Putting the garden and yard to bed

Molly Nemec

Chisago County
Master Gardener

Summer may be over, but there’s still plenty to do. Spending crisp, sunny days in the yard is a worthy way to get exercise and vitamin D before the dark days of winter.

One chore is to water newly planted trees. To increase winter survival rates, trees need an inch of water per week until the ground freezes. Measure each rainfall, and when necessary, water young trees liberally.

Saturate the soil with a slow-running hose near the drip line, the outermost circumference of the tree canopy. Water long enough to soak the entire root zone.

Evergreen trees are susceptible to winter burn. Sun and cold wind cause pine, spruce, arborvitae and yews to transpire, losing water through the needles. Because the ground is frozen, the trees are unable to replenish moisture through the roots.

To lessen the damage, make sure evergreens are well-watered when winter starts. Continue watering into December if the soil is not frozen.

Sun scald affects young, thin-barked  trees such as maple, honey locust, linden, plum, apple, mountain ash and crab apple. Late winter sun stimulates the cambial tissue to become active. Then, when temperatures dip at night, the active tissue is damaged. The result is a splitting wound that can decay, leading to a weak trunk and vulnerability to disease. The tree may die.

Light-colored plastic tree guards reflect the sun and keep trunk temperatures more constant. For the first five winters, cover tree trunks in November and remove the covers in early spring, before moisture causes fungal damage.

Mulching trees with 3 to 4 inches of wood chips or shredded bark will help minimize soil temperature shifts and retain moisture. Keep mulch away from the base of the tree to prevent rot and fungal problems. Instead of a “mulch volcano,” create a “mulch doughnut” with the tree trunk in the hole.

Tulips, daffodils and other bulbs should be planted soon to encourage root growth. Water if rainfall is sparse. Several inches of mulch will help keep the bulbs safely dormant during late-winter warm-ups.

Empty and clean flower pots, as freezing and thawing will crack containers, especially if they are full of soil. Potting soil and roots can go in the compost pile.

Plant material placed in a compost pile will not decompose before spring, so burn or bury any diseased plants. Most fungi will survive winter within infected plant material left in the garden. Pathogens that cause potato blight and tomato anthracnose, for example, may persist in the soil or on leaves, causing new infections when spring comes.

To clean birdhouses, scrub with a solution of one part bleach to nine parts water, then allow them to dry completely.