White flowers emerge on seven-son shrubs in late summer.
Bright red sepals color seven-son flower in fall.
Heptacodium miconioides or seven-son flower is new to most Minnesota gardeners. Sometimes called a crapemyrtle for the north, it is a large shrub with attractive peeling bark and late-summer blooms. When freezing temperatures evade our region until late fall, bright red calyxes develop, which offer further interest. Heptacodium is adaptable, but it prefers a sunny location and well-drained, neutral or acid soil.
Although sometimes listed as hardy only to USDA Zone 5, the Minnesota Landscape Arboretum in USDA Zone 4 has been growing seven-son flower in an exposed location for several years. Healthy specimens in Duluth, Minn., and reports of plants growing in International Falls, suggest that it is worth trying throughout the state.
Common Name: Seven-son flower
Botanical Name: Heptacodium miconioides
Type: Large shrub
Size: 15 feet high and 10 feet wide.
Soil: Well drained soil. Textures from sand to clay. Neutral to acid pH.
Exposure: Full sun is best. Some shade is tolerated.
Watering: Water regularly until established. Performs well on average rainfall in normal years.
When to fertilize: At time of bud-break in spring.
Hardiness: Worth trialing in USDA Zones 3 and 4.
Planting: Break up root ball at time of planting.
Pruning: Remove broken or dead canes. Training heptacodium as a tree is not recommended.
In your landscape: Heptacodium is excellent in a shrub border or as a focal point in a mixed border. Its late-season flowers and attractive bark provide interest in fall and winter.
From Minnesota Gardener Volume I Issue IV. Photos courtesy of Spring Meadow Nursery.