Margaret Lauterbach

Margaret Lauterbach: Late summer planting requires extra care

This time of year, you can usually find some great bargains on perennials, shrubs and even trees.

Plant them as soon as you can, in the right spot for sun exposure, drainage and water. If your plant came directly from a greenhouse, don’t plant it out in full sun before gradually acclimating it to that exposure. Some folks prefer to leave their plant in the container, and move the container outside, bringing it in at night for several days. That works too, but I think the sooner you get a tree or shrub in the ground, it will be better prepared for winter, growing roots into your soil.

Cover a plant with a large pot, light cloth or even a box if it wilts in direct sun, then remove that cover at night. Replace it the following morning. You may have to cover and uncover for several days until the plant has adjusted to exposure to wind and hot sun. Be sure to water it, but don’t drown it. Let the soil dry out before watering again. You don’t have to go through this hardening off process in early spring when you’re planting out bare root trees, because without leaves, they’re not transpiring much moisture or catching much sun.

Preparing new or established trees or shrubs for winter requires some extra steps. Since roots are not as hardy as the above-ground parts, pay special attention to the root area of newly-planted trees and shrubs. It’s best if you can cover the root zone with a good thick mulch of last year’s shredded leaves or old pea vines (NEON has them in bales), or grass clippings or straw that you know has not been sprayed with persistent herbicide. Do not rake up needles from evergreens for that use. I know they sell bales of evergreen needles in the southeastern part of the country, but there the trees are not subjected to temperatures as cold as we experience.

Don’t pull the mulch up tightly to the trunk, lest you give bark nibblers cover or create an environment that would favor rotting of the tree’s trunk-root area (the crown).

If you live in a part of the valley where rabbits are common, it’s best if you wrap the trunk with a tree guard each fall for the tree’s first four or five years, at least. Rabbits, voles or mice can girdle a tree trunk, destroying the tree’s circulatory system, killing it. Trunk wraps also protect the trunk from winter sun that heats bark. When night falls, cold arrives too quickly for the warm bark to adjust, leaving unprotected bark vulnerable to damage. Some folks paint trunks, even of older, established trees, with water-based whitish paints to guard against sunburn on trunks bare of leaf cover.

If you’re planting your new tree or shrub in a container, that requires extra care prior to winter. If temperatures fall to zero degrees, for instance, the woody plant’s roots feel much colder, even down to minus 20 degrees F. The reason is that containerized plants don’t have the ameliorating effect of surrounding earth. Even in our warmer winters, container plants should be covered or wheeled into sheds or garage for protection against cold.

Predictions are for a powerful El Niño this winter, and for this area that usually means a dry mild winter. That will exacerbate drought conditions for the area, but driving conditions should be good. Prior to the onset of winter, when we disconnect hoses, homeowners should supply abundant water to needled or broadleaved trees and shrubs. They do transpire (plant version of human perspire) water through the winter, especially on warm days, and if we have little precipitation, it could damage or kill shrubs and trees.

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