Ornamental crabapples are among the most notorious producers of
these unwanted stems, but many other trees and shrubs can be
afflicted, including contorted filbert, peach, apple and dogwoods.
While there are a few landscape plants that are supposed to have
very upright habits, in most plants, this upright growth results in
a weak architecture, in addition to causing overcrowding.
Limbs with narrow branch angles are more prone to internal decay and
breakage during storms.
Both suckers and watersprouts can and should be removed any time
they occur, and it is often easier to see their architecture during
the dormant season. The earlier these vigorous shoots are
removed, the better, so don't feel you must wait until winter.
The succulent growth put on by suckers and watersprouts is often
susceptible to attack by fungal pathogens, as well as sap-sucking
insects, such as aphids. Keeping after these nuisance stems
can be annoying, but better now than after several years of wood
being laid down!
Suckers should be removed at or just below the soil line using
sharp pruning shears. Watersprouts should be pruned back to
their point of origin, avoiding injury to the remaining branch but
also being careful to not leave a stub. If removed when they
are very young, watersprouts can often be rubbed off with your
gloved thumb, making summer a good time to say, "So long, suckers!"