beautiful old apple tree is covered in lichen. I like the look of
it, but I'm worried it's damaging the tree. Should I do something
doesn't do the tree any harm. It's actually a good sign, as lichen
needs clean air to survive. In parts of the world where pollution
is bad, lichens are becoming rare.
Lichens are two organisms
living in symbiosis - a fungus shelters an alga which provides food
for the fungus. Vigorously growing trees shed bark regularly, which
tends to limit lichen growth, so it's also a sign your apple tree
isn't growing very strongly. I suggest you feed the tree to encourage
more growth and, if you do wish to remove some of the lichen, simply
try brushing it off. If you want to deal to it on a larger scale,
spray with lime sulphur in winter when the tree is dormant, or paint
the spray solution on to the lichen.
Gardener, Issue 145, 2004, Page 27
Reproduced with permission from the former Weekend Gardener magazine. The views expressed here are not necessarily those of the RNZIH.