As the days get longer the list of Oklahoma gardening activities we can tackle gets longer.
We have experienced some serious winter temperatures this year and many of our broadleaf shrubs are showing winter burn, especially if they faced single-digit temperatures in dry soil. I dug holes last weekend to plant some trees and was shocked at how dry the soil was, not just at the surface but 6, 12 and 18 inches deep.
If you have not watered your trees, shrubs, perennials and pansies lately, please consider hooking up hoses long enough to give any living plant material a good soaking. When plants are living in dry soil and we get frigid temperatures with low humidity, plants can become dehydrated and literally “freeze-dry” or get the winter burn that detracts from their ability to survive or at the least will limit their energy for spring growth. After either a good rain or this winter watering is a good time to feed your ornamental, fruit and nut trees as well as shrubs.
This is also the start of the season to apply pre-emergent herbicides, which act as birth control for crabgrass and warm-season weeds before they germinate or sprout. Apply as just a weed killer or combined with a fertilizer to act as the popular “weed and feed” treatment for your lawn.
The Oklahoma State University Extension Service for many years has recommended you apply the pre-emergent weed killer by the time the flowers are done on the yellow forsythia shrubs or our native Redbuds. These weed killers will control most weeds that try to germinate for the next eight to 10 weeks after being applied and watered in.
If you plan to plant any bare-root ornamental or fruit trees, roses, vines or berries, they should be planted in February or March with the best time most years from mid-February to mid-March. You can plant container-grown trees, berries and roses most anytime the ground is not frozen.
This is a good time to spray dormant oil on deciduous trees and shrubs when the temperature is above 40 degrees to control mites, galls, aphids and many other overwintering insects. The dormant oil suffocates many of these insects and can dramatically reduce insect pressure later in the growing season as there will be fewer insect parents birthing thousands fewer young insects to feed on your crops.
We are just beginning the season to plant cool-season vegetable crops, especially many of the root crops that grow underground like potatoes, radishes and onions. In central Oklahoma, we often say the prime time to plant seed potatoes, onions sets or onion plants is Valentine's Day to St. Patrick's Day. Southern Oklahoma warms a little earlier and can start now as well the early birds in central Oklahoma.
You can also plant asparagus crowns, horseradish, rhubarb, spring-bearing or ever-bearing strawberries and a wide selection of berries. Consider adding some grapes, blackberries, raspberries, blueberries, youngberries, boysenberries and gooseberries to your yard. It is a lot of fun to pick fresh healthy berries in your own yard to pop in your mouth or to add to your dinner table.
February is the best season to prune shade trees, hedges, roses and summer flowering shrubs. Don't prune spring flowering shrubs like quince and forsythia until after they flower later this spring or you will cheat yourself out of much of their beautiful spring show.
Rodd Moesel serves on the Oklahoma State University Agriculture Dean's Advisory Committee. He is a former president of the Oklahoma Greenhouse Growers Association. Email garden and landscape questions to email@example.com.