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Who's Afraid Of Big Bold Perennials?
by Yvonne Cunnington
by Yvonne Cunnington

I am a garden writer and photographer living near Hamilton, Ont. My articles have appeared in Chatelaine, Canadian Living, Canadian Gardening and Gardening Life magazines. My book for beginner gardeners, Clueless in the Garden: A Guide for the Horticulturally Helpless (Key Porter Books) was published in 2003.

My husband and I tend a large country garden, which has been featured on TV’s Gardeners Journal and in Gardening Life magazine. We have had numerous bus tours visit our garden.

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September 22, 2002

Visitors to my garden often note how many large-sized perennials and ornamental grasses I grow. And invariably that comment is followed by the observation that I have the space and that such plants probably wouldn't work in smaller gardens.

Well, yes, and no. Gardening in the country does offer the opportunity to try plants that might hold back the faint of heart, but I think many of my favorite large plants wouldn't look out of place in a suburban garden, especially on a new lot where young trees and shrubs haven't made their mark yet.

Just because your space may be smaller, doesn't mean your plants have to be itsy-bitsy. Sometimes, the addition of one or two really bold plants can give your perennial garden the punch that's missing. If you're ready to try some big, knockout perennials, here are three of my favorites. As well as being gorgeous, they're easy to care for: I don't stake or deadhead them. The only job is cutting the dead foliage back after frost in the fall or if you prefer, in the spring.

I first came across Persicaria polymorpha about four or five years ago when I read in Horticulture magazine that the American plantsman Wolfgang Oehme (of Oehme Van Sweden landscape architecture fame) was raving about this great new plant, so, of course, I had to have it. It took me awhile to find it: Heritage Perennials is one source; see and is another.

A well-behaved member of the notorious knotweed family, P. polymorpha is non-spreading bushy perennial that grows as big as a small shrub - about 4 to 5 feet tall. In early June it gets large, fluffy, creamy-white flower plumes that stay in bloom to the end of July! When the white flowers fade, the stems of the plumes turn a pleasant wheat-like colour that echoes the colour of the flower plumes of Calamagrosis x acutiflora 'Karl Foerster' (feather reed grass), one of my favorite grasses. Spent flowers that look great mean no deadheading - that's another huge plus in my book.

My P. polymorpha thrive in full sun, but I have one in a shadier spot in the perennial border, and it's a little smaller than the others. Most sources list its hardiness as Zone 5, but nurseryman Tony Avent at Plant Delights ( lists it as hardy to USDA Zone 3. The only drawback to this plant: if you live in an area plagued by Japanese beetles, you may find that they munch on the leaves.

Rudbeckia nitida 'Herbstsonne' (hardy to Zone 3) - the German cultivar name means "autumn sun" - is a giant in the garden. I've measured it at almost seven feet tall. True to its name, it blooms in September and October.

Though my garden is situated in an open windy site, of the half a dozen 'Herbstsonne' plants in two different beds, none has ever needed staking, a garden job I tend to avoid. I have it growing in full sun (in part shade it may grow more lax and need staking). It's said to need good drainage, but seems to thrive in my heavy clay soil. The flowers are yellow with attractively drooping petals around central green disk and its pinnate leaves give it the common name of cutleaf coneflower.

Joe Pye weed is another of my favorite bold perennials, though I hate the 'weed' part of its common name. This is a fabulous North American native perennial, hardy to Zone 4, and not the least bit weedy - I prefer to use its botanical name, Eupatorium. The cultivar I grow is Eupatorium fistulosum 'Selection' (sometimes labeled 'Select'). It's the architectural star of the late summer garden, growing 5 to 6 feet tall with huge flat long-blooming rosy-lavender flowerheads that attract butterflies and hummingbirds.

Some of my plants are in full sun and others are in part shade and both are thriving. In their native habitat, Eupatorium species are usually found in moist, even wet, soils, but this one, like other garden cultivars such as E. maculatum 'Gateway', does well in average garden soils, as long as it doesn't dry out.

So why not give big bold plants a try in your garden? And if you're wondering what to plant with them, each of these perennials marries well with ornamental grasses, such as Karl Foerster's feather reed grass, tall moor grass (Molinia 'Skyracer'), and cultivars of Miscanthus or Panicum virgatum.

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