Crabapple suckering

Some grafted and budded shrubs and trees develop a bad habit to sending up shoots (suckering) from its rootsystem. This creates an untidy appearance around the base of shrubs and trees. Far worse, the root suckers may compete for domination over the cultivar graft. They may rob photosynthate, water and nutrients from the grafted plant. Eventually, the grafted portion may die.

Gardeners select grafted plants for a number of reasons. The grafted cultivar may exhibit more attractive foliage (e.g. Japanese maples, European beech, or purple leaf plum) or better disease resistance (e.g. crabapples, callery pears).

Rootsystems also may have desirable features. Dwarf rootstocks reduce the size of apple trees. Hybrid tea roses are mostly grafted on a rootsystem capable of growing in most soil types. 

Sucker growth above ground may be susceptible to fire blight disease, a serious bacterial pathogen which is difficult to control. Aphids, lacebugs, leafhoppers and borers may contaminate wood with serious virus pathogens.

Don’t attempt to spray the sucker growth with a translocated contact herbicide such as Glyphosate ( Roundup™ and other trade names) or Phenoxy herbicides such as 2,4-D, dicamba and MCPP). These chemicals likely will move to the rootsystem to injure or kill the tree.