Eupatorium maculatum, or Joe-Pye Weed, is native to the Eastern and Central United States. It is a coarse, clumping perennial with a whorled leaf arrangement bearing 3-6 lanceolate leaves at each node. In nature, they will reach 4-6 feet (1-2 m) in height by about 3 foot (1 m) wide. Grown in a container, they usually reach 2-4 feet (60-120 cm) tall. Grown outdoors, they are a very showy tall border plant and are hardy in USDA zones 5-9.
Blooming Time: In late July to early September, the plants are adorned with light purple flowers in terminal corymbs. Individual corymbs may reach up to 8 inches (20 cm) across. The flowers are lightly scented and they are very showy when planted in mass plantings.
Culture: Eupatorium maculatum need full sun to partial shade with a moist rich soil mix. In the greenhouse, we use a soil mix consisting of 2 parts peat moss to 2 parts loam to 1 part sand or perlite. To this mixture, we add 1 cup of agricultural lime to each .01 cu yards of soil mix. The plants are kept moist for optimum growth and they are fertilized on a weekly basis using a balanced fertilizer diluted to ½ the strength recommended on the label. In late September, we start to restrict water and move the plants to a cooler environment to start the plants into dormancy. After the plants enter dormancy, they are cut back and stored at 48° F (9°C) until late March, when they are moved out of cold storage and introduced back into the greenhouse.
Propagation: Eupatorium maculatum are propagated by division of older plants and by seed in the spring. Seed germinates in 30-90 days at 55° F (12°C).
Eupatorium maculatum was featured as Plant of the Week August 8-14, 2003.
Guide to Past Plants-of-the-Week:
Cal's Plant of the Week was provided as a service by the University of Oklahoma Department of Microbiology & Plant Biology and specifically the late Cal Lemke, who used to be OU's botany greenhouse grower and an avid gardener at home as well. If the above links don't work, then try the overview site. You may also like to look at the thumbnail index. ©1998-2012 All rights reserved.