perennial garden

Claudia West - a wondrous and enthusiastic horticulturalist with important ideas

Rainer and West.jpg

“ It’s very simple, I usually say: Plant more of the right kinds of plants. Replace the mulch with more ecological plants—meaning native and beneficial exotic species—that will dramatically help in creating better cities. Plant more plants!” – Quote from Claudia West

Thomas Rainer Planting Design

Thomas Rainer Planting Design

Claudia West is a particularly talented and effusive horticulturalist who is also a scientist and a great speaker. She spoke at the New York Botanical Garden two winters ago and gave the audience a lot of memorable “catchphrases” – most prominently “Plants Cover Ground” – say it with me, as she said, “Plants Cover Ground”. She explains her thinking in some of the book-tour-related interviews she’s given as well:

“Plants are really the best mulch on earth. Don’t get me wrong, we’re not against using mulch at all, but mulch should only be temporary in your garden, to fill gaps between plants until they are more established… [to] suppress maybe an early wave of sun-loving weed species. But then we really want plants to grow in as they can and cover that soil on their own. So really the best and most sustainable way of gardening is letting plants be the mulch that they’re designed to be. This is how nature works, this is how plants want to grow—that’s how they evolved to grow—and it definitely works way better.”

Perhaps the greatest challenge facing landscape designers today is the need to balance beauty with environmental concerns. Public institutions and private homeowners want plantings that please the eye and reconnect us to nature, but that also reduce chemical use, filter stormwater, sequester pollutants and carbon, cool urban temperatures, and provide habitat. The answer lies in a radical turn away from conventional horticultural practices, declare landscape architect Thomas Rainer and designer Claudia West, who advocate crafting communities of compatible species that will cover the ground in interlocking layers. – “Designing Plant Communities for Resilient Landscapes” is the subtitle of their book, Planting in a Post-Wild World published in 2015. It has been described by leading industry experts as a “game-changer” and “the universal how-to guide to sustainable landscaping.”

From the Washington Post

Why manicured lawns should become a thing of the past

By Adrian Higgins December 2, 2015

Many folks, not to mention homeowners associations, cling to that model of the American yard as one of clipped foundation shrubs, groomed lawns and trees with mulch circles. Naked soil must be blanketed spring and fall with shredded mulch. Fallen leaves are treated as trash.

The real gardening world left this fusty model years ago, embracing soft groupings of perennials, grasses and specimen trees and shrubs in a celebration of plants and a closer communion with nature.

…This premise is not entirely new: A generation ago, top designers were espousing “the New American Garden” with many of the same principles, of replacing lawns and shrubbery with perennials and ornamental grasses.

What has changed at the vanguard of garden design? Many more varieties of perennials are widely available now than in the 1990s and, moreover, the approach to planting design is changing fundamentally. Rainer, West and others are promoting a shift from clumping and grouping plant varieties to mixing them in a way that occurs in nature. Discrete clumps are replaced with interplanted varieties equipped by nature to live cheek by jowl.

“The key is to pay attention to how plants fit together,” Rainer said. “To pay attention to their shape and behavior.” This involves not only their growth patterns aboveground, but their root types, which permit plants that are surface-rooted, such as many ground covers, to coexist with deep-rooted meadow flowers and grasses.

They see the garden as no longer a collection of plants but rather a designed plant community. This is distilled into three layers. In a sunny, meadow-like garden, the uppermost layer takes the form of beefier structural perennials …(and ornamental grasses). The middle layer is the showiest and provides seasonal peaks with such things as daisies, daylilies, butterfly weeds or bee balms.

The most important layer, the ground cover, is the least showy. Forget tired spreads of English ivy or pachysandra; Rainer and West are thinking of sedges, small grasses, rushes. In shade gardens, the floor layer would consist of such woodland beauties as foamflower, trilliums, gingers and Allegheny spurge.

“The approach to ground cover is, for us, the single most important concept of creating a functioning plant community,” they write. “Think about seeing plants in the wild; there is almost never bare soil.”

The ground cover not only knits together the whole plant community physically and emotionally, but also performs an important horticultural function. Soil left bare will invite weeds, so we smother it in mulch, which has its value, but we keep piling it on for aesthetic rather than horticultural reasons. This is inherently unsustainable and expensive, and keeps lonely plantings in a perpetual state of establishment.

My theme for 2018 is to highlight different “groundcovers” – meaning plants that will spread to cover bare ground but will still co-exist happily with the rest of the plants in the community. As Roy Diblik says: “they share the space unselfishly”.


Pycnanthemum muticum (Short-toothed Mountain Mint)

is an aromatic perennial wildflower. This mint relative bears oval toothed leaves on strong square stems. Butterflies and other pollinators love mountain mint. It is excellent at providing soil stabilization as well. In summer, plants are topped by dense rounded clusters of tiny white to lavender tubular flowers. The leaves surrounding the flower clusters are highlighted with silver. (Note: some people don’t like this look). Pollinators flock to the blooms in sunny gardens with average well drained soils.

Plants tolerate clay, heat and drought.

The aromatic foliage is unpalatable to deer, rabbits and other herbivores.

This rhizomatous species will ramble and expand to form colonies. The rhizomes are shallow, though, so unwanted plants are easy to pull.

Plants are hardy from USDA Zones 4-8.

Blooming lasts for about 6 weeks

Plants grow 2-3’ tall with 2’ spread.

The mountain mints are listed on many “Top Ten Plants for Pollinators” list. The dense head-like flower cymes make this plant a pollinator paradise. Native bees, beneficial wasps, flies, beetles, skippers and small butterflies (especially hairstreaks) frequent the blossoms.

In the 2013 Penn State Extension Service Pollinator Trial “88 pollinator-rewarding herbaceous perennial plants were assessed and promoted to growers, landscapers, nursery operators, and homeowners...” Pycnanthemum muticum was rated #1 for longevity of flowers and #1 for diversity of pollinators. It also attracted the greatest number of insects of any plant. During a 2 minute time period, 78 insects visited Pycnanthemum muticum including 19 bees and syrphid flies.

Salvia verticiliata ‘Endless Love’ (Endless Love Lilac Sage)

is an outstanding selection of this Old World native sage grown for its big, fuzzy, deep-green leaves and summer-long display of large, lavender-purple flower spikes. This is a distinctive sage and very different from the nemerosa types. This superb cultivar was introduced by European plantsman Piet Oudolf.

24" tall x 30-36" wide.

Hardy in zones 5 to 9

Deer resistant, bee friendly, rabbit resistant

Full sun or Morning sun and part shade afternoon

Will rebloom if spent flowers are clipped

Stachys monieri 'Hummelo' (Betony; sometimes also Lamb’s Ear)

Excellent for flowers and foliage, S. 'Hummelo' hosts a lovely display of lavender-purple flowers atop tall, leafless stems while the stoloniferous nature creates small mounding clumps. Selected for strong flower production, plant health, habit quality and winter hardiness. A true garden delight! And a Piet Oudolf introduction and staple of many of his gardens.

Spread 18 inches

Height 18-20 inches

USDA Hardiness Zone 4-8

Deer-resistant, full sun or part shade, used as a groundcover

Unlike Stachys byzantina (Lamb's Ear), this species forms large, rounded clumps of green, long and narrow, textured leaves. It is lovely even when it's not in bloom. From early thru midsummer, sturdy spikes of lavender-rose flowers shoot up through the foliage, putting on quite a display.

Though this plant is relatively unknown to many gardeners, it makes a unique addition to any sunny border. Once you try it, you'll see that it goes with just about everything else in the garden. It is very easy to grow and deserves to be planted more widely in American landscapes.

Stachys m. 'Hummelo' received the highest rating out of 22 Stachys studied in the Plant Evaluation Trials at the Chicago Botanic Garden. The trial was run from 1998-2004 by Richard G. Hawke. Both 'Helene von Stein' (aka 'Big Ears') and 'Silver Carpet' (the fuzzy silver-foliaged “Lamb’s Ear” that we’re probably more familiar with) also received very high scores.

2015 Perennial Plant of the Year - Geranium x cantabrigiense 'Biokovo'

Geranium X cantabrigiense 'Biokovo' in flower

The Perennial Plant Association membership has voted and the 2015 Perennial Plant of the Year™ is  Geranium X cantabrigiense ‘Biokovo’.

 ’Biokovo’ is a naturally occurring hybrid of Geranium dalmaticum and Geranium macrorrhizum found in the Dalmatia region of present-day Croatia.  It blooms in late spring with masses of 5-petaled white flowers, about ¾” diameter, that are tinged pink at the base of each petal and have darker pink center stamens.  An interesting feature is that the sepals that are redder than the petals, so that when the flower opens the lightly tinged pink flowers provide a nice contrast to the sepals and stamens.  It blooms from mid-May to late July.

G. X cantabrigiense has aromatic foliage and rounded leaf edges and is semi-evergreen in most climates.  It has a spreading habit and is rhizomatous, i.e. it spreads by sending out runners.  It grows to 6-10 inches high, with a spread of about 2 feet.  It can be used as a ground cover that spreads fairly rapidly through the perennial bed or as an edger in the front of the border.  It also does well in rock gardens.  It tolerates full sun to part-shade conditions.  Its foliage turns scarlet and orange in the fall. 

Another G. X cantabrigiense variety is 'Karmina', because sometimes it matters what color the flowers are!

Geranium X cantabrigiense 'Karmina', seen below, has carmine-red flowers.

The general qualities of Geranium species (commone name "cranesbill") include: 

  • Deer Resistant (OK, yes, nothing is completely deer-resistant; it is in many places I've planted it)
  • Many varieties tolerate some shade
  • Bloom for 4 weeks or more 
  • Rabbit Resistant (again, it depends, but in general they leave it alone)
  • Flowers attract butterflies
  • Can be used as groundcovers (low spreaders) or bed-fillers (taller varieties)
  • Need little care and no division
  • Excellent mounding habit as they first start in spring, and some varieties maintain that habit.  
  • Deeply cut foliage; flowers with interesting veining patterns. 
  • They can be deadheaded after blooming, or the tops of the plants can be sheared back to new growth to stimulate re-bloom and freshen foliage.  
  • Many varieties have beautiful red, burgundy or orange fall color that is a stand-out if the plant has been allowed to weave intself throught the garden bed.

Other types of geranium that are useful in different garden contexts, are hardy and fairly care-free include:

  • Geranium macrorrhizum (Bigroot Geranium), Z 3-8, 15-18" in height, native to southern Europe, large laromatic leaves.  Varieties include 'Bevan's Variety' and 'Ingwersen's Variety', seen in the series of pictures below:

G. macrorrhizum 'Bevan's Variety'

G. macrorrhizhum 'Ingwersen's Variety'

G. macrorrhizum fall foliage color

  • Geranium pratense (Meadow Cranesbill), Z 5-7, 24-36" tall, purple flowers from reddish veins on dark blue petals, native to northern Europe, may need staking.  Some cultivars have dark foliage; need sun for optimal foliage color.   Clump-former; blooms May – July.  Cultivars include 'Dark Reiter',  'Midnight Reiter', 'Summer Skies', 'Purple Haze', 'Mrs. Kendall Clark', 'Splish Splash'.  G. praetense does spread by seed, so it can pop up here and there throughout the garden - that may be a desirable trait if you're trying to get it to fill in, or an undesirable trait if you only want it in a certain place.

G. praetense 'Midnight Reiter'

  • Geranium sanguineum (Bloody Cranesbill) Z 3-8, 9-12", magenta flowers in spring, native to Europe and Asia, tolerates heat and drought; deeply divided leaves, bright red fall color, blooms in spring.  Varieties include 'Striatum', 'Max Frei', 'Ankum's Pride'.

G. sanguineum 'Max Frei'

  • Geranium wlassovianum Z 5-8, 18-24" tall; One of the first hardy Geraniums to bloom and one of the last to stop. Dusky violet flowers with deeper veining and a white eye. Fall brings outstanding deep red tones. Trails gently.  Will adapt to most soil conditions provided there is good drainage and some moisture. Nice massed as a groundcover, in rock gardens or as an informal edger. Completely carefree.

G. wlassovianumG. wlassovianum fall foliage color

  •  And, of course, Geranium X 'Rozeanne' seen below.  Unbelievable quantities of large, violet-blue blooms from June until frost; hardy to Z5; 20" tall with a 2 foot spread; bluish-purple flowers are heightened by black anthers, magenta veins and a radiant white eye. Fiery red leaves in autumn; withstands sunny, hot sites and is happy just about anywhere, from an exposed border to a container.  'Rozeanne' is a naturally occurring sterile hybrid of Geranium himalayense and Geranium wallichianum ‘Buxton’s Variety’.  Lynden Miller says "No garden should be without Geranium 'Rozeanne'."