Grow and Care for Buckeye

Grow buckeye and horse chestnut in sun to part shade with moist, fertile soil that drains. Buckeye is Aesculus — a deciduous tree or large shrub with palmate leaves and spring flower panicles, not an edible chestnut.

Give it sun to part shade and moist soil that drains

Buckeye is an understory tree in rich woods, so the root zone wants moisture it can drain. Compacted new-construction soil and a dry summer lawn are the main reasons leaves scorch and drop early. [1] [2] yellow buckeye still wants that moist drain, even though blotch bothers it less. Match size and light on Types of Buckeye.

Water a new tree through the first season

A new buckeye needs water so roots move out of the nursery ball. An established tree handles short dry spells better, but a long hot stretch still scorches the outer leaves.

1. Soak the root zone after you plant. Check a few inches down and water again when that soil starts to dry, not on a fixed calendar.
2. Keep the root zone moist — not soggy — through the first full growing season. A slow soak is more useful than a brief splash every day.
3. Once the tree is established, water during extended dry periods. Stop if soil below the surface is still wet.
4. Mulch about two inches over the root zone to hold moisture. Keep the mulch a few inches off the trunk so the bark stays dry.

Prune little, in late winter, and leave the lower limbs

Buckeye and horse chestnut need little pruning once the form is set. Late winter, before the buds open, is the usual window.

1. Wait until late winter. You can see the branch structure, and the tree is still dormant.
2. Cut out dead, damaged, or crossing wood. On a young tree, keep one main leader if the top has split into two.
3. Leave the lower limbs on Ohio buckeye unless they are dead or in the way of a walk. Those limbs are part of the natural rounded crown.
4. Do not top a mature horse chestnut, and do not cut large live limbs you can leave. Big wounds on this genus close slowly and invite decay.

Bottlebrush buckeye is a shrub. If the colony has run past the bed, cut unwanted suckers at the ground in late winter and stay on this light prune — do not shear it like a hedge.

Leaves turn brown in midsummer — drought scorch or leaf blotch

Two different problems brown buckeye and horse chestnut in midsummer. Both look alarming on an established tree, and neither is usually fatal.

Drought scorch starts at leaf margins and tips on the sunny or windward side of the canopy. Leaves inside the crown stay greener longer. The root zone ran dry in heat. Water deeply and keep the mulch in place; the tree leafs out normally the next spring.

Guignardia leaf blotch shows as reddish-brown patches with a bright yellow margin, scattered through the whole canopy, not only the sunny side. The spots show on both faces of the leaflet. [3] Infected leaves may drop by late summer, but the buds stay alive. Rake and bag fallen leaves in autumn so spores do not splash onto new growth. Do not reach for a spray on a large landscape tree — the disease is cosmetic.

If the tag is California buckeye, bare branches in July can be summer rest, not scorch. Pick that kind on Types of Buckeye.

Not an edible chestnut — buckeye and horse chestnut are Aesculus

Buckeye and horse chestnut belong to Aesculus. Edible chestnut belongs to Castanea. They are in different families, and the nuts are not interchangeable.

• Aesculus (buckeye and horse chestnut) — palmate compound leaves with 5–7 leaflets from one stalk; a round nut in a fleshy, sparsely spined husk; all parts toxic, including the nut.
• Castanea (sweet chestnut) — simple toothed leaves; an edible nut inside a densely spiny bur with a small point or tassel at the tip.

Do not eat buckeye nuts or horse chestnuts. Aesculin and saponins cause stomach upset and, in larger amounts, weakness. Squirrels cache the nuts; people, dogs, cats, and horses should not. [4] Rake fallen nuts where pets play.

If the outer leaves brown in July, soak the root zone once, then wait — a new tree almost always traces that scorch to a dry week.