Oregon Hardiness Zone Map: What Is It?
The USDA (United States Department of Agriculture) defines Oregon growing zones as follows:
Ozark Mountains State Park, located in Missouri, is a popular destination for outdoor enthusiasts because it offers several hiking trails through the park. One such trail leads hikers along the Ozarks River Valley and into a small section of the park known as “the valley.” This area contains many old growth trees, some of which are over 400 years old. A few of these trees have been named “Old Man” and “Big Tree,” respectively.
These two large, ancient trees represent the oldest living things in the world and are considered to be at least 10 million years older than all other life forms combined.
According to the USDA, the valley is part of Oregon’s Zone 7b region, which encompasses parts of eastern Washington and northern Idaho. This means that the following conditions apply:
Average annual temperature between 55°F and 70°F (13°C and 25°C) Average precipitation between 0.2 inch (5 mm) and 1.2 inches (30 mm) each month
The USDA’s website provides a map indicating the 10 zones that were created by the USDA in order to help gardeners, farmers, and other plant enthusiasts easily determine what plants can survive under specific climate conditions. Oregon is comprised of four of these zones, which are 7a, 7b, 8a, and 8b.
Zone 7a encompasses the areas surrounding Oregon’s southern border and the state’s coastal waters. This area experiences slightly colder temperatures and more precipitation than the rest of the state. Zone 8b encompasses northern Oregon in an area that experiences hot, dry summers and cold, snowy winters. Zone 8a, on the other hand, is located in the eastern part of the state and consists of a land area that experiences hot, dry summers and cold, dry winters.
Zones 7b and 7a encompass Oregon’s coastal area.
With these facts in mind, you can narrow down your choices of plants for your garden by referring to the USDA Hardiness Zone Map (link). From there, you can determine which plants will thrive under the specific climate conditions found in your region.
Oregon Planting Zones: What Should I Know?
Oregon’s four planting zones are described briefly below.
Oregon’s zone 7a encompasses the southern portion of the state. The average summer temperature in this region is typically between 60-70 degrees and the average winter temperature is 33-40 degrees. In the winter, temperatures can drop to as low as 15 degrees. The area receives a lot of rain year round; however, it rarely gets too hot, with the exception of the coast, which can reach up to 80 degrees during the summer.
Oregon’s zone 7b encompasses most of the state and experiences similar conditions as zone 7a. The average temperature is 55-70 degrees in the summer and 25-35 degrees in the winter, with temperatures dropping as low as 15 degrees. Rain is common year round, though it’s a little more scarce in the summer months.
Oregon’s zone 8a encompasses the eastern part of the state and experiences a Mediterranean climate, with mostly wet winters and hot, dry summers. The average temperature here is 45-70 degrees in the summer and 25-40 degrees in the winter, though it can get much colder. Precipitation is scarce here, with areas around the mountains receiving the most rain, and even that isn’t more than about 15 inches a year.
Oregon’s zone 8b encompasses the state’s northernmost area, which also happens to experience the coldest temperatures. The average temperature here is 35-55 degrees in the summer and 15-25 degrees in the winter, with extreme temperatures of 20 below and 80 above not being uncommon. Rainfall is scarce here as well.
Overall, Oregon’s climate is a temperate one. It does experience very cold temperatures in the wintertime, but it also experiences very nice summers. Due to Oregon’s location on the west coast, it is also prone to earthquakes as well as tsunamis, which Oregonians need to be prepared for as well.
Plants That Thrive In Oregon (And Those That Don’t)
The best way to start a sustainable garden in Oregon is to begin by considering which plants are well suited for your area, as well as which are not. Some plants may seem tough and durable, but due to regional conditions they may not be able to survive the winter or consistently thrive year after year.
You should also be sure to choose plants that require the right conditions, such as partial shade or full sun exposure. Knowing whether your soil is acidic, alkaline or neutral will also help you determine which plants will have an easier time growing.
Begin by taking note of these few facts and rules, then combine them with the zone information provided by the USDA. You can then decide what types of plants will grow best in your specific area.
Call your local Cooperative Extension Office to find out which plants are native to your area. These plants are the most suited for your land and will grow best with little maintenance.
Your soil type can be determined by its color and how it reacts to certain chemicals, such as vinegar. If you pick up a handful of dirt and it forms a tight ball, your soil is alkaline. If it remains loose and falls apart, then your soil is acidic. Soil that remains in between the two is considered neutral.
Different plants require different soil types in order to grow, so this fact, in combination with the others, will help you determine which plants will be most successful on your land.
Designate areas of your garden or farm as specific zones for certain conditions. For example, one area can be designated as “full sun” and another as “shady.” While many plants will do fine in either condition, some need one or the other in order to survive. Zones will also help you easily identify plants that need specific care.
If You’re Stuck With A Desert, Try Nesting Material For Urban Creatures
Deserts are harsh places and many gardeners don’t have the patience to deal with the constant challenges of sand, sun and little water. Arizona is the biggest desert state in America, so if you’re a gardener living there, you’ve likely experienced challenges with gardening before.
If your property has a lot of open space, consider turning it into an urban wildlife haven by planting native wildflower species. Native plants require less attention and will attract birds, mammals and butterflies that thrive around such vegetation.
The key to success with this type of garden is to remember that most desert creatures, including humans, prefer lots of shade in the hottest parts of the day. This is why many cacti have thin, spindly branches and leaves that provide just enough coverage from the sun without casting too much shade on the ground below.
If you’re going to try your hand at gardening in an arid climate, try to keep these ideas and tips in mind. Remember that you’ll need to water your garden frequently and take other measures to keep plants thriving in the hot sun.
Gardening in other types of climates will require different sets of tips and tricks, but the basic principles of gardening are still the same no matter where you decide to try your hand at it.
If you’ve always wanted to grow your own fruits, vegetables and herbs but don’t have the time or space to do so, an option you might want to look into is container gardening in Ketchum. These types of gardens can be placed almost anywhere and require significantly less maintenance than traditional gardens. If you are interested in this type of gardening, there are garden centers in Ketchum that can help.
Sources & references used in this article:
Soils, seed-zone maps, and physiography: guidelines for seed transfer of Douglas-fir in southwestern Oregon by RK Campbell – Forest Science, 1991 – academic.oup.com
Mapping genetic variation and seed zones for Bromus carinatus in the Blue Mountains of eastern Oregon, USA by RC Johnson, VJ Erickson, NL Mandel, JB St Clair… – Botany, 2010 – NRC Research Press
Wildland–urban interface housing growth during the 1990s in California, Oregon, and Washington by RB Hammer, VC Radeloff, JS Fried, SI Stewart – International Journal of …, 2007 – CSIRO
Regional gradient analysis and spatial pattern of woody plant communities of Oregon forests by JL Ohmann, TA Spies – Ecological Monographs, 1998 – Wiley Online Library
Development of a new USDA plant hardiness zone map for the United States by C Daly, MP Widrlechner, MD Halbleib… – Journal of Applied …, 2012 – journals.ametsoc.org
Predictive mapping of forest composition and structure with direct gradient analysis and nearest-neighbor imputation in coastal Oregon, USA by JL Ohmann, MJ Gregory – Canadian Journal of Forest …, 2002 – NRC Research Press