PNW-climate

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Our region unlimited possiblities
The relationship between climate and gardening in the Pacific Northwest is undeniable. West of the Cascades is one of the very best places to garden in all of North America- our mild wet winters and warm dry summers allow us to succeed with plants from all over the world. We try to give the most specific cultural requirements we can and that includes hardiness ratings. Gardeners love to experiment, its fun to see what will live and what won’t- there are so many possibilites. We also believe that at least a cursory understanding of climate leads gardeners to more success. A LOT of information about our climate is based on dogma and even stranger, based not on fact, but opinion. What follows is an explanation of how we view this and how a gardener can understand climate to achieve a more interesting palate of plants and hopefully, a more diverse and satisfying experience.

Irrigation wet,wet,DRY,wet
The most important thing to understand in Western Oregon and Washington is the relationship between irrigated and non-irrigated gardening. Our climate is most defined by rainfall and WHEN that rain occurs. The majority of rain falls in the NON-GROWING season. West of the Cascades 75% falls between October 1 and April 1-. If you get 40 inches of rain a year that means that fully 30 inches of the yearly precipitation occurs when many plants are not even growing. The remaining amount (10 inches) is relegated to occasional falls during the growing season, mostly in late spring and early autumn. This climate pattern is not new. Weather records kept since the 1880’s show us that our climate is a winter-wet, summer-dry climate. Luckily, at our latitiude and proximity to the cool Pacific Ocean our period of high temperatures is relatively short. We think that intense summer irrigation in a climate with 6 months of clouds and drizzle, with only 4 months of pleasant weather is not what busy people want to do. Though, we do understand the pleasure of watering and bonding with the garden. Therefore, we offer a wide a selection of plants that give people alternatives to irrigation. Populations growth and climate change will mean that water will become more and more precious.

Xeric vs. low water
Plants that are truly adapted to periods of dry weather and soils are called Xeric Plants. It means that they cope with moisture loss in specific ways. Native shrubs such as Manzanitas adapt by holding their leaves perpendicular to the sun to avoid moisture loss. Other plants have leaves coated in fine hairs to cool the leaf surface and interrupt evapotranspiration. Plants that are not Xeric (Mesic) are adapted to locations and conditions where little drought stress ever occurs. We grow both types.
Our mild climate allows us to grow an amazing variety of plants, gardeners know that very tough situations require very tough plants. We think of it as a challenge to find the widest variety of plants to not only deal with tough conditions but to thrive. The old adage, the right plant for the right place holds especially true if you want a beautiful garden.

Plant Origins important clues about care
A plants origin, or where it occurs natively is a very important clue about the care that you give
it in a garden. We tend to lump plants together from all over the planet and then give them similar care.
This is a lot like putting animals from all over the world into the same pasture and then trying to
assert control. As you probably know this adds a lot of work, resources and time and the end result can be a little chaotic. Here’s where a little geographic background can be important. Start with a broad approach.
For instance, plants from Japan of which MANY are grown in the PNW are actually from a climate much different than our own. Japan experiences very moist and humid summers where precipitation is ample
from the warm monsoons, winters are cool and quite a bit drier. This is very similar to the Southeastern United States. Therefore, you can conclude that plants of Japanese origin probably appreciate regular irrigation during the summer and similarly plants that are native to the southeastern U.S.
Many plants from the summer dry, winter wet mediterranean region are popular in the PNW today. There is a good reason for our success with those plants. We too have a summer dry, winter wet climate. Plants of mediterranean origin and other mediterranean-type climates are maladapted to warm-wet summers. In that case we know that those plants, once established are best left unwatered during the summer. In our dry summer climate they thrive. Hence, Euphorbias, Viburnum tinus, lavenders, Daphnes and many other classic mediterranean plants are popular.

Biomes divisions within a climate.
Next, it is important to understand the ecotone or local conditions within a climate to which plants are specifically adapted. In the Pacific Northwest misunderstanding of the climate and local conditions have led many people to conclude that all plants native to our region will thrive in any location. WRONG.
Within all regions and all climates there are very different biomes. Elevation, exposure, permanently wet locations, sunny and shady areas differing soils. When you take into account these conditions you get a much better picture of where to place a plant, group plants with similar needs together and adjust the care accordingly. A good example of this is rock gardening where plants from all over the world occur in locations where they are adapted to expsoure, rapidly draining soils often with little nutrient value. So,
plants that grow at high elevations in the Alps, the Cascades or the Himalayas all experience these
conditions and can be grown together and treated in a similar way. Likewise, plants from woodland areas share the same requirements of shade and rich soil that does not dry out quickly. Recognizing these similarities in requirements is a sure step to success.

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