Twenty years ago, we planted an acorn in the garden, and it has now grown into a mighty oak tree. But quite a lot of the acorns are horribly mutated. Why is this, is it common, or indicative of some disease in the tree? The tree itself appears healthy in all other respects, and it does produce normal acorns as well, as shown in the image.
Wow, that is magnificent!
I have a tiny oak growing in garden, probably acorn was dropped bird. It is now about a meter high, but unfortunately it has powdery mildew, and I am at a loss what to do with it.
Alas, Bob, I have no answer for you - maybe Google for an oak specialist? Odd that some are okay and others not...
Ours suffered from a bit of mildew at first, but it got over it, and now looks very healthy apart from some funny acorns. We have a load of squirels leaping about in it all the time, and they eat all the normal acorns, but seem to leave the funny ones. Wood pigeons also like sitting on the branches and the squirrels never bother them.
The acorns are mutated because knopper gall wasps have laid their eggs inside them. Apparently, this does not do the tree much good, so the affected acorns should be clipped off. But our tree is now too tall from that, so it will just have to deal with them itself. They say that this type of wasp did not appear in the UK until the 1960s.