Reality can get skewed when there are multiple sources of information. Books, magazines, newspapers, nurseries and, most of all, the internet and social media open lots of room for contradiction. So, how do you find the right answer to gardening questions?
Experts from Oregon State University Extension Service stepped up to bust some common gardening myths. Read on to get some research-based answers to five common misconceptions.
Myth: Lime removes moss from your lawn.
Reality: Lime does not fix the problem. Moss prefers to grow in wet, shady conditions. Lawns with moss need more sunlight, which can be obtained by trimming, pruning and thinning trees. If you like the trees how they are, you will continue to have moss and should think about shade-tolerant alternatives to grass.
Moss also grows well in infertile soils, including acidic—low pH—and nitrogen-deficient soils. Grass, like a lot of cultivated plants, prefers nitrogen-rich soils. Regular fertilizer applications—four per year, two in the fall and two in the spring—with products containing nitrogen, combined with improved sun-light from pruning trees, will result in a green, dense lawn that can out-compete moss.
—Alec Kowalewski, OSU Extension turf specialist
Myth: You should top a tree to control its height.
Reality: Trees naturally attain a certain height. Topping only temporarily delays the inevitable. The resulting sucker growth, which grows rapidly in an attempt to provide food for the compromised root system, is weakly attached. This creates an even greater hazard. Additionally, the trunk is not a limb and cannot use the tree’s architectural physiology to seal the wound caused by topping. This often leads to a slow death for the tree.
—Al Shay, horticulturist and site manager for OSU’s Oak Creek Center for Urban Horticulture
Myth: When you plant a new tree or shrub, dig the hole and add an amendment to the soil before you backfill the hole.
Reality: Although amending soil with organic matter is often a good idea, it should be done on an area-wide basis, not just in a planting hole for an individual plant. Adding an organic amendment to the soil only in the planting hole tends to reduce plant growth. This happens because roots may stay within the amended soil and not grow into the native soil, creating a root-bound plant within the amended soil. If the organic amendment is not completely decomposed, it may require nitrogen for further decomposition, which competes with plant roots for minerals—resulting in reduced growth.
In the case of large shrubs or trees, decomposition of the amendment causes the plant to settle and the root collar to sink below the soil.
—Neil Bell, OSU Extension horticulturist, retired
Myth: Watering on hot, sunny days burns the plants because the water droplets magnify the sun’s rays.
Reality: It rains during the summer all around the world, and plants are just fine. More of an issue is that irrigation water evaporates and is not as effective on those hot days.
—Brooke Edmunds, OSU Extension horticulturist
For additional information, call the OSU Extension master gardeners in your area or submit a question to Ask Extension (extension.oregonstate.edu/ask-extension), an online question-and-answer service.