It is almost 2023, but you can still do some chores in your garden this year. In this episode of The Garden Thyme Podcast, we talk about the winter garden chores Rachel has been doing, and Mikaela and Emily have been putting off. We also talk holiday plant care (16:00), including caring for living trees (19:00) and fresh-cut trees (28:10).
The Garden Thyme Podcast is brought to you by the University of Maryland Extension. Hosts are Mikaela Boley- Senior Agent Associate (Talbot County) for Horticulture, Rachel Rhodes- Agent Associate for Horticulture (Queen Anne’s County), and Emily Zobel-Senior Agent Associate for Agriculture (Dorchester County).
Check to make sure the Christmas tree you purchase is fresh. Gently grasp a branch with your fingers and pull towards you. Very few needles should come off in your hand. The individual needles should be pliable when bent in half. Then raise the tree off the ground a few inches and hit the cut end of the trunk on the ground or pavement. If many needles shatter from the tree, it is a sign of dryness.
Keep the Christmas tree stand filled with water and check the level in the reservoir daily. There is no need to add preservatives to the water.
To keep poinsettias healthy keep them away from dry, drafty locations. Do not place near heat vents, doorways or drafty windows. Remove the decorative pot cover or make holes in the bottom of it to make sure the water drains from the container when you water.
Prune dormant shade trees that need to be pruned. Begin by removing all dead, diseased branches, and making any necessary cosmetic cuts. Do not cut branches flush with the trunk. Leave the branch collar (swollen area on the trunk of a tree or a larger branch) but do not leave a stub.
Incorrect pruning and over mulching
Topping (photo above) is the not the correct pruning technique to help control the size of a tree. Crown reduction, pruning entire branches at their point of origin, is recommended if a tree must be reduced in size.
Spotted lanternfly eggs. Photo: Lawrence Barringer, Pennsylvania Department of Agriculture, Bugwood.org
Be on the lookout for spotted lanternfly adults and egg masses. Report any finds to the Maryland Department of Agriculture.
Mulch your perennials after the first hard freeze. This helps to protect them from frost heaving caused by the freezing and thawing of soil. Mulch helps moderate temperature fluctuations, reducing this problem.
Powdery mildew may be seen now on many trees, shrubs, and perennials, like pin oak, roses, lilac, phlox, peonies, and monarda. This fungal disease favors high humidity but unlike other fungi does not require wet weather to thrive. It usually appears on plant foliage as a grayish, powdery coating on upper leaf surfaces. When possible select resistant cultivars. No chemical control is necessary.
Poison ivy leaves will begin to turn red this month. Don’t be fooled by their fall color change, the leaves are still very irritating. Do not handle or shred the leaves and do not burn the vines.
Before moving houseplants back indoorscheck plants for ants, earwigs, pillbugs, and other nuisance insects. Wash off insect pests or apply a labeled houseplant insecticide to control any plant pests such as aphids, scales, spider mites, and mealybugs.
Japanese beetles may be feeding heavily at this time. Brush the beetles into a bucket of soapy water held underneath foliage or branches. The use of Japanese beetle traps near your plants is not recommended. Studies show that traps can attract more beetles to your landscape resulting in increased damage.
Consider planting groundcovers where grass won’t grow such as shady areas, around tree roots, and on steep slopes. Select plants based on the amount of sun or shade the site receives.
Sow seed for fall transplants of broccoli, kale, turnip, and cauliflower in flats or containers by the 3rd to 4th week in July. Late crops of squash, beans, and cucumbers can be direct sown into your garden through the end of July.
Bagworm larvae are hatching out this month and constructing new bags. Look for the little bags moving around on evergreen trees and shrubs and be prepared to spray infested trees with the microbial insecticide, B.t. between now and mid-July.
Young tomato plants may be exhibiting symptoms of various leaf spot diseases such as septoria and early blight. Remove badly infected lower leaves, keep a thick organic mulch around plants and avoid overhead watering.
Monitor houseplants kept indoors for mealybug, spider mites, aphids, whitefly, and scale. If houseplant pests are a problem consider spraying with a labeled horticultural oil or insecticidal soap. If possible, move the plants outside before spraying and when dry, move them back indoors. Discard heavily infested plants.
If your azaleas, rhododendrons, and other spring-flowering shrubs are growing too large, prune them after they bloom.
Thin out interior boxwood branches to improve air circulation and reduce disease problems such as volutella canker. Also, look out for boxwood blight.
Move houseplants outdoors after the danger of frost has passed. To avoid sunscald, first place them in a shady location and over a period of two weeks or so to gradually introduce them to more sunlight.
Pinch the blooms from flower and vegetable transplants before you set them out. This will help direct the plants’ energies to root development and will result in more productive plants. Gently break up the roots of root-bound transplants before planting.