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 fruit.
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!
