Photo: Krzysztof Ziarnek, CC BY-SA 4.0 · Wikimedia Commons

Bottlebrush Buckeye

Aesculus parviflora

Also called small-flowered buckeye, Aesculus macrostachya.

A shade shrub that spreads into a broad mound and lifts white flower spikes up to a foot long in early summer, when few other shrubs bloom.

Showy flowersTolerates shadeWildlife valueFall colorRareErosion control

Type: Shrub
Mature height: 8–12 ft
USDA zones: 4–9
Growth rate: Slow
Sun: Full, Part, Shade
Soil moisture: Average, Wet
Grows wild in: The forest understory, rich moist slopes, floodplain forests and stream banks
Native range: Alabama, Georgia and South Carolina Also recorded in 4 other states, outside its native range. See what is native in your state

Hardiness zones Find your zone by ZIP code

Bottlebrush buckeye is a suckering shrub that slowly widens into a mound, in time twice as broad as it is tall. It blooms in early summer, after the yellow and painted buckeyes we grow have finished, and it keeps its leaves in good shape well into fall, unlike most buckeyes. NatureServe ranks it vulnerable, since it grows wild in so few places. Farther north it grows wild only where it has escaped from gardens, as in Pennsylvania and New Jersey. Planted on eroding ground, it stabilizes the soil. Give it a big, shady corner under tall trees, where it can spread into a colony.

Size, growth and what to expect

Bottlebrush buckeye grows slowly, about a foot a year in our growth estimator. It grows 8 to 12 feet tall and 8 to 15 feet wide. It flowers in about 3 years from seed.

Upright spikes of small white flowers, up to 12 inches long, open in June and July. Long pinkish stamens with red anthers give them their bottlebrush look. Hummingbirds, bees and butterflies visit, eastern swallowtails among them. The smooth, pear-shaped husks split from late September into November, each holding a glossy brown seed with a pale scar. Each leaf has five to seven leaflets spread like the fingers of a hand, and they turn yellow in fall.

It grows wild in six counties of southwest Georgia and seven on Alabama's Cumberland Plateau, and near the Fall Line in South Carolina. Its home is rich, moist woods on bluffs, in ravines and on silty river flats.

How to grow Bottlebrush Buckeye

Bottlebrush buckeye does best in part shade or shade, in a rich, moist soil that drains well. It takes full sun where the soil stays moist, though the leaves can scorch. It will not take dry soil, above all while young. Plant it 8 feet from a wall and set plants 5 feet apart for a mass planting. At its size it can go within 15 feet of overhead wires.

Saplings ship potted. Plant them in the dormant season, in a hole wider than the pot and no deeper. Set the root flare at the soil line, put the native soil back in, and mulch a wide ring clear of the stems. Buckeye seed dies if it dries out, so sow it as soon as the husks split in fall. Set each seed an inch or two deep with the pale scar down. It roots that fall, and the shoot waits for spring.

Water weekly through the first two summers, and in hot, dry spells after that, to keep the leaves from wilting and scorching. Deer and rabbits seldom do it serious harm. It needs little pruning, and since it flowers on old wood, cut only right after bloom. An old, crowded plant can be cut hard in late winter to renew it.

Bottlebrush buckeye sets seed with its own pollen, so one plant can bear alone; bees and butterflies carry pollen from its many male flowers to the few with both parts. It rarely sets seed except after very hot, dry late summers. Plants in the North bear few fruits. Every part is poisonous if eaten, the nuts above all, so keep them from children and pets. No serious pest or disease troubles it.

Heights and zones are typical ranges for the species in cultivation; local conditions and seed source shift them.

Sources (13)