I’ve been remembering my move up here to Clark County from Oakland CA in 1989. Most people didn’t have home computers then and the Internet was just being developed. I was new to the area, hardly knew a soul, didn’t know my way around, and I was desperate to garden in my new home. I spent a lot of time with library books and maps.
So, this is for the newly relocated, or perhaps you are just new to gardening. Here is some information to help you get started gardening in Clark County.
Did you know that our continent is classified in ‘eco-regions?” Much of Clark County WA is part of the Willamette Valley Eco-Region 3. We are at the northern tip of the Willamette Valley which is characterized by “mild, wet winters; warm, dry summers; forested foothills, alluvial valleys; and fertile soil.” We are further divided and classified as Eco-region 3a Portland/Vancouver Basin. On the eastern outskirts of the county is Eco-region 4a – Western Cascades Lowlands and Valleys.
The descriptions on the website give an idea of what was native to the area before urbanization. This is especially useful if you plan to include native plants in your landscaping.
The USDA zone for Clark County ranges from 7a -7b (foothills) to 8a – 8b (valley/flatlands). If you are familiar with the Sunset Climate zones we are Sunset zone 6 which includes the Willamette and Columbia River Valleys.
Although we sometimes get a late frost in May, mid to late April is generally the last frost for the area. Early to mid October is listed as the first frost date although the last couple of years it was mid November on the west side of Vancouver.
According to US Climate Data the average rainfall for Vancouver is 41 inches. This has been consistent over the years. Average snow: 2 inches. This has been typical in the past but the last couple of winters has seen more snow on the valley floor although it didn’t last more than a few days. Higher elevations of course will see more snow.
Temperatures listed for Vancouver: annual high: 62.1, annual low: 41.8, with the average temp. as 51.95. Our summers have definitely been warming up with 100-degree days for a few days at a time. Enough to consider drought resistant plants for a summer garden.
The degree of cold or heat depends on where you live in Clark County. I find the west side, and downtown Vancouver, to be warmer and less windy than the east side. The east side is impacted more by the influence of the Columbia River Gorge with icy conditions in winter and the warm dry wind in late summer.
Soils vary so it’s a good idea to have a soil test done by a local lab. Contact the WSU Master Gardener Extension for information on this. In the meantime you can also get an idea from the USDA Web Soil Survey. The information is based on data gathered over the years and will help you understand the existing soil conditions for your area. Follow the directions in the four steps outlined on the website. The result for my street address came out as 68.2% sand, 24.3% silt, 7.1% clay. It was spot on, I do have sandy loam soil which drains fairly quickly. This doesn’t replace an actual soil test done for specific soil quality but I found it very helpful and just plain interesting to know the geology of our area.
Of course there is nothing like talking to other local gardeners. The folks I go to for that are the WSU Clark County Master Gardeners and the Clark County chapter of the Hardy Plant Society. These folks love to help and encourage other gardeners. See my Resources page for more information.
With that, happy gardening in Clark County WA!