Gardeners stay busy with April maintenance

Taking care of the yard keeps gardeners busy in April. Here are some of their questions, as they appeared in my voice mail.

Q. I have discovered wood borers in my rhododendrons. What can I do to save them? — V.G., Lynchburg
A. Rhododendrons across our area suddenly developed dead branches over the past month as a result of injury caused by rhododendron borer. The larvae of this pest feed under the bark of rhododendrons, slowly cutting off the flow of water upward from the roots. The chemical option for controlling this pest is to spray the rhododendron trunks and branches with permethrin in late June. A non-toxic option is to switch to growing azaleas and camellias instead of rhododendrons. They are not bothered by rhododendron borer.

Q. I have used Scotts winterizer, Scotts fertilizer and weed killer. I have used lime and I have used everything on my lawn, and I have some lighter green patches and I have some moles. I wonder if grub worms eat off the roots and leave lighter green spots.
— E.S., Lynchburg
A. Patches of light green grass in an otherwise dark green lawn are not caused by grubs at this time of year. Among the more likely causes are an infestation of annual bluegrass or other yellowish weeds, an overdose of fertilizer or weed killer or compacted soil. Riding lawnmowers contribute to soil compaction, which leads to yellowish patches of grass deficient in iron.

Q. We have a customer who wants some woody ornamentals such as crape myrtle pruned back pretty hard. What I’m wondering is if we are going to mess things up by pruning them now after the weather has warmed up and things are starting to grow. We usually do our pruning in February. — B.S., Altavista
A. The plants you would normally prune in February can also be pruned in March, April and May. Pruning late may delay the flowering season by a few weeks for summer-bloomers like crape myrtle, but it is no big problem.

Q. I want to grow two new annual flowers in my yard this summer. What flowers do deer not eat?
— J.M., Lynchburg
A. Two worth trying are celosia (cockscomb) and vinca (Madagascar periwinkle). I have never heard of deer eating either one. Many kinds of deer-resistant plants will be sold at the Hill City Master Gardener Association’s Festival of Gardening in Miller Park on May 1. Plant sales start at 8:30 a.m.

Q. I am calling concerning my camellias. I have them on each side of my steps as you come up and they are real brown. I was just wondering if you can cut them back now.
— N.W., Forest
A. Spring is the time to prune all camellias. This includes sasanqua and other fall-bloomers plus the more popular japonica varieties.

Davis is an Extension Agent for the Virginia Cooperative Extension. He can be reached by calling 455-3740.