QUESTION: Even though we have had an unseasonably wet summer, we are still wondering how to tell when we need to turn the sprinklers on our lawn. Is there a "tried and true" rule to follow?
ANSWER: To determine when your lawn needs water, check it with a probe or trowel. Dry soil will resist attempts to penetrate it and will not hold together in a ball if you squeeze it. When you do water, make sure you leave the sprinklers on long enough to moisten the soil to a depth of six inches or so, to encourage deeper root development. Deeper roots mean healthier plants and improved drought resistance. Remember that landscape trees and shrubs which have roots extending into the lawn can quickly deplete available moisture. These areas will need to be watered more frequently.
QUESTION: We recently saw an advertisement for tree fertilizer stakes in a garden magazine. Should we use them around all of our landscape trees?
ANSWER: Most trees and shrubs benefit from an application of fertilizer each year. This application should be in a liquid or granular form, applied to moist soil and watered in. Tree spikes are popular for their ease of use, but this high concentration of fertilizer may burn and kill roots. If the trees are in the lawn, they are usually receiving adequate fertilizer when the lawn is fertilized. Fertilizer to trees and shrubs should not be applied after mid-July, as this will stimulate growth and not allow the plant to acclimate properly for winter. Winter injury may result. Once trees have gone into dormancy in the fall, it is safe to make a late-season application to the lawn.
QUESTION: Why do we have so many slugs? One would think that after years of aggressively trying to eradicate them, we would begin to see a decrease in numbers.
ANSWER: Apparently someone actually took the time to survey slug populations and reported that there are more than 70,000 slugs per acre in states that receive heavy rainfall, such as Oregon and Washington.
These population numbers do not seem unreasonable when you consider that slugs are hermaphrodites, meaning that each slimy mollusk has both male and female reproductive systems. Offspring are produced by cross fertilization or mating. And remember that slugs can live anywhere from 12 months to two years and are sexually mature at three months!
Rocks, boards and tall grass all provide shelter for slugs. Eliminating these sites in addition to the use of slug baits like Sluggo and Escargot will help to reduce slug populations.
EDITOR'S NOTE: For answers to local gardening questions, contact Master Gardener Rachel Gana at 642-8723 or e-mail her at: firstname.lastname@example.org.