Originally created 04/10/98

Trimming young azaleas after they bloom can strenghten plants



In spite of all the crazy weather we've had this winter and spring, the azaleas have been beautiful. The cold weather we had in early March killed a few buds, but it also delayed most of the blooms so we have had a more magnificent display this week.Remember not to neglect your azaleas after they finish blooming. The best time to prune or cut back your plants is right after the flowers fall off. There are two important reasons to prune at this time. One, it allows the new growth to mature so that flower buds will form to flower next spring, Second, it allows new tissue to mature and harden off, helping prevent freeze damage in the fall or winter.

I have seen plants pruned late in the summer and the new growth gets damaged by an early fall frost. The result is usually mortality for the new shoots, but it doesn't show up until now. If you see dead shoots on azaleas, look for split bark on the lower branches or stems. When the bark is completely split, death will usually occur by spring. If the bark is partially split, you may not see dead branches until the following fall when fungus or other organisms that enter the damaged tissue have destroyed the xylem. Dead shoots can be cut below the wound, and the plant will continue to live and grow.

Pruning in the late summer or early fall can also result in removal of existing flower buds. Extensive late-summer pruning that stimulates new growth can delay plant maturity so that flower buds are not set.Plants that are cut back extensively in the spring may require another light pruning in early summer to increase branching or to thin out excessive branches. A light pruning in early summer should not reduce bud count.You also need to be on the lookout for azalea lace bugs. They are the main pest of azaleas. Adult lace bugs are flattened and rectangular in shape and 1/8 to 1/4 inch long. The area behind the head and the wing covers form a broadened, lace-like covering over the body of the insect. The wings of most lace bugs are light amber to transparent and have dark brown to black spots. Lace bugs feed on the underside of leaves and extract the contents of the upper layer of cells. This causes the azalea leaves to appear bleached or mottled.

Controlling lace bugs in March and April, while they are young, is the key. The bugs spend the winter as an egg inside your azalea's leaves.When temperatures begin to warm in the spring, the eggs begin to hatch.The newly emerged nymphs then begin to feed. The nymphs are flat and oval in shape with spines projecting from their bodies in all directions.Your goal should be to get rid of these nymphs before they mature and have time to lay eggs. If you don't, they will have laid eggs, and you will have to spray several times. Lace bugs can produce four generations from spring to fall. If you kill the first generation, you may not have to spray again.

You have several options when it comes to sprays. Horticultural oils and insecticidal soaps are organic and work well. But they are contact sprays, and you must aim for the bugs underneath the leaves. And don't use oils in hot weather. It can burn the plants.

Good systemic insecticides to use would be Orthene and Cygon. You don't have to aim underneath the leaves, and they will last about six weeks.But remember, killing the first generation probably means you wouldn't have to spray again anyway.Many folks never spray for lace bugs and their plants suffer, with the young plants suffering the most. Older plants that have been in the landscape for several years can withstand more lace bug damage. They can tolerate some damage because they have well established root systems and are not already under stress, as newly transplanted azaleas are. But young plants may actually die because of the stress. This is one reason many homeowners keep replacing young plants year after year.

:Deer-resistant plants

Many of you live in areas where you have deer munching on your landscape plants. If this is a problem, consider planting things deer don't care to eat. But please remember that no plants are totally deer-resistant. When deer populations are high and food becomes scarce, deer are more likely to feed on ornamental plants. Deer prefer tender new foliage on newly planted ornamentals and those fertilized to produce lush new growth. During dry weather, deer are attracted to irrigated plants.Any local Extension Service office has lists of plants deer love to eat and those that are known to have a high degree of deer resistance. Many of our local garden centers also have a copy of this list.

Watermelon

For years it was thought that watermelons were bland after a heavy rain because the water was taken up by the roots and diluted the sugar content of the fruit. This need not happen any more if you can harvest within a day or two of a rain, or wait a week later, when the fruit's sugar rebounds.

Scientists have learned that the real culprit is a halt in the fruit's sugar import about four days after a heavy rain. First, roots shut down, stressed because they can't take up oxygen from water-saturated soil. Then they signal the leaves to stop photosynthesizing sugar.Meanwhile, the sugar that is in the melon starts breaking down and, without the new sugar being processed, the melon tastes bland.



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