White and pink crabapple tree blossoms in spring are a welcome relief
to winter's gray days. But with fewer people making crabapple jelly,
many people want crabapple trees solely for their blooms and find the
prolific crabapple fruit to be a real nuisance.
In the long run, the easiest way to enjoy the flowers but avoid the
fruit is to plant one of the flowering crab cultivars that produce no
On existing trees, you can prevent fruit from forming with the use of
plant hormones. Plant hormones, natural or synthetic, are not
pesticides, so they don't kill anything except the maturing ovaries of
the crab apple tree, but you have to be on the ball to apply the right
amount of plant hormone at the right time.
One synthetic plant hormone, called naphthalene acetic acid or NAA
causes young fruit to abort while doing no harm to the tree or
surrounding plants or insects. Follow the concentration recommendations
on the label. You also have the choice of using ethephon, a plant
growth regulator contained in products sold under such trade names as
Florel. It is a compound that readily decomposes to produce the natural
plant hormone, ethylene, which interferes with plant growth processes.
Whichever product you use, it's very important to follow the label
directions and spray trees within 10 days after they begin to bloom. If
you apply the wrong concentration, or do it at the wrong time, nothing
will happen. Timing is everything!
Source: Cheryl Moore-Gough, MSU Extension Horticulturist
from the Grower