Gardening in Chelan and Douglas Counties in North Central Washington can be a very rewarding experience, but our hot and arid climate creates some challenges that affect our gardening practices and decisions.
Weather and soil conditions east of the Cascades are important factors to consider when choosing and maintaining trees, shrubs, lawns, vegetables and flowers. Residents new to the arid climate, high summer heat, and generally low organic matter in the soil will find more success growing plants when aware of these conditions. An array of plants, such as tomatoes and melons, benefit from the heat. In contrast, even with careful placement, a favored dogwood risks an appearance marred by leaves scorched by hot sun and dry heat.
Take these conditions into account when designing a landscape, garden, or irrigation system, and choosing and maintaining plants.
WSU Master Gardener volunteers are ready to help you learn about gardening and answer your gardening questions.
Average Temperatures
- Wenatchee: Summer high- above 100°F’ / Winter low- min. -15°F /
- Wenatchee: Average first frost date: Oct. 30 / Safe date for spring planting: Mother’s Day
- Leavenworth: Summer night average: below 65°F
- Leavenworth: Average first frost date: Sept. 18 /Safe date for spring planting: May 30
- Degree Days – check degree days for insect control, plant management, at weather.wsu.edu
Annual precipitation (rain and snow)
- Wenatchee: 8-11 inches
- Chelan: 10-15 inches
- Cashmere: 8-12 inches
- Leavenworth: 15-25 inches
- Humidity: low
Growing season
- Wenatchee: average 119 days
USDA Hardiness zone
- Wenatchee: near the river: 7b (min. 5°F). Higher elevations, Chelan and Leavenworth tending to zone 7a – 6b (min. -0°F to -5°F) [new map in 2023]
American Horticultural Society Heat Zone
(Number of days above 86°F)
- Wenatchee & Chelan: zone 6 (45-60 days)
- Leavenworth: zone 5 (30-45 days)
Sunset Climate Zone Maps
– these maps take into account the length of growing season, timing and amount of rainfall, winter lows, summer highs, wind, and humidity. Our area is on the Sunset map of Eastern Washington, Eastern Oregon, and Idaho.
- Wenatchee & Chelan: zone 2
- Leavenworth: zone 1A
Wind
- abundant in spring and summer, can be drying
Soil
- pH 7.0 – (neutral tending to alkaline)
- High in organic matter in forested areas. Common in Leavenworth
- Low in organic matter and water holding capacity in silt, sand and clay, common in Wenatchee
- Soil composition varies – majority is silt and sand but can have pockets of clay
- Erosion – during acute rain and wind storms
- Home Gardeners Guide to Soils & Fertilizers– a Washington State University publication
- Find your soil type– at the USDA’s National Resource Conservation Service site. After you find your property, click on Map Unit Name to read details of your soil characteristics.
Plants
- Heavy snow and wind can break branches of flowering dogwood, Japanese maples, Austrian Black Pine, Scotch Pine (trees and shrubs with brittle wood)
- Drying, hot summer winds can cause leaf scorch on dogwood trees and Japanese maples not shaded by taller trees
- More summer heat benefits melons, squashes, pit fruits, tomatoes, beans
- Smaller range of insects and diseases – probably from winter kill
- Horticultural Myths and more by Linda Chalker-Scott, PhD, WSU Puyallup Research and Extension Center
- Treated woods in the garden- What is safe?– Penn State Extension
Maintenance
- Lawns: must provide water in the summer.
- It is better to irrigate longer so water penetrates to the plant’s full root depth rather than several shorter sessions. Adjust inches per week based on temperature. To observe the depth of roots and water penetration, sink a shovel or spade into the lawn to a 8-10 inch depth, after watering the lawn. Read more about lawn care.
- Cut grass to 3 – 3.5 inches in hotter months to shade and cool roots.
- Group plants of similar water demands, and water by irrigation zones.