Good to Grow: Chicago plant evaluator puts perennials through condition trials

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Good to Grow: Chicago plant evaluator puts perennials through condition trials

The Chicago Botanic Garden’s plant evaluation garden offers hope and inspiration for gardeners. Wouldn’t you love to know which perennials will thrive in your garden, returning year after year to produce copious long-lasting blooms? In 40 years of gardening, I can’t begin to imagine how many of my plants have disappeared or have been relegated to the compost heap for poor performance. If you visit the Chicago area, you can check out the Chicago Botanic Garden’s plant evaluation area, which I did on a trip to the Windy City almost four years ago. There, Richard Hawke, plant evaluation manager, puts perennials, woody shrubs and green roof plants through their paces. Those of us who attended the West Virginia Nursery & Landscape Association Symposium in January were lucky to hear Hawke speak and give us the scoop on perennials that have stood up well during a four-year trial period. Perennials in the test garden are grown in clay soil, sun and wind, with very cold temperatures in winter and heat in summer. They are not divided or fertilized and get no insect or disease control. Because it is a display garden, it is kept weeded and is irrigated with overhead watering. Soil pH is around 7.2, much more alkaline than ours, which hovers around 6.0, slightly acidic (7.0 is considered neutral, with numbers above that alkaline and numbers below acidic). As Hawke took us through a number of gorgeous plant images, his comments on some were enlightening. Have you regularly lost gorgeous new varieties of coneflowers, as I have? Hawke told us he’s discovered if a coneflower goes into winter without much basal foliage (leaves that grow close to the ground), it will probably die during the winter. He recommended “Pica Bella,” a pink-flowered, compact, reliably hardy coneflower variety. He also likes the native Tennessee coneflower, a tough plant that has the peculiar habit of facing east when it’s in bloom. Do your perennial hibiscus bloom only at the stem tips? If you want flowers all over the plant, try “Jazzberry Jam.” Its 9-inch-wide blossoms cover the 4-foot plant from mid-summer to fall. How about a tall garden phlox that’s resistant to powdery mildew, a disease that coats its leaves in an unattractive silver by late summer? Hawke recommended “Shortwood” as the most disease resistant variety. What about a dianthus that doesn’t rot during prolonged spells of wet weather? “Paint the Town” fits the bill and has a long bloom season. If you love black-eyed Susans (and who doesn’t?), Hawke said “American Gold Rush Everlasting Sun” is not just his favorite rudbeckia, it’s one of his favorite perennials. Why? A great pollinator plant, it is upright and naturally compact, reaching about 30 inches tall. It has a long season of bloom from July to the end of October and no leaf-spot problems. Sounds like a plant I’ll want to track down this spring. I also learned that one of my new favorite plants, “Blue Ice Bluestar,” will spread by underground […]