Which Climate Zone Are You?
There are many ways to determine your climate zone and identify which plants will be happy growing in your garden and which will not. The most popular, the USDA (US Dept. of Agriculture) climate zone map, is based on minimum winter temperatures (we are Zone 9A). The Sunset Western Garden Book bases its climate zones using many factors like cold, heat, humidity, wind, the proximity to the Pacific Ocean, snow cover and growing season length (we are Zone 5). The reason Sunset’s zones are so comprehensive is because the Sunset book only concerns itself with the West. The Maritime Northwest Garden Guide from Seattle Tilth (www.seattletilth.org) dissects the maritime climate even further for northwest coastal and mountain zones. According to the Northwest Garden Guide, we are Zone A1 – the coastal range. Most books, seed catalogs and seed packets use the USDA zone information but rechecking what you want to plant with a more local zone map will help you become a more successful gardener.
All of these climate maps can assist the gardener but even within the most narrow, the Maritime Northwest Guide, we live and grow in many micro-climates. How many times have I driven from my house with clear skies and driven into driving rain just down the road? The same is true when cold weather arrives if you live in a more open area or if your home is surrounded by trees which help to block the wind.
If you are adventurous, you can fudge a bit on recommended zone plantings and see how the plants perform but no one wants to spend money on an expensive plant just to have it die after one severe winter or really hot summer. Others just don’t have the patience to take bed sheets outside to protect a plant from a freezing night or build a slip-shod, rickety structure to try and get a particular plant in the landscape through the winter. If you want to introduce a more sensitive plant for a particular look, try to give it some natural protection by planting it with a southern exposure in front of a wall (stucco or brick is best) under an eave so there will be more solar and reflected warmth. Care must be taken if the wall is white, however, because even roses that like lots of sun can get burned from the reflection of sun on a white wall.
Conversely, if you want tulips to bloom or apples and cherries to flower and set fruit, plant them in a less wooded area with exposure to the open sky. Planting a variety that needs the cold won’t be as successful if planted under a tree canopy. Planting a shrub that loves full sun should be located in an area that gets the most sun and not on the east or north side of your yard. If you choose a plant that needs some shade, a protected wall on the shady side of the house can work well.
Obviously, knowing your property and landscape is integral in choosing and placing plants. But even if you make some mistakes in planting your perennials, their dormant period in the winter will give you the chance to cut them back, dig them out and replant them in another area.
If you want to try some marginal varieties, you can always plant in containers and move sensitive plants into the house, garage or greenhouse during the winter. However, I have discovered that a lovely little citrus plant I have been dragging into the house for several winters, needing a larger and larger container, is just not a happy plant, barely blooms and isn’t worth the back pain to move it in and out.
Unlike landscape plants, vegetables are fairly easy to site because, first, you know they need as much sun as you can provide and, second, you can use many gardening tricks to extend the growing season. In our climate, we have a cooler winter environment that makes it ideal for berries and apples but doesn’t allow us to successfully produce peppers, eggplant and melons during our milder summer months. That’s where the tricks come in. Starting heat-loving tomatoes, eggplant and peppers inside, on a heat mat, under lights or in a greenhouse can give you a head start with those plants. Putting overhead protection like a cloche on a raised bed (raised beds warm up faster than ground-level planting beds) and starting seeds like lettuce and other cool-season vegetables early in the spring gives you a much longer growing season.
So have your climate zone numbers handy when you start to plan your vegetable garden or prepare to add new plants to your landscape. If they have a USDA zone designation, double check those varieties with a more local climate zone map to insure their happiness and your success.
by Sandra Stafford
Coos County Master Gardener of the Year
Coos County Master Gardener Association
OSU Extension, Myrtle Point, OR 97458