Horse Chestnut
Aesculus hippocastanum
Few gardens have the room for one, and its leaf troubles are hard to escape once it has any size.
- Type
- Tree · Perennial
- Botanical family
- Mixed / other
- Foliage color
- Green
- Flower color
- White
- Sunlight
- Full sun
- Feeding
- All-purpose balanced
- Frost tolerant
- Yes
- Flowering
- May
- Apr–May Bud Break
- May–Jun Flowering
- Jun–Oct Fruit Set
- Oct–Nov Leaf Fall
- Nov–Dec Winter Dormancy
- Jan–Apr Winter Dormancy
- Plant spacing
- 49 ft 3 in
- In-row spacing
- 49 ft 3 in
- Between rows
- 61 ft 6 in
- Square-foot density
- Not suited to SFG
- Root system
- Woody, shallow and far-reaching
- Working depth
- 12–24 in
- Can reach
- 4 ft down where the soil allows
- Spread
- 98–148 ft across, about 2–3× the width of the plant
Almost all of a tree’s roots are in the top two feet of soil, where the air is, and they run out well past the branch tips. The deep taproot most people picture belongs to the seedling; the tree grows out of it and spends the rest of its life spreading sideways instead.
The habit is Horse Chestnut’s own; the figures are what that habit usually comes to at this size, not a measurement of this species. Roots follow the soil either way: a compacted pan, a high water table or heavy clay stops them well short of any of it, and deep open ground lets them go further.
- Cats and dogs
- Recorded toxic
Recorded as toxic to cats and dogs by ASPCA.
The ASPCA files our genus as Buckeye, printing Aesculus spp. with Horse Chestnut among its own common names, and records it Toxic to Dogs and Toxic to Cats. The row names the genus rather than one member of it, so it reaches our Aesculus hippocastanum. Its separate Horse Chestnut row is Aesculus glabra, a different species, and the two rows trade common names in both directions. The Pet Poison Helpline page for this species names no animal, saying only companion animals and livestock.
Beneficial predators that hunt this plant's pests — grow their favourite flowers nearby to recruit them. companion plant
- Parasitic wasps Braconidae & TrichogrammaHunts Leaf miners
Tiny, stingless wasps that lay eggs in or on caterpillars, aphids, and moth eggs — the white cocoons riding a hornworm are their calling card, so leave that caterpillar be. Umbel flowers with shallow nectar keep the adults fuelled.
Bluebells, Wild Garlic, Foxgloves, Beech
Green-leaved trees, like this one.
The Cottage Garden Companion — the gardener's herbarium at cottagegardencompanion.com