Purdue Ag News Roundup
Purdue Ag News Roundup
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June 19, 1998
Tolerate weeds in lawn until fall, expert advisesWEST LAFAYETTE, Ind. -- Midsummer isn't the best time to try to control broadleaf weeds in lawns, says Purdue University turfgrass extension specialist Zac Reicher.Spraying broadleaf weeds at this time of year risks causing damage to landscape ornamentals, he said. "Many people think that it takes direct application to ornamentals to cause damage, but spray drift in mist or vapor can also cause damage," Reicher said. "The best way to avoid damage is to apply in October when these herbicides are most effective and when ornamentals are not susceptible to damage." In midsummer, the broadleaf weeds are pulling nutrients from the ground and sending them upward through the plant to the leaves. As fall nears, the nutrient flow reverses, as the plants begin sending nutrients from the leaves to the roots for the winter. Herbicides applied in late September or in October have a better chance of killing the entire plant. According to Reicher, if homeowners are absolutely determined to apply herbicides in midsummer, they should take these precautions:
CONTACT: Reicher, (765) 494-9737; zreicher@dept.agry.purdue.edu; http://www.agry.purdue.edu/agronomy/turf/zjr-bio.htm
Trees may require nip and tuck after stormsWEST LAFAYETTE, Ind. -- Homeowners assessing tree damage caused by recent storms will want to make a few important decisions soon, according to Purdue University consumer horticulturist B. Rosie Lerner."Small trees with minor damage can probably be taken care of by the homeowner," Lerner said, "but large, mature trees will likely need the help of a professional tree service." It can be hard to decide whether to remove trees with severe damage, the horticulturist said. Homeowners often are reluctant to cut down a tree, either because of sentimental attachment or because the tree provides shade or screening that won't quickly be replaced. But Lerner stressed that safety should be the first priority. "Assess whether the tree itself or some of its branches are in danger of falling -- now or in the near future," she said. "If the tree isn't an immediate danger, you may be able to plant a new tree nearby and wait for it to grow a bit before removing the old tree. Just because a trunk is split doesn't necessarily mean the tree will die soon." Large, split trunks or branches that haven't broken off the tree can be braced and possibly saved by an arborist, Lerner said. If limbs have fallen completely off the tree, there is nothing that can be done to save them. In either case, she said, the wounded area in the tree will always be a weak spot that's susceptible to disease, rotting and insects. If trees just have a few damaged limbs, Lerner said, it's relatively easy to remove small, lower branches with loppers or a pruning saw. "Use sharp pruning tools appropriate to the size of the job to ensure a clean, smooth cut," she said. She recommends using hand shears on branches up to one-quarter inch in diameter, loppers on branches up to one and a half inch in diameter, and a pruning saw on larger branches. "While you're trimming broken branches, look for branches that have already broken free and may have left a jagged stump on the trunk," Lerner said. "Make a cleaner cut on those branches to help the tree wound seal more easily." For larger limbs, or those too far up for the owner to reach, she suggests hiring an arborist or other professional service. They'll have the appropriate tools and equipment to safely bring down large or high limbs so that tree, home or other nearby objects won't be damaged. "In general, pruning sealants or paint are no longer recommended for treating pruning wounds," Lerner said. "There's some controversy regarding these products, but generally they've not been shown to be helpful. Some scientists believe the sealant actually may interfere with the tree's ability to form a protective callous over the wound." For more information on pruning, contact a Purdue Cooperative Extension Service office and ask for Extension publication HO-4, "Pruning Ornamental Trees and Shrubs." For a professional arborist, look in the yellow pages of your local telephone directory under "tree service." Lerner said it's wise to get estimates from several firms and references from other people who have used a service before signing a contract. CONTACT: Lerner, (765) 494-1311; e-mail, brl@hort.purdue.edu
Compiled by Chris Sigurdson, (765) 494-8415; E-mail, sig@ecn.purdue.edu
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