May Section copy - WSU...
Transcript of May Section copy - WSU...
Planning/Maintenance/ Activities
Average Last Frost Dates: Ellensburg: 11 May Cle Elum: 24 May Prepare and prime irrigation system for summer.
If needed, fertilize rhododendrons and azaleas with acid-‐type fertilizer after they bloom. If established and healthy, their nutrient needs should be minimal. Remove spent blossoms.
Use a soil thermometer to help you know when to plant vegetables. When the soil is consistently above 60 degrees, some warm season vegetables (beans, sweet corn) can be planted in late May.
Apply 2 to 4 inches of mulch around plants. Apply over well-‐watered, weed free soils. Mulch discourages weeds, conserves moisture, and controls temperature Iluctuations in soil.
Stake tall and Eloppy perennials (peonies, delphiniums) as they grow.
After the soil warms up enough to activate soil microbes, you can apply organic fertilizers such as compost, manure, Eish emulsions, blood meal and bone meal.
Pest Monitoring & Management If unknown problem occurs, contact Kittitas County Master Gardener plant diagnostic clinic for identiEication and management options.
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.
Monitor aphids on Eirs, roses, arborvitae, maples, strawberries and ornamentals. If present, control options include washing off with water, hand removal, beneIicial insects, or using registered insecticides labeled for the problem plant. Read and follow all label directions prior to using insecticides. In lieu of using registered insecticides, promote natural enemies (predators and parasitoids that eat or kill insects) a longer-‐term solution for insect control in gardens.
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Leafrolling worms may affect apples and blueberries. Prune off and destroy affected leaves.
MAY
Spittle bugs may appear on ornamental plants as foam on stems. In most cases, they don't require management. If desired, wash off with water or use insecticidal soap as a contact spray. Read and follow label directions when using insecticides, including insecticidal soap. Control cabbage worms in cabbage and cauliElower, 12-‐spotted cucumber beetles in beans and lettuce, and maggots in radishes. Control can involve hand removal, placing barrier screen over newly planted rows, or spraying or dusting with registered pesticides, labeled for use on the problem plant. Read and follow label directions when using insecticides. Tiny holes in foliage and shiny, black beetles on tomato, beets, radishes, and potato indicate Elea beetle attack. Treat with Neem, Bt-‐s, or use nematodes for larvae. Read and follow label directions when using insecticides. Prevent root maggots when planting cole crops (cabbage, broccoli, collards and kale) by covering with row covers or screens, or by applying appropriate insecticides. Read and follow label directions when using insecticides. Monitor rhododendrons, 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 on a 4-‐inch wide band of poly sheeting or burlap wrapped around the trunk. Mark plants now and manage with beneIicial nematodes when soil temperatures are above 55 degrees Fahrenheit. If root weevils are a consistent problem, consider removing plants and choosing resistant varieties.
Control slugs with bait or traps and by removing or mowing vegetation near garden plots. Monitor blueberry, raspberry, strawberry and other plants that produce soft fruits and berries for Spotted Wing Drosophila (SWD). Learn how to monitor for SWD Ilies and larval infestations in fruit. Check evergreens, especially spruces, for spider mites; treat as new growth begins. Place a white sheet of paper under branch and tap lightly, looking for moving pin-‐head size spots.
Lawn
Tackle lawn weed problems on warm days and continue to mow regularly. Weed-‐n-‐Feed products are fatal/damaging to broadleaf and needled plants and trees. Do not use Weed-‐n-‐Feed near the plants root zone. Always use weed killers according to label directions and use accurate measurements. Spot treat lawn weeds with broadleaf weed killers rather than spraying the entire yard.
You can still aerate or power rake an existing lawn and over-‐seed an old lawn.
Start infrequent deep watering of lawns. New lawns must be watered daily until they germinate. Then it is time to cut back and water deeply but less frequently.
Woody Landscape Plants & Fruit Trees
Prune spring Elowering trees and shrubs after the Elowers fade. Flowering almond, quince, forsythia, and lilac stay more compact and bloom better with annual pruning. Cut out dead or broken branches and up to one-‐third of older stalks.
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Avoid pruning oaks and elms during the growing season, typically early April through October. Oak wilt and Dutch elm disease are spread by sap feeding insects carrying the disease from tree to tree.
WAIT to prune birch, elm, maple, and walnut trees until late fall. Although harmless, these trees bleed sap on sunny days.
Thin fruits of apple (and other fruit trees if needed) about 3 weeks after petal fall. Apples should be spaced on the average of about 8 inches apart; peaches at 6 inches apart. If a large crop is set and no thinning is practiced, all fruit will be small and branches may break.
Plant balled-‐and-‐burlapped or container nursery stock trees, and water thoroughly.
Remove and destroy overwintering bagworms from landscape trees and shrubs.
Prune evergreens once new growth has begun to appear.
If summer and fall blooming perennials have become overgrown, dig them up and divide them.
Flowers, Vegetables and Small Fruit
Sow hardy annual Elowers outdoors in early May (sweet alyssum, bachelor buttons, calendula, cosmos, sweet pears). Wait until after the last frost and the soil has warmed before planting tender annuals (marigolds, portulaca, zinnias).
Pinch chrysanthemum and annual Elower plants to keep them compact and well branched. Start in the spring when the new growth is 4 to 6 inches long. Pinch all shoots and Ilower buds every two or three weeks until late June; continuing longer will prevent Ilower formation.
The plant will then grow new shoots and Ilower buds, and they’ll bloom in the fall—right when you most want a little extra color in your garden!
When selecting new roses, choose plants labeled for resistance to diseases. Fertilize roses and control rose diseases such as mildew with a registered fungicide.
Deadhead spring bulbs when they are done Elowering to direct energy back into bulbs. Do not remove foliage; let it die back naturally.
Plant perennials in your garden. Choose the right plant for the right location. Place mulch around your perennial bed, but no more than two inches.
Vegetable gardens. Begin harvesting early produce (asparagus, lettuce and onions to thin, spinach, and peas).
Remove blossoms from newly set strawberry plants. This will allow better runner formation.
Remove unwanted sucker growth in raspberries when new shoots are about a foot tall.
Use a soil thermometer to help you know when to plant vegetables. Wait until the soil is consistently above 70 degrees to plant tomatoes, squash, melons, peppers, and eggplant.
Hill up around potatoes as they grow. Use compost, or pine needles, or the like.
Thin seedlings of earlier planted crops such as carrots, lettuce, spinach, and beets, as they
emerge to their proper spacing. Remember to add Nitrogen as a side dressing to plants that need it.
Start pumpkins and melons indoors to transplant in early June.
Continue planting leafy greens, beets and carrots in small amounts for a staggered harvest.
Continue planting seeds and transplants such as cauliElower, cabbage, Brussels sprouts , artichokes, lettuce, squash. Some transplants may need protection if planted before the last frost in your area.
Make successive plantings of beans and sweet corn to extend the season and harvest.
As seedlings mature and transplants grow, increase watering duration and decrease frequency. Kittitas County is very windy in Spring and Summer, especially in the afternoon, so set timers to come on in early morning. This also allows plants to dry out and helps prevent certain diseases.
Begin to water fruit trees and berries deeply every week rather than every other week. Drip systems work well for this on berries.
Keep weeds out of garden and berries by lightly cultivating. Observe fruit trees for pests. If trees need treating this season, note time ‘till fruit ripens. Do not spray while bees are present. (See February calendar for Apples, Cherries, Pears, Plums, and Prunes spray schedules).
Gardening in Kittitas County
Gardening in Kittitas County presents many challenges and opportunities. While there are ample days of sunshine and nights that meet and exceed plants’ chilling requirements, there are extremes of heat in the summer and cold in the winter. Wind is a constant in all parts of the county and snow depth is a factor, especially in the higher elevations. Add to this the fact that Eastern Washington has an arid climate and most plants require additional regular watering, especially while becoming established. Last, but certainly not least, are the pests that prefer ones’ garden and orchard to their natural diet and would ravage these if homeowners did not use special precautions against them.
Kittitas County, not unlike many counties in Washington, has differences within the county with respect to rainfal l , e levat ion, and temperature. Therefore, the length of growing season is different depending on location. While the ground may be workable in Ellensburg (lower county) at the beginning of April, it may still be covered in a foot of snow in Roslyn (upper county).
While the lower county may require minimum winter protection for most crops, upper county requires maximum protection for most perennials that do not naturally grow there.
At higher elevations such as Ronald (2,349 feet), the average growing season is 90 days with last frosts in early June (approximately June 9th) and Iirst frosts in early September (approximately September 2nd); In Cle Elum (1,930 feet), the average growing season is 90 to 120 days with last frosts in late May (approximately May 24th) and Iirst frosts in the middle of September (approximately September 11th). Cle Elum receives about 22” of rain on average. At lower elevations such as Ellensburg (1,542 feet), conditions are much drier and frost-‐free days are longer. The average growing season in Ellensburg is about 120 days with last frosts in early May (approximately May 11th) and Iirst frosts around the end of September (approximately September 25th).
Ronald, Rosyln, and Cle Elum are rated USDA Zone 4 (-‐30ºF minimum temperature) while Ellensburg is rated at USDA Zone 5 (-‐20°F. minimum).
The authors of this e-‐book are using techniques deemed necessary for their particular region within Kittitas County. The reader’s to do list will be speciIic to their area and their particular climate. Be sure to check resources provided to determine speciIic climate area.
This calendar is a compilation of many sources of information. Many thanks for the outstanding guidance provided by: Washington State University Extension, Purdue University Cooperative Extension Service, The Morton Arboretum, Oregon State University Extension and many others as evidenced by the extensive use of hyperlinks.
By Laura Stanley and Barbara Raabe Kittitas County Master Gardener
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For more information: Contact the Master Gardener Diagnostic Clinic
May through September
WSU Extension OfIice 901 E 7th Avenue, Suite 2 Ellensburg, WA 98926
Phone (509) 962-‐7507
http://www.kittitas.wsu.edu