Region Description: Inland Northwest

Regional Gardening Reports :: National Gardening Association

Region Description: Inland Northwest

Zone Map
USDA Hardiness Zones
4 to 8
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AHS Heat Zones
4 to 8
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Sunset Zones
1 to 3
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Major Cities

Bend OR, Boise ID, Cedar City UT, Ely NV, Grand Junction CO, Klamath Falls OR, Nelson BC, Provo UT, Reno NV, Salt Lake City UT, Spokane WA, Twin Falls ID

The Region

Inland Northwest includes the high desert areas east of the Cascade and Sierra Nevada mountains. Following a line running south along the spine of these mountains to central California. It then heads east to just north of Las Vegas, includes some of the mountains of northern Arizona, crossing through Utah to Grand Junction, Colorado. Heading north through western Wyoming and along the Montana-Idaho boundary into Canada.

The Climate

Elevation dictates much of the climate in this regions. High elevation areas feature cold winters and short summers. Low elevation river valley areas are milder and wetter. Rainfall averages under 10 to 20 inches a year in parts of eastern Washington and Oregon and most of Nevada and Utah, to 30 to 40 inches a year in the mountains and valleys of Utah and Idaho. High winds and snowfall dictate the winter weather. Spring can happen suddenly, but so can a late spring snowfall. Summers can be sunny, hot, dry, and short.

The Growing Season

The growing season runs about 150 days from May to October in high elevation areas with a constant threat of frost even in summer. Not only the absolute winter cold, but intense sun, high winds, and lack of constant moisture allow only the hardiest plants to survive. Native plants adapted to high elevations such as columbines do best. Windbreaks often are used to protect new plantings. In low land valleys areas, the milder temperatures allow for a longer growing season (up to 200 days) and the ability to grow a broad range of temperate plantings from onions to boxwood to apples.

View this week's Regional Report for
Inland Northwest, High Desert »

Published by the National Gardening Association,


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