Take Advantage of Fall Sales
Many garden centers and nurseries have fall sales to reduce their inventory. What doesn’t sell, they have to spend money protecting in winter or suffer losses.
These sales are timed right for you, too, because early fall is a great time for planting trees, shrubs and perennials, as the plants have time to establish roots in their new soils before winter sets in.
Plants produce new roots faster when their tops are going dormant. In preparation for winter, most woody plants stop growing leaves and new shoots starting in mid-August when daylight hours grow shorter and evenings become cooler. Thus, all of the sugars being produced by the foliage are directed toward growing new roots. New roots this fall means more top growth next spring.
Container-grown plants you buy now have been growing in that container all summer. Therefore, it is likely that the outer edge of the root balls are encircled by roots, a good indication that the plants are root-bound. If you transplant such plants without disturbing the roots, it is unlikely that they will survive the winter because new roots cannot break through the mat into the surrounding soil.
When removing plants from their containers, examine the root balls carefully. If the roots have filled the container, pull them loose or slash them with a sharp knife. I prefer slashing the outer edge of the root ball from the top to the bottom approximately one inch deep at three- or four-inch intervals. By slashing the outer roots, you will be forcing the fine roots to branch and form new roots in the new soil.
An alternative method is to crush the root ball until you see the roots loosen, and use your fingers to pull the loosened roots away from the ball. This method requires more time but achieves similar results.
Never dig the transplant hole any deeper than the depth of the root ball. Ninety percent of the roots of trees and shrubs are in the upper six inches of soil. Plant with 10 percent of the root ball above grade. Back-fill with a mixture of one-third by volume compost blended with two-thirds by volume existing soil.
The compost will provide not only the essential nutrients for good root growth but also a transition zone for roots that have been growing in a soilless mixture. If you are transplanting azaleas, blueberries and related species, blend one to two tablespoons of gypsum into the soil before backfilling. Acid soils are nearly always deficient in calcium, which is essential for good root growth.
Ask Dr. Gouin your questions at [email protected]. Please include your name and address.