Cover Story Plant Life On Fitness Northwest Living Taste Now & Then Sunday Punch


Cold Truths
To garden well, we must know our place

"Garden where you live," says garden writer and philosophy professor Allen Lacy, considering this the most important advice he could give any gardener. I've pondered that declaration, wondering if he means we all need a dose of reality to knock Zen gardens or banana canna extravaganzas out of our systems. Does he mean we Northwesterners need to limit ourselves to growing firs and ferns?

I think he means that gardeners must first understand and accept the realities of their own soil, weather and topography. This is the starting place — whether we then use that knowledge to fashion Moroccan courtyard gardens, Balinese retreats or Northwest woodland scenes.

So, let's consider the hard, cold truths of our gardening realities. And cold is truer than we'd prefer: In recent years the American Horticultural Society has produced a heat-zone map, in contrast to the more familiar Sunset or USDA climate-zone maps, which are based on extremes of cold. Other factors affect plant growth: Plants supposedly die a slow and lingering death from too much heat. But don't worry about it. The Seattle area comes in No. 2 on the heat-zone map, registering only 1 to 7 days each year over 86 degrees. We know that; how many evenings did you eat dinner outdoors last summer?

If we're Zone 2 on the heat map, most Seattle-area gardens are Zone 5 on the Sunset map and Zone 7 or 8 on the USDA map. This means that minimum temperatures rarely go below the 20s, with the extreme lows ranging from 10 to 17 degrees. It also means we're at nearly zilch in the way of heat accumulations (why tomatoes are still green come September) and have a growing season between 200 and 250 days, depending on whether you live close to water or higher up in the foothills. Even freeze damage isn't an absolute, but depends on timing. A sharp freeze in November may kill off a slew of borderline plants, while several days of the same temperatures in January, once plants have hardened off, cause much less devastation.

Now In Bloom
Sweetgums keep their leaves longer than most deciduous trees, in a display of autumn color that lasts clear into winter. The broadly lobed leaves turn shades of yellow, orange and purple all at the same time. Liquidambar styraciflua 'Gumball' tops out at 15 feet, while 'Moonbeam' grows slowly to 30 feet.
And then there is the concept of microclimates, which come with the lay of the land, and can be influenced by placement of fences, houses and paving. Whole neighborhoods near Puget Sound have their own warm little microclimates, where palm and banana trees grow large. You can clue in to your own garden's microclimates by paying attention to where the wind whistles through, noticing where frost lingers or where heat gathers and reflects to create warm pockets for ripening figs or bringing tropicals into early bloom. My lavender hedge flourishes because it grows up in pure fill sand against a house wall. And I can finally grow ceanothus, after killing it in earlier gardens. It grows among heat-reflecting rocks on a steep bank — turns out it wasn't the low temperatures but the soggy soil that did it in.

When it does start raining in November, we get a lot of it, and the heavy clay soil that is unfortunately prevalent throughout the region becomes waterlogged. More of our plants die from root suffocation than from the cold.

We think of our climate as rainy all year 'round, but we have a distinct droughty period between July and mid-September. Some have gone so far as to call our climate Mediterranean. Living here my whole life, I find that hard to accept. But it is true we can go for weeks without enough rain to really wet the ground — except last August, when we all braced for the much-heralded drought, only to receive twice as much rain as usual (2.32 inches rather than the normal 1.14 inches).

Our gardens ground us in our natural environment and give us a sense of place, but only if we understand and acknowledge what that place really offers us as gardeners. Find your own reality check with the thorough and readable "The Natural History of Puget Sound Country" by Art Kruckeberg ( University of Washington Press, 1991) and the literate exploration of our weather, "Rains All The Time" by David Laskin (Sasquatch Books, 1997).

Valerie Easton is a horticultural librarian who writes about plants and gardens for Pacific Northwest magazine. She is the co-author of "Artists in Their Gardens" (Sasquatch Books). Her e-mail address is

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