Seattle's climate is influenced by the Pacific Ocean and the nearness of Puget Sound. These large bodies of water create mild summer and winter weather. There is an average of one to 14 days of temperatures that are above 86 degrees Fahrenheit. The summer average temperature is 75 degrees F. and the winter average temperature is 42 degrees F. Rainfall in Seattle averages 36 inches a year. Seattle's growing season lasts 150 to 180 days. Seattle's climate is a combination of USDA winter hardiness zones 7 and 8.
Coral bells (Heuchera sanguinea) are spreading perennials with evergreen foliage. The low, mounding clumps of green leaves spread 1 foot wide. Bell-shaped blossoms cluster together on 2 foot tall flower stalks. The flowers form color spots of red, pink and white. Coral bells prefer good-draining soil, but do not do well in clay soil. Removing the dying blossoms encourages this perennial flower to bloom again in the fall.
Japanese wisteria (Wisteria floribunda) is a rapidly growing deciduous vine that grows 35 feet long in full sunlight. The leaves are made up of 13 to 19 leaflets. The fragrant blooms form draping clusters in 9 to 20 inch long flower spikes. The flowers are lavender, purple, white and pink in color. Japanese wisteria climbs in a clockwise direction.
Peonies (Paeonia spp.) are slow growing perennials with lance-shaped leaves that spread 3 feet wide. Flower stalks grow 3 feet tall and produce 3 to 6 inch blossoms in red, pink, white and multi-colored. These fragrant flowers appear in the early summer. Peonies do not bloom in deep shade. Always check the cold requirement for your choice of peony since USDA zone 8 may not receive enough cold weather to trigger some varieties to blossom.
Royal grevillea (Grevillea victoriae) is an evergreen shrub that grows upright to 6 1/2 to 10 feet tall. The oval leaves have smooth, gray-green tops and hairy, silvery bottoms. In the spring and summer, orange-red flowers hang in clusters. This bush is an Australian native, but grows well in good-draining sites in the Pacific Northwest.
Witch hazel (Hamamelis spp.) is a deciduous shrub that flowers during the winter. The 1/2 to 3/4 inch blossoms are yellow, gold and red with four narrow petals. Occasionally this shrub begins blooming in the fall. This 6 to 15 foot bush produces green leaves that turn yellow with purple and red tints. Choose a witch hazel bush when it is fully in bloom. This lets you check for a scent that you enjoy. Some types are sweetly fragrant while others are not.