Time to prune those flowering plants

Each month, the OSU Extension provides reminders of essential garden chores, such as fertilizing, pest control, planting and maintenance.

The recommendations in this calendar are not necessarily applicable to all areas of Oregon. For more information, contact your local Extension office.

The Oregon State University Extension Service encourages sustainable gardening practices. Preventive pest management is emphasized over reactive pest control. Identify and monitor problems before acting and opt for the least toxic approach that will remedy the problem. The conservation of biological control agents (predators, parasitoids) should be favored over chemical controls.

Trade-name products and services are mentioned as illustrations only. This does not mean that the Oregon State University Extension Service endorses these products and services or intends to discriminate against products and services not mentioned.

Planning

Construct trellises for tomatoes, cucumbers, pole beans and vines.

Maintenance and cleanup

Prune lilacs, forsythia, rhododendrons and azaleas after bloom.Fertilize vegetable gardens one month after plants emerge by applying a side dressing alongside rows.Harvest thinnings from new plantings of lettuce, onion and chard.Pick ripe strawberries regularly to avoid fruit-rotting diseases.Use organic mulches to conserve soil moisture in ornamental beds. An inch or two of sawdust, bark dust or composted leaves will minimize water loss through evaporation.After the normal fruit drop of apples, pears and peaches in June, consider thinning the remainder to produce a larger fruit crop.Make sure raised beds receive enough water for plants to avoid drought stress.Mid-June: If green lawns are being maintained through the summer, apply 1 pound of nitrogen per 1,000 square feet to lawns.Central Oregon and higher elevations of eastern Oregon: Frost can still be a concern during cold nights. Protect young vegetables from frost by having row cover (frost cloth) on hand. Place over crops when needed. Use season extenders, such as walls of water, around tomatoes and other tender plants.If you want a green lawn, water frequently during periods of heat and drought stress. Irrigate 0.25 inches four to six times per week from June through August. Measure your water use by placing an empty tuna can where your irrigation water lands. When the system is running, record the time it takes for the water level in the can to reach 0.25 inches.

Planting and propagation

Plant dahlias and gladioli.

Pest monitoring and management

Use chemical controls only when necessary and only after thoroughly reading the pesticide label. First consider cultural, then physical and biological controls. Choose the least-toxic options, and use them judiciously. Some examples include insecticidal soaps, horticultural oils, botanical insecticides, and organic and synthetic pesticides.

Central Oregon and high elevations of eastern Oregon: Manage weeds while they are small and actively growing with light cultivation or herbicides. Once the weed has gone to bud, herbicides are less effective.First week: Spray cherry trees for cherry fruit fly, as necessary, if the fruit is ripening. Also, spray for codling moths in apple and pear trees, as necessary. Continue using pheromone traps for insect pest detection.Learn to identify beneficial insects and plant some insectary plants — such as alyssum, Phacelia, coriander, candytuft, sunflower, yarrow and dill — to attract them to your garden. Check with local nurseries for the best selections. For more information, see Encouraging Beneficial Insects in Your Garden.Squash and cucumber blossoms begin to drop. This is nothing to worry about. Cherries may also drop fruit, which is also not a major concern.Monitor azaleas, primroses and other broadleaf ornamentals for adult root weevils. Look for fresh evidence of feeding (notching at leaf edges). Try sticky trap products on plant trunks to trap adult weevils. Protect against damaging the bark by applying the sticky material to a 4-inch-wide band of poly sheeting or burlap wrapped around the trunk. Mark plants now and manage root weevils with beneficial nematodes when soil temperatures exceed 55 degrees Fahrenheit. If root weevils are a consistent problem, consider removing plants and choosing resistant varieties.Control garden weeds by pulling, hoeing or mulching.Control aphids on vegetables by hosing them off with water or using insecticidal soap or a registered insecticide.Watch for 12-spotted beetles on beans, cucumbers and squash. Look out for cabbage worms or flea beetles in cole crops (cabbage, broccoli, Brussels sprouts). Remove the pests by hand or treat them with registered pesticides.Birch trees dripping a sticky fluid from their leaves means aphids are present. Control as needed.Use yellow sticky traps to monitor for cherry fruit flies. Spray cherries at appropriate intervals about one week after the first fly is caught.Last week: Second spray for codling moth in apple and pear trees, as necessary.Continue monitoring blueberry, strawberry, cherry and other plants that produce soft fruits and berries for spotted wing drosophila. If these pests are present, use an integrated and least toxic approach to manage the pests. To learn how to monitor and manage spotted wing drosophila.

Indoor gardening

Move houseplants outdoors for cleaning, grooming, repotting and summer growth.