We have an apple tree which came up out of the compost, presumably from the seed of an ordinary fruit shop apple, and we left it to grow to see what happened. Last season it produced its first apples, smallish red ones and nice to eat.
Recently we discovered something strange going on with its bark on the trunk and some lower branches. Not sure when it started because we hadn't paid much attention to the tree since harvesting the apples in autumn. The internet shows us pictures of canker and fire blight (along with many diseases of the leaves and fruit) but nothing that looks like these warty things. Does anyone know what this is? Is it going to kill the tree, and is there anything we can do to treat it?
Dont know myself but somehow it looks a healthy growth of some kind,ive posted this photo on another garden forum and asked the question
If it is low down on the trunk it could be air roots ready to grow if - I have this on one of our seedling trees and also on one that was planted too high so the bark that has root hormones was above the ground.
Think it is not a disease but merely a hormone issue of the bark?
But also would like to know the real answer!
Yes burr knots,you can even cut them off a small branch bearing these burrs in winter and they will root in damp sand.
Thank you all! An article says that burr knots are common in root stocks because they've been selected to grow roots enthusiastically; it's a bit odd that this tree is making them when it's from a seed of the top part of a commercial grafted tree, not the root stock. They're not all low down on the trunk either -- they are evenly spread around the trunk and lower branches up to nearly waist height. Very glad to hear the tree isn't infected by anything horrible.