Rountree - Growing roses in the Pacific Northwest: 90 best varieties for successful rose gardening

I dont know whether nice people tend to grow roses or growing roses makes people nice.

ROLAND A. BROWNE

When I moved to the Seattle area 15 years ago, I knew that this area had a reputation for raining every day. So, as I was house hunting, I thought it was very funny that some properties included a sprinkler system. I quickly learned, however, that most of the region west of the Cascades experiences light rain from October through March, the months when it receives two-thirds of its average annual rainfall of 37 inches. Precipitation in the mountains is much higher, typically exceeding 100 inches. Summers are dry and warm, but there are periods of drizzle, fog, and clouds. It can seem as if its not necessary to provide supplemental water to the garden during the summer, but this type of drizzle doesnt penetrate into the root zone of plants; therefore, much to my surprise, some type of sprinkler system is a major bonus!

Contrasts in the Pacific Northwest climate can be stark because of the Cascade Mountains, which create a barrier between the maritime climate influences to the west, where temperatures are generally mild year-round, and the continental climate influences to the east, where there is more sunshine and larger daily and annual ranges in temperature.

Temperature extremes west of the Cascades are moderated by the adjacent Puget Sound, greater Pacific Ocean, and Lake Washington. Most Pacific storms are blocked by the Olympic Mountains, and Arctic air by the Cascade Range. High temperatures in winter are usually in the 40s Fahrenheit with lows in the 30s. Summer temperatures average highs in the 70s Fahrenheit and lows in the 50s. Temperatures are somewhat higher and lower the farther you are from the water, and within the region there are numerous microclimates.

The challenges of growing roses in this climate include keeping the foliage dry while keeping the roots watered during summer months; this will be discussed in .

Average annual precipitation is generally less than 20 inches east of the Cascades, with some places receiving as little as 7 inches. Annual and daily temperature ranges there are 15 to 25 degrees Fahrenheit warmer in the summer than those west of the Cascades, but the nighttime temperatures are cooler. Winters are colder, with snow more common at lower elevations. (See in A Guide to Basic Rose Care in the Northwest.)