Horticulture Hotline 01/16/17
By Bill Lamson-Scribner
The question about pruning Crepe Myrtles and other plants seem to top the list of questions for this week. The butchers are out there! The time is now for getting in your soil test, so you can amend the soil by spring time. Do you have any disease prone plants (roses, etc.) that could benefit from a little sanitation? What is the population of moles in the Lowcountry? What is the population of moles in your yard? Have you applied Neem Oil for overwintering insects and disease?
Crepe Myrtles are the most abused tree in the landscape. Since they bloom on new growth, someone “topped” them a while back and notice the flush of new growth and the prolific blooms. These heavy blooms are supported by wimpy 18 – 24 sprouts that just developed that growing season. When it rains, the bloom catches water and becomes even heavier. The bloom will hang down and eventually the wimpy new growth supporting the bloom will split off tree leaving an open wound for insects and disease.
Instead of “topping” the tree to increase blooms, a good fertility program will accomplish the same thing without ruining the beautiful natural branch structure of the tree. A soil test and program can guide you to the right fertilizer for your tree. Have you ever seen a Crepe Myrtle in the winter when the leaves are gone, and sense the tree’s embarrassment, like a dog with the cone on its head? A tree that has been “topped” is standing there naked of any foliage with these big nasty swollen knobs at the end of the branch, like huge warts. The tree that is pruned correctly is standing there naked and proud, like a nude Greek Statue.
The correct pruning for a Crepe Myrtle involves removing dead limbs and crossing limbs. Any limbs growing toward the middle of the tree are good candidates for removal. If a limb is growing to the outside of the tree let it be. Opening up the center some for sunlight penetration and air movement is always a good idea to help prevent disease. Sometimes Crepe Myrtles, being a multi-trunk tree, can have too many canes growing from the ground, and one of these needs to be removed. Removing these canes is best done while the tree is very young; however, you can prune these canes out once the tree is older.
There is a very rare occasion that a landscape designer orders that a tree should be topped. Under certain circumstances usually involving safety concerns or visibility concerns a designer will recommend keeping the tree at a certain height. When I worked on Hilton Head, we had a safety situation by a guard gate that required us to “top” the Crepe Myrtles; however, we did not “top” the other Crepe Myrtles in the project. Some businesses want their sign to be seen, and Citadel Mall is practicing pollarding, a type of severe pruning that the Crepe Myrtle can tolerate.
Now days, Crepe Myrtles are available in all different sizes from 3 feet to 30 feet, so planting the right one to fit the scale of your landscape is crucial. Much of this “topping” can be avoided with the proper plant selection and proper fertility. Whoever is planting the tree (or any plant) should look at its mature height and spread. Then plant the right plant for the space.
If you live in Mt. Pleasant, learn the local ordinances because they have laws about the proper pruning of Crepe Myrtles.
After you prune your Crepe Myrtle properly, now is the perfect time to add Cotton Burr Compost as a mulch, SeaHume as a biostimulant and minor nutrient treasure chest, and a tree and shrub drench for insect protection.
Spring is coming. Preemerge?