Cold Spring, Slow Start for Plants

Are your lawn and landscape off to a slow start this spring? If so, you haven’t lost your green thumb. Weather conditions this spring have not been conducive to rapid spring growth.

Warm season plants, including permanent lawns, annual bedding plants, perennials, shrubs and trees, require relatively high temperatures to grow rapidly. In general, soil temperatures must stabilize above 70 degrees F., and daytime temperatures above 80 degrees are needed.

Night temperatures, to a great degree, influence the soil temperature and hence, the growth rate and development of warm season plants. Even though we have experienced some warm, sunny days this spring, nights have been consistently cooler than normal. During March, April and early May most nights have been in the 40 to 60 degree range.

Even though we are off to a slow start, there is still time for a successful gardening season. Lawns have begun more rapid growth and are beginning to fill in spring dead spots. Tomatoes are finally beginning to set fruit and flowering annuals and perennials are enjoying a flush of bloom.

The results of early spring maintenance, although delayed this year, will nevertheless pay off later. Early applications of fertilizer might be an exception. Since little growth occurred, some of these nutrients, particularly nitrogen and potassium were probably wasted unless slow release or controlled release forms were used.

A spring such as we are experiencing emphasizes the importance of the timing of fertilizer applications. Even when normal spring weather is expected, late February and early March fertilizer applications are generally too early.

Pest Alert

The recent dry weather has resulted in increased infestations of lacebugs on azaleas and spidermites on many species of shrubs and flowering plants. Lacebugs are found feeding on the underside of azalea leaves. They pierce and suck sap, resulting in foliage that takes on a stippled or whitish cast. Lacebugs are easily controlled with spray applications of insecticidal soap, acephate (Orthene), Diazinon, Sevin or malathion. Di-Syston granules can also be applied to the soil beneath plants for systemic control of these pests.

Spider mites feed on a wide range of ornamental plants. Until normal rainfall patterns return, plants should be inspected weekly and infested plants should be treated. Use a hand lense and examine the undersides of leaves. Look carefully because mites are tiny, measuring only one - fiftieth of an inch in length. Products for control include insecticidal soap, Kelthane and Di-Syston granules.

There are currently several species of ornamentals that are being heavily infested with spider mites. Japanese hollies and junipers are especially vulnerable. Daylily growers take note: A heavy infestation of the two-spotted spider mite was found on a large planting last week. Inspect your daylily plantings immediately and apply control measures, if needed.

Question of the Week: The leaves on my hickory trees have many round objects on them. What are they and will they harm my trees?

Answer: These are galls caused by the pecan/hickory phylloxera. These small insects sometimes infest new leaves as they emerge from the buds during spring. The adults deposit eggs and stimulate the leaves to develop galls. The young phylloxera then develop within.

This is not a chronic condition and is not a serious threat to the long term health of your trees. Expect some of the most heavily infested leaves to fall earlier than normal. Treatment of this disorder on hickories is generally not recommended.