It’s official — we are now in the U.S. Department of Agriculture’s “hardiness Zone 8B.”

Are we really? Twenty-five years ago, when I was studying landscape design, my professor said something I’ll always remember: “People think we have mild weather here in the Pacific Northwest, but every four to six years we get walloped by Mother Nature.”

I’ve been observing the weather ever since, and he was right. Since 1990, we’ve had 10 different years where the temperature dropped below the 20-degree mark, the high end of Zone 8B. But the story isn’t just low temperature. It’s also duration of the cold snap. Many 8B plants can handle a day or two of below 15 to 20 degrees, but when we get a cold snap that exceeds three days, our precious plants start dying.

The bottom line? If you like the tropical look or have a favorite plant that’s a little on the zonal edge, go for it. Just plan on the possibility of occasionally replacing it or having to whack it down to the ground in hopes that it comes back.

I adore New Zealand Flax. It is said to be Zone 8. I’ve grown them for a few years, and then they get frozen out. Some are hardier than others, but it’s still risky. I continue to put them in designs, but I warn the client that it’s a great plant and well worth replanting when it gets struck down.

If you are more interested in having a low maintenance, easy-care garden, use Zone 8 plants sparingly and stay completely away from Zone 9 — unless you like hauling big pots into your garage. I gave that up years ago, along with hauling benches in for the winter. I know there is a temptation to test how far you can go, but remember those who go where others fear to tread just might get their plants frozen.

Ann Nickerson has lived and

practiced landscape design in the Tualatin Valley since 1993. You can contact her at or by phone at 503-846-1352 with your comments or questions.

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