Pamela J. Bennett, Ohio State University Extension, Clark County.
Reports of winter injury were few this past growing season. There were numerous reports, however, of deciduous plant material blooming out of season. Sporadic late summer and fall blooms were reported on magnolia, royal paulownia, Callery pears, crabapples, rhododendrons, azaleas, and viburnums. Speculation was that summer drought conditions had induced this unusual bloom period.
There were, however, reports of plant problems due to the cold, wet, prolonged spring followed by several days of extremely warm weather. Hostas exhibited leaf scorch; 2" to 4" caliper maples were in the wilt stage; and yews were reported to have new growth turn brown and others completely died. In most cases, these plants had other variables associated with the problems, such as improper planting and mulching or being newly established; the weather, however, exacerbated the situation.
Irrigation was also an issue this past growing season. There were numerous questions regarding proper watering techniques. Thorough, deep watering was recommended. Established trees and shrubs can go longer periods without water depending upon the extent and depth of their root systems.
Young plants, either newly planted or planted within the last few years, require more water. A young tree up to 2.5" caliper requires about 5 gallons of water every 7 to 10 days to survive. Larger trees, 3 to 4" caliper, need about 10 gallons per tree every 7 to 10 days. It is quite difficult to water large, established trees; however, if they begin to show wilting, begin to change color prematurely, or if the margin of the leaves begins to turn brown (leaf scorch), apply 2" of water beneath the crown of the tree.
In addition, BYGL readers were reminded that drought-stressed plants were subject to greater risks of insect borer attacks. Most plant cells fully engorged with water, or turgid, have a defense mechanism to protect themselves from many borer pests.