FOR RELEASE THE WEEK OF JUNE 3, 2001:
We got a new puppy last fall, and several spotty sections of our lawn did not revive this spring. They're yellow and dead-looking and seem to be the victim of overly frequent doggy visits. (They're around her favorite tree.) If we reroute the dog to another section of the lawn, will these recover? Or do we need to do something else to help them spring back to life?
Dog blight--small, circular dead spots of grass usually surrounded by grass that is darker and faster-growing than the rest of the lawn--is very common, especially with female dogs.
"The problem stems from the concentration of salts in one spot," says Wayne Jones, University of Idaho Extension educator. If you have good drainage, you can try to leach out the salt by irrigating the dead spots more heavily. Even if you do nothing, dog-blight spots usually correct themselves in time as the salts are used.
Fortunately, most of the turfgrasses commonly grown in Idaho have rhizomes or stolons just at or under the soil surface that will fill in the dead spots as conditions improve, says Jones.
When and how should I prune my flowering quince?
Like other spring-flowering shrubs, flowering quince should be pruned after it blooms, says Danny Barney, University of Idaho Extension horticulturist. So should forsythia, spirea, mockorange, Deutzia, lilac, Viburnum lantana, bush roses, azaleas and rhododendrons, all of which will become leggy and unattractive without regular pruning.
For a compact, healthy shrub that will be loaded with blossoms next spring, sharpen your hand pruners and begin by cutting out any dead, diseased or spindly branches. Then, remove a few older branches close to the ground, taking care not to leave long stubs that will invite pests and diseases. Repeating this process for the next few years will keep your shrub young and vigorous.
Leave a few 1-year-old suckers to replace the older branches that you've pruned out, and remove any excess suckers to prevent crowding. Next, prune back 2-year-old or older leggy branches to outward-pointed buds or side branches. Be careful not to prune branches too short because that produces dense, overcrowded growth that can spoil a shrub's natural shape and increase pest and disease problems.
"Unless you are creating a hedge or topiary, try to preserve the shrub's natural, graceful shape," Barney advises. "Retain well-spaced branches to create an open canopy that allows light and air movement into the center of the shrub. Then sit back and enjoy the view for another year."
Is it true that if you mow your lawn higher, it will tolerate drought better? How high should I mow it?
In most Idaho lawns, Kentucky bluegrass is still the predominant turfgrass. According to Wayne Jones, University of Idaho Extension educator, each type of lawn has what is called a "tolerance range" for optimum performance and its height should fall within it. Because Kentucky bluegrass' tolerance range is 1 1/2 to 3 inches, that's where your mower height should be set.
"Taller turfgrass has deeper roots," Jones says. "If you mow your grass shorter than its tolerance range, its roots will shorten and it will form more aerial shoots." As a result, its ability to withstand heat and drought will be compromised and you'll need to water and fertilize more frequently. Because shorter-rooted turf stores fewer carbohydrates, its susceptibility to disease may also increase.
On the other hand, if you mow above the tolerance range, you'll notice your grass becoming limp and puffy.
"The best thing to do is to let the grass grow to the upper limit of its tolerance range when the summer heat and drought hit," says Jones. Then clip a third of it back when you mow.
[READERS: Do you have a question about your home, yard or garden? Send it to HomeWise, University of Idaho Ag Communications, Moscow, ID 83844-2332 or e-mail it to homewise@uidaho.edu. Mention of proprietary products or firms does not constitute endorsement by the University of Idaho Cooperative Extension System or imply approval to the exclusion of other suitable products or firms.]