GREEN PATCH

Enlarge Image Image Gallery Along with shaping the plant, shearing serves a second purpose: you can save the trimmings and dry them. Illustration by Gayle Ford

Question: My southernwood looks sort of weedy—about waist high, with a dozen or so skinny stems. What happened? Did I buy the wrong plant?

Answer:Sometimes plant labels get misplaced in display gardens or nursery sales areas, but that’s probably not what happened here. Southernwood is a ball-shaped plant about 18 inches tall and with gray-green foliage. Check your plant’s leaves. If they’re fine-textured, divided into slender segments, feel soft and silky, and have an appealing lemon-pine-camphor aroma, your plant is probably southernwood (Artemisia abrotanum).

I’d guess the main reason your plant looks so different from what you expected is that you haven’t been pruning it. More than many other herbs, southernwood’s appearance depends on how you treat it. Unpruned plants grow tall and loose, as yours has, whereas plants that are pruned repeatedly become dense and compact. Southernwood likes plenty of sun, so if your plant is in shade for part or most of the day, that would make it more open than usual, perhaps even straggly. Plants also tend to get bushier with age.

Start pruning your southernwood next spring, when daffodils and forsythia are in bloom. First, shake the plant and run your fingers through its stems to comb out the old leaves and litter (southernwood hangs onto its foliage at least partway through the winter, even in cold climates). Next, use sharp pruning shears to cut off all the stems, leaving stubs 6 to 9 inches tall. Remove about one-third of the remaining stubs by cutting them off close to the ground; include the oldest stems (those with weathered bark) as well as the thinnest, weakest ones. Discard the trimmings, rake any debris out from under and around the plant, apply a balanced fertilizer using the dosage recommended on the label, and ­refresh the mulch. Within a few weeks, new shoots will sprout from buds all along the stems.

As soon as the new shoots are about 6 inches long, shear off 2 to 3 inches of the new growth. Otherwise, the stems will grow straight and tall as your plant did this year. Trimming the tips makes the stems branch and keeps the plant short and bushy. You can use pruning shears for this job, but it’s easier and faster to use sharp hedge shears. Trim the entire surface into the round shape you desire.