Yellow Buckeye

(Hippocastanaceae - Horsechestnut Family)

Form

• large shade tree, briefly doubling as a large ornamental tree
• maturing at about 75' tall by 40' wide
• upright oval growth habit
• medium growth rate

Culture

• full sun to partial sun (partial shade tolerant in youth)
• performs best in full sun in moist, rich, well-drained, deep, and slightly acidic soils; like most Buckeyes, it performs poorly in poor soils, clay soils, dry soils, and in polluted areas, and is somewhat tolerant of neutral to alkaline pH soils and tolerates briefly wet soils, but Yellow Buckeye tolerates urban stresses much better than other Buckeyes or Horsechestnuts, and as such makes the best member of the genus Aesculus to plant in urban areas as a shade tree
• propagated primarily by seeds
• Horsechestnut Family, with the same diseases (especially leaf spot, leaf blotch, leaf scorch, and powdery mildew) and pests that affect members of the genus Aesculus, but much reduced in the degree of infection or infestation, and as a result by Summer's end the foliage and stems appear reasonably healthy and dark green, as opposed to other members of the genus, which are often unsightly or defoliated
• low availability, in ball and burlap or container form

Foliage

• medium to dark green, opposite, and palmately compound with five (sometimes seven) leaflets
• leaflets are elliptical to obovate, acuminate, finely serrated, and with short petiolules
• not nearly as susceptible to unsightly leaf scorch, leaf spot, leaf blotch, and powdery mildew as other Aesculus
• fall color is a subdued yellow-orange to yellow-brown

Flowers

• yellow-green inflorescence is about 7" long by 3" wide, composed of an upright panicle of many solitary flowers, occuring in mid-May, with the inflorescence rising clearly above the expanded foliage

Fruits

• light brown, smooth, obovate capsules split open in September or October to generally yield two, 2" wide brown nuts with a prominent white "buck eye"

Twigs

• gray stout stems have prominent brown leaf scars, with the lateral buds being much smaller than the terminal bud(s)
• gray branches become rough or lightly furrowed with age

Trunk

• dark gray to brown, furrowed and ridged in middle age but becoming scaly and platy with maturity

ID Summary

• the following applies to Yellow Buckeye:
  • five (to seven) leaflets with short petiolules in palmately compound fashion compose the medium to dark green leaves, which do not get the degree of cosmetic unsightliness to their foliage by season's end as do most other Aesculus
  • yellow-green panicles of inflorescences in early May create a canopy of spire-like projections above the expanded medium-green foliage
  • fruit husks are smooth, and usually contain two nuts (sometimes one nut) with the typical "buck eye" appearance and shape
  • trunks are gray-brown and scaly to platy with age, supporting the upright oval canopy that spreads relatively little with age (to 75' tall by 40' wide)
• even though most Yellow Buckeyes are taller at maturity, with a more rapid growth rate and being much less common in the wild, it is very difficult to distinguish them with certainty from Ohio Buckeye for trees under 50' tall from October through July, unless the dehiscing fruits are present, whereby the two nuts per capsule can be distinguished from the one nut per capsule that is present on Ohio Buckeye, or unless the late Summer foliage is present, which is typically in much better shape for Yellow Buckeye; even then, everything is relative and identification with certainty is difficult

USAGE

Function

• shade tree, doubling as an ornamental tree in early May

Texture

• medium-bold texture in foliage and when bare
• thick density in foliage and average density when bare

Assets

• stately shade tree with prominent inflorescences in mid-Spring
• not as prone to unsightly foliage diseases or pest damage, or early defoliation, as are other Buckeyes and Horsechestnuts

Liabilities

• slight amount of cosmetic leaf unsightliness in mid- to late-Summer
• fruit litter in early Autumn

Habitat

• zones 3 to 8
• native to the Eastern United States

SELECTIONS

Alternates

• large shade trees that have showy flowers (Aesculus x carnea, Aesculus glabra, Aesculus hippocastanum, Liriodendron tulipifera, Magnolia grandiflora, etc.)
• large trees with nuts that attract wildlife (members of the genera Aesculus, Carya, Castanea, Corylus, Fagus, Juglans, Quercus, etc.)

Variants

• species form is the available choice

NOTES

Translation

• Aesculus is another of the classical names for an Oak tree.
• octandra translates as "with eight stamens", referring to the pollen-bearing structures.
• formerly known as Aesculus flava, where the specific epithet translates as "yellow", referring to the floral color.

Purpose

• Yellow Buckeye is the best of the shade tree Buckeyes and Horsechestnuts, with respect to its relatively clean foliage by Summer's end.

Summary

• Aesculus octandra is known for its tall stately growth habit, prominent yellow inflorescences in Spring, clean Summer foliage, and fruits in Autumn.