Invasive plants and tree disease
Honey fungus: confirm it and what it means for your garden
Honey fungus is a group of fungi that spread underground and kill the roots and base of trees, shrubs and woody plants. Tell-tale signs are a white fungal sheet under the bark at the base, and black bootlace-like strands in the soil. There is no chemical cure, so control means removing infected material and choosing resistant plants.
- Also known as
- Armillaria, bootlace fungus
- Easily confused with
- other root and butt rots, drought or waterlogging dieback, other bracket fungi
- How serious
- High for woody plants: no chemical cure, spreads underground
- Typical cost
- Tree felling and stump removal are priced by size and access; diagnosis and replanting advice cost less
How to identify honey fungus
The RHS describes the most reliable sign: a creamy-white fungal sheet (mycelium) with a mushroom smell beneath the bark at the base of the stem or trunk, just above ground level. Peel a little bark there to check.
In the soil around affected plants you may find black or dark brown bootlace-like strands (rhizomorphs) that spread the fungus to new plants. Honey-coloured toadstools sometimes appear in autumn near affected plants, but they are not always present. Above ground, plants show dieback, poor growth and sudden death of branches or the whole plant.
How serious is it?
High for woody plants: no chemical cure, spreads underground
Honey fungus is one of the most destructive garden diseases. The RHS notes it kills the roots of woody and perennial plants and that there is no effective chemical control available to gardeners.
Its seriousness depends on the species and your planting. It spreads underground via the bootlace strands, so it can move from plant to plant and persist in old roots and stumps. Some plants are far more susceptible than others, and resistant planting is a key part of living with it.
How to fix it yourself
- Confirm it by checking for the white fungal sheet under the bark at the base and black bootlace strands in the soil, as several problems cause similar dieback.
- Remove infected plants along with as much of the root and stump as possible, since the fungus survives in dead roots and woody debris.
- Do not leave old stumps and large roots in the ground, as they are a food base from which honey fungus spreads.
- Consider a physical barrier (a deep vertical root barrier) to slow underground spread to unaffected areas, as the RHS suggests.
- Replant with species known to be more resistant to honey fungus, following RHS plant lists, rather than re-using susceptible plants.
When to call a professional
- Large trees that need felling and stump removal, which is heavy and skilled work.
- Where you are unsure of the diagnosis or want a plan to protect valuable specimens nearby.
Who to call
- An Arboricultural Association (ARB Approved) tree surgeon or arborist for felling and stump removal of affected trees.
- A garden or plant-disease specialist to confirm honey fungus and advise on resistant replanting.
Indicative cost: Tree felling and stump removal are priced by size and access; diagnosis and replanting advice cost less. Prices vary by area, severity and access, so always get a written quote.
Frequently asked questions
How do I confirm honey fungus?
The most reliable sign is a creamy-white fungal sheet, with a mushroom smell, under the bark at the base of an affected stem just above ground, plus black bootlace-like strands in the soil. Honey-coloured toadstools in autumn are a clue but are not always present.
Can honey fungus be treated or cured?
No. The RHS notes there is no effective chemical control available to gardeners. Management means removing infected plants and as much root and stump as possible, using root barriers to slow spread, and replanting with more resistant species.
What does honey fungus kill?
It attacks the roots and base of trees, shrubs and woody and perennial plants, and can kill them. Some plants are far more susceptible than others, which is why choosing resistant species is an important part of living with honey fungus in a garden.
How does honey fungus spread?
Mainly underground, through black bootlace-like strands (rhizomorphs) that grow out from infected roots and stumps to reach new plants. It also survives in dead roots and woody debris, which is why removing stumps and large roots is so important.
Sources
Editor, HomesAndHedge
Oliver leads HomesAndHedge's editorial coverage of home and garden problems. He researches and writes the plain-English explainers on pests, invasive plants, damp and mould, drainage and wildlife, drawing on guidance from bodies such as the Property Care Association, the RHS and the NHS, and is clear about when a job needs a qualified professional.
Last reviewed: 8 June 2026