Bottlebrush buckeye flowers.

A mature bottlebrush buckeye can be up to 15 feet wide and 8 feet high. This specimen in Ann Arbor, Mich., is about 15 years old.

A buckeye leaf.

By Joseph Mooney
Native plant of the week: Bottlebrush buckeye, Aesculus parviflora
“What is that plant?” asks nearly everyone who sees bottlebrush buckeye, especially when this stately woody shrub is in bloom. In fact, this underappreciated native plant elicits commentary in almost every season. When in bloom, the 12-inch+ flower stalks resemble, yes, bottlebrushes. In fall, the leaves turn a rich golden yellow. And in summer, large compound leaves with five to seven leaflets extend from long petioles on branches that mound to a symmetrical hummock shape.
Native plant aficionados take note: while A. parviflora is native to the southeastern U.S., it grows well in zones 4-8. At Matthaei Botanical Gardens a large stand grows near the perennial garden, and a 15-year-old plant in the author’s garden continues to flourish in a somewhat dry shady spot and through the cruelest winters with no dieback whatsoever. Have you noticed the deer in SE Michigan? They walk on by bottlebrush in search of tastier things.

Unopened buckeye leaf flowers.

A single buckeye leaf flower stalk may be up to one foot long.

Bottlebrush buckeye produces pear-shaped fruits that contain poisonous seeds. The seeds of plants grown in more northerly locations are usually not viable. Photo by Jim Robbins.

Bottlebrush buckeye has many beautiful features, including its rich gold fall foliage. Photo by John Hagstrom.

Growing requirements for bottlebrush buckeye are generally full sun to part shade with soil that’s well-drained and moist. Bottlebrush buckeye grows slowly, but think carefully where you want to plant it. A. parviflora is a suckering plant and over time can form a large mound up to 12-15 feet wide and 7-8 feet tall. At Mt. Cuba Center in Hockessin, Delaware, some of their bottlebrush are nearly 15 feet tall. Nevertheless it is a slow grower and not considered invasive outside its native range.
In late summer pear-shaped fruits form but few seeds are viable from plants grown in northern climates (personal experience). Squirrels love the seeds, however, and one by one they disappear. Otherwise bottlebrush seeds are poisonous. Another great feature of A. parviflora is how it attracts solitary bees and butterflies. You’ll often see eastern tiger swallowtails, giant swallowtails, and monarchs on the same plant at the same time. Solitary bees love A. parviflora and are essential pollinators, plus they’re beautiful and fun to watch.
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