Chicago Botanic Garden

Chicago Botanic Garden Evaluates Meadow Rues

Plant Evaluation Notes Identifies Best Plants for Midwest

GLENCOE, Ill. (March 5, 2007) -- The Chicago Botanic Garden is releasing results of a nine-year study of Meadow Rues, Thalictrum, in its 28^th issue of Plant Evaluation Notes: “An Evaluation Report of Meadow Rues.”

Meadow rues are a diverse group of perennials well-suited to a variety of garden settings including sunny borders, woodlands and rockeries. The delicate airy flowers, handsome fernlike foliage and graceful habit of meadow rues make them a treasure in the garden. They are used formally or informally in borders, meadows and woodland gardens.

The Chicago Botanic Garden evaluated 26 taxa of Thalictrum from 1995 through 2003 to identify outstanding selections for full-sun gardens through an assessment of their flower production, plant health, habit quality and winter hardiness.

The easy-to-grow meadow rues generally prefer moist, organic soils in partial sun to full sun. In some cases, such as Thalictrum aquilegiifolium, consistent moisture is beneficial for success in sunny gardens. They are mostly trouble-free, although powdery mildew and leaf miners are occasional pest problems for some species.

In general, the meadow rues exhibited strong habits and good flower production in the full-sun test site. The lack of any serious pest or disease problems, combined with winter hardiness, contributed to high ratings for many plants. Eleven taxa received four-star good ratings for their overall performance, including Thalictrum flavum ssp. glaucum, T. flavum ‘Illuminator’, T. kiusianum, T. lucidum, T. minus ‘Adiantifolium’, T. pubescens, T. rochebruneanum, T. rochebruneanum ‘Lavender Mist’, T. rochebruneanum ‘Purple Mist’, T. ‘Elin’ and T. aquilegiifolium ‘Purpureum’.

Flowers of Thalictrum rochebruneanum feature prominent lavender sepals surrounding a cluster of yellow stamens. The persistent and colorful sepals set this species apart from many of the other taxa in the trial. Leaves emerged purple, eventually fading to blue-green by late May. It typically has a sparse or see-through quality to its habit. Stems remained upright all summer with secondary bloom noted in the lower leaf axils into September.

Linear leaflets differentiated Thalictrum lucidum from other meadow rues in the trial. The bi- to tri-ternately compound leaves emerged purple, eventually changing to lustrous green. This species put on an outstanding show in bloom, with puffs of pale yellow flowers in pyramidal clusters up to 9 inches wide. It had a robust habit with stems that remained upright all summer.

The Chicago Botanic Garden’s Plant Evaluation Notes provide the latest information on plants suited to the Midwestern climate and growing conditions. Cost is $3 per copy. To obtain Issue 28, “An Evaluation Report of Meadow Rues,” write to the following address:

Plant Evaluation Notes

c/o Richard Hawke

1000 Lake Cook Road

Glencoe, IL 60022

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Editors, please note: The Chicago Botanic Garden’s newsroom is online at www.chicagobotanic.org/pr. For digital images, contact Julie McCaffrey at (847) 835-8213 or at jmccaffrey@chicagobotanic.org.

The Chicago Botanic Garden is a 385-acre living plant museum featuring 23 distinct display gardens surrounded by lakes, as well as a prairie and woodlands. With events, programs and activities for all ages, the Garden is open every day of the year, except Dec. 25. Admission is free; select event fees apply. Parking is $15; free for members. On Tuesdays, senior citizens age 62 and older pay just $7 for parking. The Garden is located at 1000 Lake Cook Road in Glencoe, Ill. Visit www.chicagobotanic.org, or call (847) 835-5440 for seasonal hours, images of the Garden and commuter transportation information.

The Chicago Botanic Garden is owned by the Forest Preserve District of Cook County and managed by the Chicago Horticultural Society. It opened to the public in 1972 and is home to the Joseph Regenstein, Jr. School of the Chicago Botanic Garden, offering a broad array of adult classes in plant science, landscape design and gardening arts. The Center for Teaching and Learning brings the wonder of nature and plants to children, teens and teachers. Horticultural Therapy and Community Gardening provide nationally recognized community outreach and service programs. Through the Institutes of Plant Conservation and Ornamental Plant Research, Garden scientists work on plant conservation, research and environmental initiatives that have global impact. The Chicago Botanic Garden is accredited by the American Association of Museums and is a member of the American Public Gardens Association (APGA). In 2006, the Chicago Botanic Garden received the Award for Garden Excellence, given yearly by the APGA and Horticulture magazine to a public garden that exemplifies the highest standards of horticultural practices and has shown a commitment to supporting and demonstrating best gardening practices.