You may think of the Oregon landscape as having only tall pine trees covered with snow, but the state actually has a very diverse climate, with many types of garden plants. You will find locations from hardiness plant zones 4 through 9. The largest mild climate location in the state is west of the Cascade Mountains. The majority of this area is within planting zone 8, a mild climate in which many plants can grow and thrive.
Rhododendrons, including azaleas, are one of the most popular bushes of western Oregon. However, there are some varieties that grow within hardiness plant zones 4 through 8. This flowering plant is so popular that is celebrated in Florence, along the Oregon coast, during the Rhododendron Festival in May. The main thing to remember about these bushes is that they have a shallow root system, requiring frequent watering, especially during warm months. When temperatures get into the 90s, cool the entire plant down with a hose misting. Keeping mulch under the plant will help keep the roots moist. Some popular Oregon varieties include Grace Seabrook, Loderi Venus, Lern's Monarch, Bright Forecast and Everest.
Rose bushes do very well in many areas of Oregon. In colder locations, it is necessary to protect these plants during winter by cutting them back and covering the stalks with mulch. The mulch should be removed as soon as the temperatures are past freezing. Oregonians' love of roses is shown in the Portland Rose Garden. It shows 500 varieties that are grown in outlying areas of Oregon. Most of the bushes are in bloom between April and June. Roses, however, can be a bit high-maintenance because of plant diseases and insects. They attract aphids, spider mites and thrips. Roses are prone to powdery mildew, rust and blackspot. Some favorite rose varieties in Oregon include Prosperity, Amber Queen, Buff Beauty, Lavender Lace, Robin Hood, George Burns and Topaz Beauty.
A wide variety of evergreens (conifers) is abundant in Oregon. You will find them naturally growing throughout the state and prolifically in the Cascade Mountains. Some--Ponderosa pine and Douglas fir, for example--grow extremely tall and are not suitable as garden plants. However, the mugo pine is a bush that can be trimmed to be kept smaller or grown larger, up to 8 feet. Oregonians find this plant to be a nice way of bringing the natural greenery of the state into their garden. You may choose the compact mugo pine for a dwarf variety that grows no taller than 5 feet. The Mops mugo pine only grows to 3 feet tall. Both of these are perfect varieties to integrate into your garden or use as outlying plants.