Chemical to Cause Fruit Drop in Ornamental Plum

Q. I have an ornamental flowering plum that produces fruit. I want to spray it to stop the fruit production and the messiness it brings. Last year I had a commercial applicator apply it, but I think I want to save some money and do it myself this year.

This is ornamental (flowering) plum fruit. The fruit is harvested by many to make a very tart (lots of sugar) jam or jelly. Commercially it is available as a fruit tree called 'Sprite' and 'Delight'.

A. Mark your calendar because yours will flower within the same week, plus or minus, every year. You’ll have to spray the tree with a chemical every year to get the fruit to drop when it’s still small and prevent the messiness later. To get it to work, spray the entire canopy of the tree when as many of the flowers are open as possible.

Applying Olive Stop

            You will find it under several different similar trade names like, “Olive Stop”, “Fruit Eliminator”, “Fruit Be Gone”, or some similar name. What is important is the active ingredient listed on the front label in small letters. The most common active ingredient is Florel, but you might also find it listed as NAA, Fruitone, etc.

How to Use it

            This concentrated spray is diluted with water and first sprayed when the flowers on the tree are fully open 20 to 30%. For best results it is sprayed again at 80% of full bloom a couple weeks later. Commercial applicators spray the tree a single time when it’s close to full bloom. It’s a good idea to include a wetting agent or surfactant before spraying to improve the sprays coverage and penetration.

            It’s important that the flowers are open and sprayed to the point where the inside is wet, and the flower starts dripping when you’re finished. The canopy of the tree is dripping with the spray when you’re done. This is called “to the point of runoff”. Spraying the open flowers above their reach is the usual problem for most homeowners because they don’t have a good way of spraying all the flowers.

Ornamental Flowering Plum

            The ornamental flowering plum is an actual fruit tree. Nothing wrong with the fruit. It’s naturally “puckery”. Many people make jam and jelly with it when the fruit is not sprayed. I would not recommend making jam or jelly with it if it’s been sprayed. Add as much sugar to it as your taste permits.