Imagine a single rosemary plant so big and lush that you can’t wrap two sets of arms around it. I saw this imposing shrub a few weeks ago in a garden on San Juan Island north of Seattle. As it happened, the plant’s owner, who referred to it as “the rosemary bush from hell,” had even pruned it back to keep it from overtaking the rest of her garden.

During recent visits with gardeners in the Pacific Northwest, I thought sheepishly of the more modest rosemary plants in my herb bed in Kansas, which will do well to grow to my knee before the autumn frost ends their outdoor growing season. In the Seattle area, the temperate climate allows rosemary to be a year-round herb that becomes more robust with each passing winter. On a street corner in Friday Harbor the rosemary is voluminous enough to be used as a hedge.

But even with the enticement of mutant rosemary shrubs, the ability to grow artichokes, a season for greens and cole crops that lasts deep into the summer, and ample rainfall, I’d be hard-pressed to give up gardening in northeast Kansas. There’s something to be said for the broiling Midwestern heat.

Different Zones

The Puget Sound gardens I visited were located in Zone 9, while most Kansans grow their vegetables and herbs in Zone 5. The U.S. Department of Agriculture makes these hardiness designations based on the low temperature in winter. The thermometer in Zone 9, according to the USDA, doesn’t register below 20 degrees, while the lowest winter temperature in our hardiness zone can fall well below zero. That’s why a woody herb like rosemary is a perennial in Seattle but turns into a Popsicle in Kansas.

For Puget Sound gardeners, there’s a downside to this rosy scenario, though. The Pacific Northwest is in the same hardiness category as many parts of the South, including the southern tip of Texas and the citrus region of central Florida. But unlike those other areas of Zone 9, the Pacific Northwest doesn’t have a hot growing season.

Need for heat

What this means is that home gardeners in the Puget Sound area have a more difficult time with true summer crops. They have skimpier tomato harvests and often must pick a good many of their tomatoes green. With much cooler soil temperatures, they can’t grow okra, and bell peppers struggle to attain the girth of ping-pong balls. I even saw basil growing inside a Wall-o-Water insulation cone in mid-June.

Yet vegetable gardens are a backyard fixture on the islands in Puget Sound. Many gardeners compensate for the cool soil temperature, which struggles for much of the growing season to stay above 60 degrees, by planting vegetables in raised beds crafted from 12-inch lumber.

The raised beds also create a line of defense against slugs, which are nocturnal garden predators that more than offset the lack of hot-weather garden pests we battle in Kansas. I never imagined that grasshoppers and bean beetles were a lesser evil, but there it is.

My cousin, who gardens on Vashon Island, 15 minutes by water from Seattle, wraps 4-inch strips of copper flashing over the top edge of his raised beds to form the ultimate slug barrier. Copper is toxic to slugs and unless the slugs can somehow bypass the edge of the bed, his vegetable plants are spared.

One evening we took a flashlight out to his garden where we spotted little colonies of slugs gathered under the mulch along the sides of the raised beds.

Slugs had somehow found their way into one of the raised beds, which can happen if a climbable weed pops up alongside the bed. Slugs like beer, so my cousin had set traps in that bed by burying plastic cups of beer in the soil. If the traps work, the slugs drop into the beer and drown.

Raised beds also seem to provide an obstacle to gophers, which burrow into the garden but don’t bother the boarded-off areas.

At least one of the challenges of gardening in the Pacific Northwest is the same as ours. My cousin has an 8-foot deer fence around his garden, which is a fairly common sight in rural and suburban areas on the islands. Deer are even an issue for some urban gardeners who live near the woods.

Give me a 5-foot tomato plant loaded with vine-ripened fruit and I’ll manage with the Kansas heat and drought and bugs. All in all, the Pacific Northwest is a wonderful place to visit, but I wouldn’t want to garden there.