Hi! I am trying to figure out what is wrong with a Hawthorn (Crataegus) tree. It is part of a long row of Hawthorns and is one of a few that appear to be diseased. The tree's branches and twigs are covered in black, bumpy, woody growths. The trees with these growths appear to be in poorer health than the surrounding trees, (dead branches, late leafing). Does anyone know what the problem is, and if you do, is there a treatment and should I be concerned about it spreading to the other Hawthorns? Any thoughts would be welcome. Thank you!
