Honey Fungus

Honey Fungus is a major cause for tree removal and subsequent removal/ grinding of stumps. We have therefore produced a short document on what to look for and the best ways to get rid of the disease if you find yourself in the unfortunate position to have it within your garden or area of management.

General facts
  • The official name for Honey Fungus is Armillaria.
  • There is seven species of Armillaria.
  • Spreads underground in the soil up to 1m per year.
  • Affect most plants and trees.
  • Most destructive plant disease in the UK.
Most commonly affected species of Honey Fungus are:
  • Acer
  • Buddleja
  • Choisya
  • Cotoneaster
  • Cupressus
  • Eucalyptus
  • Fatsia
  • Fraxinus
  • Hydrangea
  • Laburnum
  • Magnolia
  • Prunus
  • Phracantha
  • Rosa
  • Rhododendron
  • Robinia
  • Salix
  • Viburnum
  • Wisteria
Please note this list is not inclusive of all species susceptible to Honey Fungus.

Diagnosis/ Symptoms (above ground)
  • In autumn you are likely to see the dreaded honey coloured slim toadstools. If you wish to double-check this you can take a piece, put it in a plastic bag and then tie it up. After an hour if you open it and smell inside, you will smell a honey scent.
  • Please also remember that just because the toadstools are not present it doesn’t mean honey fungus isn’t present.
  • Part of the plant may die, especially in the upper regions of the tree or plant
  • Cracking and bleeding of bark at the base of the trunk
  • Failure to flower or bloom.
Controlling
Unfortunately there is no chemical or alternative for treating Honey Fungus (at the time of writing). The quickest and most effective method is to excavate and destroy the tree and stump.

Please note that by cutting down the tree you are not removing the disease due to the fact it is stored within the roots. You will need to remove the tree and have the stump removed and grinded.

If possible try to limit the disease spreading by installing a physical barrier around the tree. This needs to be at least 45cm deep. Pond lining material (Butyl) is ideal for this purpose. The sheet should stick out of the ground by 3cm.

Replanting
Once you have removed and destroyed the diseased tree or plant you may wish to consider replanting. Some species are less susceptible to Honey Fungas than others, here is a list of these species (trees only):-
  • Alnus
  • Azara
  • Buxus
  • Calocedrus
  • Caragana
  • Carya
  • Catalpa
  • Celtis
  • Cordyline
  • Cryptomeria
  • Cydonia
  • Davidia
  • Eriobotrya
  • Exochorda
  • Ficus
  • Frangula
  • Genista
  • Ginkgo
  • Gleditsia
  • Hoheria
  • Koelreuteria
  • Lagerstroemia
  • Larix
  • Morus
  • Nothofgus
  • Nyssa
  • Olea
  • Parrotia
  • Laulownia
  • Platanus
  • Pseudotsuga
  • Ptelea
  • Pterocarya
  • Rhamnus
  • Sciadopitys
  • Stewartia
  • Styrax
  • Taxodium
  • Wollemia
  • Zelkova

If you think you may have honey fungus present on your tree or plant we are happy to take a look and help devise a plan to tackle it. Contact us here or call us on 01473 487799. If you require just a stump grinding then take a look at our page here.

All images courtesy of the Royal Horticultural Society (rhs.org.uk)