Mulberry with 5 trunks
I have a mulberry in southwest Colorado which is about 10 years old and has 5 trunks each about 4" to 6" in diameter. It only fruits every two or three years. I read to put 1 lb of 10-10-10 for every inch of trunk. Is this too much? Have not seen other mulberry trees with multiple trunks --- should I cut them off, or will it kill the tree at this stage? Also there are section of the bark that have split with bare trunk...what causes this?
Certified GKH Gardening Expert
This is a common occurrence with mulberries. There will be no need to prune any trunks, unless you just can't get to the tree to harvest anymore. As far as fertilizing goes... The best thing that you can do here is to guess the approximate diameter of all of the trunks if you were to squish them all together. In your case, I would treat it as, roughly, 12 inches or so.
It will be better to underfertilize then over. Go a little light on it this year, and spread it away from the trunk, since the feeder roots are further from the tree.