Troubleshooting
Aesculus hippocastanum problems — and how to fix them
Aesculus hippocastanum (Aesculus hippocastanum) is generally forgiving once you match its basics, but a few issues come up again and again. Here is what each one looks like, why it happens, and the fix.
Horse chestnut leaf miner
The moth Cameraria ohridella mines the leaves, turning them brown and crisp from midsummer; widespread and disfiguring but rarely fatal. Raking and binning fallen leaves reduces overwintering numbers.
Bleeding canker
A bacterial disease (Pseudomonas syringae pv. aesculi) causes dark, weeping cankers on the trunk and can be serious or fatal. There is no cure; avoid stressing trees and remove badly affected specimens.
Leaf scorch and blotch
Hot, dry summers and the fungal leaf blotch (Guignardia) both brown the leaf margins. Mulch and water young trees; the damage is mostly cosmetic late in the season.
Falling conkers and spiky cases
In autumn the heavy, prickly fruits drop and litter the ground, a hazard on paths and to pets that may eat them. Site away from walkways and clear fallen conkers.
Prevent aesculus hippocastanum problems before they start
Most aesculus hippocastanum issues are care-mismatch, not bad luck. Dial in the basics:
Looking for aesculus hippocastanum in general rather than its problems? Read the full aesculus hippocastanum care guide — light, water, soil and feeding.
Aesculus hippocastanum problems — FAQ
Why is my aesculus hippocastanum horse chestnut leaf miner?
The moth Cameraria ohridella mines the leaves, turning them brown and crisp from midsummer; widespread and disfiguring but rarely fatal. Raking and binning fallen leaves reduces overwintering numbers.
Why is my aesculus hippocastanum bleeding canker?
A bacterial disease (Pseudomonas syringae pv. aesculi) causes dark, weeping cankers on the trunk and can be serious or fatal. There is no cure; avoid stressing trees and remove badly affected specimens.
Why is my aesculus hippocastanum leaf scorch and blotch?
Hot, dry summers and the fungal leaf blotch (Guignardia) both brown the leaf margins. Mulch and water young trees; the damage is mostly cosmetic late in the season.
Why is my aesculus hippocastanum falling conkers and spiky cases?
In autumn the heavy, prickly fruits drop and litter the ground, a hazard on paths and to pets that may eat them. Site away from walkways and clear fallen conkers.