Disease
Honey fungus
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Watch for | Watch for in January | Watch for in February | Watch for in March | Watch for in April | Watch for in May | Watch for in June | Watch for in July | Watch for in August | Watch for in September | Watch for in October | Watch for in November | Watch for in December |
What it is
Honey fungus is a group of related fungi that attack the roots and stem bases of woody plants. It is one of the most common causes of shrubs and trees dying in British gardens, but it is also widespread in healthy woodland, so finding its toadstools does not automatically mean disaster.
Symptoms
Affected plants may die suddenly in a dry summer, or decline over several years with small, pale leaves, poor flowering, early autumn colour and branch dieback. The reliable test is to peel back bark at the base of the trunk or on main roots: a creamy-white, papery sheet of fungus with a mushroomy smell confirms it. Dark brown or black strands like bootlaces may run through the soil, and clumps of honey-coloured toadstools often appear in autumn.
Cause
The fungus spreads underground through those bootlace strands, which can grow outwards from an infected stump or root and attach to nearby healthy roots. Old stumps of felled trees are a common source. Plants stressed by drought, waterlogging or root damage are most vulnerable. Spores from the toadstools play only a minor part in spread.
Control
No treatment will save a badly infected plant. Remove it along with the stump and as many roots as you can, ideally having a stump grinder take out the stump. Bin or burn the material. A vertical barrier of heavy-duty plastic sheet buried to around 45 cm deep, and protruding slightly above ground, can stop the strands reaching nearby plants. There are no chemical controls available to home gardeners.
Prevention
Keep woody plants healthy with sensible watering in drought and a good mulch. After removing an infected plant, avoid replanting the same spot with highly susceptible species; plants such as box, yew, beech and many bamboos are generally considered more resistant. Remove old stumps when you clear a site.
Plants often affected
Could it be something else?
These problems share some of the same symptoms. Compare them, or run the symptom checker with these signs ticked.
Months to keep an eye out: January, February, March, April, May, June, July, August, September, October, November and December.
Sources
Identification and life-cycle details were checked against the references below. Text and advice are our own. See our editorial policy.