Photo credit: Baltimore Sun/Kenneth Lam
Day Two of myth busting for gardeners, courtesy of the U.S. National Arboretum's Scott Aker.
Plant the largest size tree stock you can. That way, you will have a big tree, faster.
"A big tree in the beginning does not mean a bigger tree in the end," said Aker. A large caliper tree will loose 70 percent of its root mass in the transplanting and will spend much of the rest of its life in shock, Aker explained.
He recommends planting a tree that has a caliper of 1 to 2 inches. The tree will become established quickly and grow quickly.
When planting, handle plants gently and don't disturb their roots.
Plants look roots every year and they replace them," said Aker. "They need to do that to have good function."
Aker recommends roughing up the soil wall of a potted plant with a garden knife or the edge of a trowel to prevent root girdling.
Ailing trees and shrubs should be fertilized to "perk them up."
"Here we go again," Aker said, "personalizing our plants."
In fact, if you fertilize an ailing tree, shrub or plant, you may actually burn the roots.
And, he said, "trees make up their own mind whether to live or die and their death probably started five years ago. Decline starts slow and it is irreversible."
Aker recommends "air spading" for trees. Compressed air is shot into the root system to open it up for oxygen, water and nutrient flow. This can often give trees a boost.
Deep fertilization is good for trees.
Tree roots are not a mirror of the treetop, Aker said, dispelling one more myth. They go out, not down. In fact, they form a kind of "pancake" only 12 to 18 inches deep. "Because that's where the life and the oxygen is.
Aker's advice? "Don't fertilize at all. Use organic mulch. If you must fertilize, use a slow release fertilizer on the surface in the fall.
Fertilize your grass in the spring.
Fertilizing in the spring can actually set up your grass for disease. It is better, Aker said, to fertilize in the fall when root growth is more active.
He also suggests that you mow 5 inches high (if you can find a mower that will let you set it that high!) and let the clippings lay on the lawn.
Mowing close to the ground, he said, does not slow lawn growth (that is, you won't be mowing less often), it encourages weed growth because they are suddenly getting the sunshine they want and "besides, mowing is very stressful for turf."
All plants do best with lots of watering.
"Use water sparingly and judiciously," said Aker, who is not a fan of all the watering going on in gardens. "Don't over react in times of drought."
Aker believes that irrigation systems, that automatically water 20 minutes a day, are killing more lawns and gardens than they are saving.
Every two to three weeks, he said, gardeners should water 6 to 8 inches deep. This takes time and patience. And it isn't accomplished by dampening the top of the garden every evening for a few minutes.
If you are concerned about runoff, water for 20 minutes, and then turn off the hose for 15 minutes. Continue this process until, when you check the soil, it is watered to the 6 to 8-inch depth he recommends.
More mulch is better.
Mulch to a depth of only 1 or two inches under shrubs and trees, but maintain it, Aker said.
And mulch may actually be bad for your perennial beds. The decomposition of the mulch draws nutrients out of the soils and if it gets in the crown of the perennial, which is likely to happen during the spring mulching season, it can harbor moisture and encourage disease.