This morning was our first hard frost of the year: the first time Matt had to bust out the scraper for the truck’s windows, and the first time the grass was silver and not just crunchy when I went out to feed the chickens.
When we had our first little frost I brought the tarragon inside. I do this every year without success, but maybe this time it’ll pull through. I give it plenty of water and light indoors, but I think the problem is shock. I think I am supposed to be bringing it inside in stages, the same way seedlings need to be moved out in stages. Sort of a reverse hardening-off.
Rosemary is supposed to be one of those herbs you cannot kill. Oh yeah? Well look at me go. I’m on my fifth or sixth rosemary this year. I know it gets colder here than in the rest of our zone because we are in a vicious little microclimate (stuck between a mountain and a series of lakes). If something is budding out or blooming in town – just five miles away – it won’t bud or bloom here for another week. Down in the lowlands, where Matt works and we do the majority of our shopping, the climate is yet another week ahead of town.
The facts state that rosemary should be fine on its own without coddling during the kinds of winter temperatures we get. (Our coldest winter temperature in the time we’ve lived here was in the teens. It does not normally drop below the twenties.) Anecdotally, however, the consensus is that it is the freeze-thaw cycle, not simply cold itself, that dooms rosemary in the Pacific Northwest.
So this year I’m going to pretend I’m gardening in Alaska, rather than Washington, and I’m going to bundle up my Rosemary like the little brother from A Christmas Story. While I’m at it, I’m going to do my new little lavender, too. I used to have lavender in the front yard but they got progressively more leggy and leafless at the base until they were so ugly I pulled them out. This, too, can be caused by winter damage, so I’ll do to the lavender what I’m doing to the rosemary.
Rosemary, lemon verbena, and a few other perennial herbs are not reliably winter hardy. Extra winter protection can be provided by cutting plants back to within a couple inches of the ground after the first hard frost and covering the remaining stub with soil. Then cover the soil with a 4- to 5-inch layer of mulch.
The reason I’ve waited so long to do this is also explained in the Extension bulletin: “Heavy mulching before cold weather occurs should be avoided since it will keep the soil warmer and may actually decrease winter hardiness.”
I’ll let you know whether or not I was successful come spring!