June 2010: After a period of high temperatures in the UK during May, early June saw temperatures drop along with the appearance of wet and rainy weather. These conditions will often prompt the appearance of mushrooms around the surface of my bonsai.
The mushrooms on this Privet appear every year, growing on the rotting deadwood at the base of the tree and the surrounding soil. Although the wood has been hardened with a plasticiser several times in an attempt to stop it rotting, it is pretty much impossible to stop this amount of deadwood from rotting completely.
Mushrooms are the fruit of a wide variety of naturally fungi that grow on and around trees. Fungi will have varying relationships with the tree itself; some will have a symbiotic relationship where they are beneficial to the health of tree and its root system. Others will colonise organic particles in the soil and break them down, (also known as 'rotting').
Rarely are the fungi themselves harmful to the tree, rather, as they colonise rotting wood, mushrooms seen growing from the trunk of a bonsai will often indicate rot within the wood of a trunk itself.
The mushrooms around this English Elm are the fruits of a fungus that is growing on small pieces of elm wood in the soil. Also, the bonsai started life as an airlayer and the base of the trunk is naturally rotting as is usual with large airlayers.