender hedge. As it is, it’s been difficult enough to keep the herbaceous material from swamping the lavender, and in a few spots the hedge has become spotty. Another lesson. At the clients” request, the color palette was limited to shades of blue, salmon through orange, yellow into chartreuse, and purple blending into lavender. No pinks or reds. (See the chart on pages 44–45 for a breakdown of the main perennials and their color groups.)

The infill has been designed to change and evolve, with no single plant or group of plants being “sacred.” In the winter, after the perennials have been cut back, the lavender and boxwood provide all the visual interest that’s needed, since the empty beds aren’t very noticeable from inside the house (and winter weather in the Pacific Northwest not being conducive to lingering long outdoors).

Although we repeated perennials within the various beds, each bed didn’t get the same number of each cultivar, nor were they evenly spaced. We wanted a somewhat cottagey effect, but with strong outlines and permanent anchor plants to keep the beds from becoming too blowsy.

Tulips and some minor bulbs such as lesser celandine (Ranunculus ficaria) and Scilla siberica start the show in spring, along with Lathyrus vernus, columbines, and primulas. Tulips usually don’t persist long in our area, and we plan to pull them out after they’ve dwindled. The early perennials we chose have the advantage that they will tolerate being swamped by their neighbors later in the summer, and won’t be seriously affected by the resulting lack of sunlight and poor air circulation.

4 Border Basics: Staying Flexible

After the initial spring bulbs go over, the alliums come on. Allium cristophii and A. ‘Globemaster” constitute one of the borders” main themes, and provide months of enjoyment. Even after the seed heads have faded into their tawny, post-bloom colors, they still contribute to the overall effect. Another subtle but pleasant detail has been supplied by the seed heads produced by certain of the tulips.

High on the list of desiderata for this garden—and in fact one of the most essential elements in any garden—was good foliage. This was supplied by Euphorbia wallichii, Ferula communis, and the variegated Phlox paniculata cultivars ‘Harlequin” and ‘Norah Leigh’, all of which come into their own after the spring ephemerals. Even when not in flower, plants like these can contribute interest for an entire season.

Hardy geraniums in shades of lavender blue form another major theme. We carefully chose the cultivars ‘Mayflower’, ‘Brookside’, ‘Spinners’, and ‘Amy Doncaster” to provide a sequence of bloom times. This has worked out well, and gives the garden a good three months of bloom. Over time, however, it became apparent that some of the geraniums were exceeding the dimensions stated in the catalogs. Every year, therefore, most of the geraniums get divided to keep them in scale with their neighbors. In the near future, it is likely that we will replace all the geraniums with G. ‘Rozanne’, an outstanding new, longblooming cultivar.

Constant editing has been essential to keep the borders in balance. Our climate is very conducive to plant growth, and certain perennials, like the geraniums, grow larger than elsewhere in the country. Other plants have experienced a dimming of their aesthetic qualities as they’ve aged. Both these phenomena have underscored the importance of a flexible palette that permits periodic substitutions.

FAILED EXPERIMENTS

Just as every border has its successes, so every border has its share of failures. If a border is to reach its full potential, it’s important to face both squarely. In the first growing season we planted Euphorbia dulcis ‘Chameleon” for its attractive chocolate-purple foliage. This proved to be a major mistake, as every seed the plants produced seemed to be viable. This euphorbia has also become susceptible to mildew in the Pacific Northwest. So out it went, along with a mislabeled eryngium, which also proved to be a vicious self-sower.

Kniphofias worked well for the first three years but eventually became too large and coarse. The flower colors were perfect, but the plants” “down time” (i.e., ugliness) seemed to increase with age. Two orange-apricot roses—‘Just Joey” and ‘Victor Borge’—took their place, thus preserving the color scheme but offering a longer season of bloom. It also goes without saying that any rose we use must have relatively clean foliage.

Rating the Self-Sowers

Be aware that a plant that is perfectly well behaved in one part of the country may turn into a monster where soil and climate are to its liking. Also, in larger gardens self-sowers tend to be less of a problem and may even help suppress weeds. The categories below reflect our experience in the Seattle area.

GOODAquilegia spp.: columbine species and hybrids come in a wide range of colors; stick to a single variety, otherwise they will interbreed and become muddy Astrantia spp.: perennial with shaggy flowers in red, pink, or white; shade tolerant Cerinthe major ‘Purpurascens’: biennial with handsome glaucous foliage and small purple flowers Euphorbia schillingii: strong-growing perennial spurge with chartreuse flower heads in late summer Lathyrus vernus: early-blooming perennial for partial shade with pink, rose, or blue pea flowers; a charmer

MAINTAINING SEASON-LONG INTEREST Opposite: Plants with outstanding foliage or structure—such as the clump of the variegated Phlox ‘Norah Leigh, just right of center—are as essential to the garden’s success as are the showy bloomers. Above: Even though most of the flowers are gone by late summer, there’s still plenty to please the eye: bleached allium seed heads, gray helianthemum foliage, lilac pink Phlox ‘Norah Leigh” and deep rose Phlox ‘Harlequin’, and of course the lavender hedge and boxwoods. The fig in the terra-cotta pot serves as a conveniently movable vertical accent.

POTENTIALLY PROBLEMATIC Arum italicum: marble-foliaged plants may interbreed with plain-leaved ones, resulting in drab offspring Campanula lactiflora: bears dense heads of handsome pale blue flowers, but may become a pest on heavy, rich soil Smilacina racemosa: a handsome native woodland perennial with plumelike ivory flowers; may self-seed too readily in some areas Tellima grandiflora: evergreen groundcover for shade with rounded, lobed leaves Thalictrum flavum subsp. glaucum: beautiful ferny glaucous foliage and fluffy lemon flowers: self-seeds ferociously

BAD Crocosmia xcrocosmiiflora: the familiar orange montbretia; a pest on much of the West Coast Euphorbia dulcis ‘Chameleon’: chocolate-colored foliage tends to mildew Eryngium planum: small, spiky, light blue flower heads; E. xtripartitum is far superior Foeniculum vulgare ‘Purpureum’: bronze fennel; beautiful but unstoppable unless rigorously deadheaded Geranium endressii: pink flowers, divided, light green leaves; seductive but evil Geranium xoxonianum: many selections with flowers in shades of pink; shows the same proclivities as G. endressii

4 Border Basics: Staying Flexible

Catmints (Nepeta spp.) proved to be somewhat problematic as well. One of their attractions—aside from their soft tints of bluish lavender—is that they offer repeat bloom in our climate if sheared back after their initial flowering. The selection we used, however, Nepeta racemosa ‘Walker’s Low’, proved to be misnamed—“low” it certainly isn’t. We’ve kept it, but under strict supervision, and it gets divided each spring.

AFTER THE BLOOM

The garden quiets down toward autumn, mainly because it’s too difficult to keep things in flower throughout the year in such a confined space. Provided the messier perennials are groomed or cut back, however, interesting juxtapositions of foliage keep the garden looking good even as it begins to decline. Some plants, such as the giant fennel, Eryngium alpinum, and E. bourgatii, don’t get deadheaded, as songbirds are atracted to the seeds in the waning months, Fall goes on for a long time in our climate, so at a certain point (usually in early November) we cut down the last of the tawdry perennials, thus leaving a clean slate for spring and for the cycle to begin again.

Above left: Allium cristophii, ‘Tucker’s Early Purple” lavender, hardy gemaiums, Eryngium bourgatii, and Achillea ‘Salmon Queen’. Above right: Helianthemum ‘Glenndolyn’, a new selection that is becoming popular in the Seattle area.

Main Infill Perennials by Color

NAME HEIGHT BLOOM PERIOD USDA ZONES DESCRIPTION
BLUE/LAVENDER
Allium cristophii 18–30 in. late spring/early summer 4–8 flower heads are 10-in. spheres of silvery lavender; seed heads very attractive
Allium ‘Globemaster’ 24–40 in. late spring/early summer 4–8 10-in. flower heads are a deeper purple than A. cristophii
Eryngium alpinum ‘Blue Star’ 24–30 in. midsummer 5–8 a select form of the species with deep blue stems and prickly, silvery blue calyxes
Eryngium amethystinum 24 in. midsummer 3–8 branched sterns bear many small silvery blue spiny flowers
Eryngium bourgatii 24 in. midsummer 5–9 handsome, deeply cut foliage is gray green with white veins; greenish blue, thistlelike flowr heads
Eryngium xzabelii ‘Donard Variety’ 24–30 in. late summer 5–9 hybrid of E. alpinum and E. bourgatii; large, long-lasting deep blue flower heads in July or August
Geranium ‘Brookside’ 18 in. midsummer 4–9 vigorous plant with bowl-shaped, deep blue flowers with a lighter throat
Geranium ‘Spinners’ 36 in. late spring-midsummer 4–9 very vigorous, upright plant with abundant deep purple-blue flowers
Geranium sylvaticum ‘Amy Doncaster’ 28 in. late spring 4–9 clump former; deep blue, white-eyed flowers; good foliage; bluest of the G. sylvaticum selections
Geranium sylvaticum ‘Mayflower’ 28 in. late spring 4–9 slightly lighter blue flowers than ‘Amy Doncaster’
Lathyrus vernus 6–12 in. late spring 4–9 bears finely divided foliage and abundant, small, bluish pink pea flowers; ‘Caeruleus” and ‘Cyaneus” are a deeper blue
Lavandula angustifolia ‘Tucker’s Early Purple’ 20–24 in. early summer 5–9 very heavy bloomer; flowers bright violet blue; gray-green foliage
Nepeta racemosa ‘Walker’s Low’ 15 in. early-late summer 5–9 produces large mounds of gray-green foliage; long season of lavender-blue flowers
Phlox paniculata ‘Harlequin’ 36–48 in. midsummer 3–9 bold, white-variegated foliage; violet-purple flowers
Phlox paniculata ‘Norah Leigh’ 36 in. midsummer 3–9 white-margined foliage; flowers pinker and paler than ‘Harlequin’
ORANGE/SALMON
Achillea ‘Salmon Queen’ 24 in. mid-late summer 3–9 salmon flowers that fade to pinkish cream
Helianthemum ‘Glenndolyn’ 8–12 in. early summer 5–10 new cultivar with gray foliage and single, soft orange flowers
Ranunculus ficaria, orange selections 4–8 in. spring 4–9 disappears in midsummer; foliage of some selections is handsomely patterned; single forms may self-sow
Rosa ‘Just Joey’ 4–5 ft. early summer-fall 5–10 somewhat sprawling hybrid tea with dark green foliage and large, clustered, fragrant, orange-apricot flowers
Rosa ‘Victor Borge’ 4 ft. early summer-fall 5–10 hybrid tea with shapely, salmon-orange flowers; repeats well
YELLOW/CHARTREUSE
Crocosmia ‘Solfatare’ 24 in. late summer 7–10 striking selection with bronze, swordlike foliage and apricot-yellow flowers
Crocosmia ‘Jenny Bloom’ 30 in. midsummer 5–10 swordlike green foliage; produces a profuse display of small, golden-yellow flowers
Euphorbia wallichii 18 in. early summer 6–9 dark green leaves have a white central vein; large, bright, yellow-green bracts
Ferula communis to 10 ft. midsummer 6–10 produces huge clumps of feathery foliage that disappear in midsummer; takes several years to bloom
Ranunculus ficaria, yellow selections 4–8 in. spring 4–9 numerous selections available, both single and double, from pale primrose to deep golden yellow

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