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The Homeowners Column
Chicago Botanic Garden Evaluation Trials
Extension Educator, Horticulture
Garden catalogs are filling mail boxes with vivid pictures of magnificent flowers. For a new gardener it can be particularly alluring and overwhelming. How do you know if that plant is going to look good and survive in your garden? You can ask friends, family, Master Gardeners and the guy next to you in the checkout lane at the garden center. But wouldn't it be nice if someone planted similar plants in an Illinois garden and evaluated them over several years? Sort of like Consumer Reports for plants without the test dummy. The Chicago Botanic Garden heard and responded to the lamentations of the gardeners.
Since 1982 Chicago Botanic Garden Plant Evaluations program has scientifically evaluated perennials, vines, annuals, shrubs and trees for their adaptability to the Midwest. Their Plant Evaluation Program is one of the largest and most diverse in the United States. It is also one of the few U.S. programs that formally evaluates perennials.
Richard Hawke is the manager of the Plant Evaluations program and has been a part of the trials for 18 years. I recently heard Mr. Hawke speak at a program at the Botanic Garden. He is one of those people that has a discerning scientific eye but also truly loves plants.
Perennials are trialed for at least four years and receive little extra care. Evaluations include several characteristics such as winter hardiness, insect and disease problems, plant size, flower size, length of flowering, number of flowers and how well the flowers cover the plant. Not every garden is going to have the same environmental conditions as Botanic Garden but their trials sure give us a better understanding of perennials.
In the program I attended Hawke offered a word of caution about a couple plants. Coreopsis 'Limerock Ruby' is a beautiful plant sold as a perennial but has proven not be winter hardy here. Artemesia 'Oriental Limelight' is hardy but a very aggressive spreader. The trials pick out the good, the bad and the ugly.
Some of Hawke's favorite perennials from the Chicago Botanic Gardens Trials:
For sunny sites
- 'Angelique' yarrow (Achillea) is best of the dark red yarrows. At 24-30 inches tall it stays upright. A comparable yarrow 'Red Velvet' has a tendency to flop over. Floppiness is a good attribute only with bunnies.
- 'Brookside' geranium is a top performer and also one of my favorites. The deep blue flowers appear late May to mid August. It has a nice burgundy fall color. Good news it stays upright. Like many perennial geraniums it should be cut back after bloom.
- 'Marshall's Delight' beebalm (Monarda) gets 3-4 feet tall and rated as one of the best pink beebalms. It shows good resistance to powdery mildew, a fungal disease that makes the leaves unsightly.
For shady sites
- 'White Cloud' coral bells (Heuchera sanguinea) has clear green leaves and a nice white flower show. At only 9 inches tall it's a real cutie for front of the border.
- At the other extreme is 'Elin' meadowrue (Thalictrum hybrid). It gets a whopping 9 feet tall with lovely blue green leaves. The new growth is purple.
- 'Gold Heart' bleeding heart (Dicentra spectabilis) as its name implies has golden leaves that really stand out in a shady garden.
For a ground cover in sun or shade Hawke mentioned 'Shell Pink' and 'Beedham's White' deadnettle (Lamium maculatum).
For more top picks from Chicago Botanic Garden Trials you can go to their website http://www.chicagobotanic.org/research/research/index.html
After each study, Hawke publishes The Plant Evaluation Notes with extensive information about each trial. Notes are available for $3 per issue through the Plant Evaluation Program, 1000 Lake Cook Road, Glencoe, IL 60022. Phone: 847.835.5440. Make a note to visit the trial gardens next year.