If you are tiptoeing around the sharp, spiky seedpods of liquidambar (sweet gum) trees throughout the year, now is the time to control their development.
Peering into your liquidambar tree in early spring...
look for this rather unremarkable flower:
If you see those, it's the time to spray a product containing the growth regulator, Ethephon. One such product is Monterey Lawn & Garden Products' Florel. Thoroughly sprayed onto the blooms of an ornamental tree that produces undesirable fruit, the chemical causes the blossoms to abort, stopping fruit production. In the case of the liquidambar tree, the fruit are those sharp seedpods that are the bane of barefooters everywhere.
According to Monterey, "the best time to spray Florel is when the flowering plant is in the mid to full bloom stage. The ideal time for spraying sweet gum (liquidambar) is right after the tiny balls form below the catkin. After application, these tiny balls simply dry up and fall off."
According to the product label, Florel will also control undesirable fruit on other ornamental plants such as Buckeye, Crabapple, Carob, Cottonwood, Elm, Flowering pear, Horsechestnut, Maple, Oak, Olive, Pine, Sour orange and Sycamore trees.
A few notes about applying this growth regulator:
• Read and follow all label directions.
• Timing is critical. There is a short window of opportunity to spray while the blossoms are in mid to full bloom.
• Thorough coverage is necessary. Monterey suggests it takes about 5 to 20 gallons of the Florel and water mixed together to coat the flowers of a tree, up to the point of runoff. One quart of Florel makes about 10 gallons of mix.
• The product works best when applied during daytime temperatures of 65-90 degrees.
• Use the mixed product immediately. When first combined, the mix has a very acid pH of 2.5; but that acidity decreases as the mix hydrolizes, reducing its effectiveness.
• And how do you reach those blossoms that are out of the reach of your sprayer? That's when it's time to call in the arborist with a crane.