An essential part of having a successful garden is to understand the climate in your area. In Seattle, roughly half of the annual precipitation falls between Nov. and Feb. in contrast --only 8% falls between June and August which provides Seattle with amongst the driest summers of any city in North America. This trend of wet winters and dry summers is common also to Southern Europe and is termed a “Mediterranean Climate”. This in combination with the presence of the Pacific Ocean and Puget Sound which buffers Seattle from cold winters – enables Seattleites to grow an enormous diversity of plants.
Just because a plant is ‘Hardy’ in Seattle, and can therefore survive our winters, does not necessarily make it a simple to grow. It's water requirements during the summer must also be met, for it to flourish. Growing plants that are adapted to the rainfall patterns in your area is an excellent way to reduce your cost and time of irrigation without the need to severely limit your plant palette. There are many areas in the world with a Mediterranean climate including parts of West and South Australia, South Western South Africa, Central Asia and Central Chile and Southern Europe that have given us staple plants such as: Rosemary, Lavender and Hebe as well as the more unusual Kniphofias, Grevilleas and the stunning Chilean Fire Bush (Embothrium coccineum)
TIP: Mediterranean plants need good drainage during the winter months. If you have heavy clay soil consider using them in containers for drought tolerant summer color and scent.
For inspiration: visit the Pacific Connection Gardens at the University of Washington Arboretum http://depts.washington.edu/uwbg/gardens/wpa.shtml
For information: on everything weather related in the region