Class preview: Herbs from the Garden

Learn about tansy and other herbs
in Duke Gardens' Herbs from the Garden class

By Crystal Cotton

A thriving herb garden that produces sugar, spice and everything nice needs some basic planning and care. Horticulturist Jan Watson has some sage advice for beginners, as well as those seeking to expand their herb palette.

The dirt

The best way to have prosperous herbs is by cultivating rich soil, says Jan Watson, a horticulturist at Duke Gardens.

“Work your soil up a little bit, get some nice soil in there, and the herbs will reward you a hundred-fold,” says Watson.

Tilling your soil or adding compost to it will help your herbs tremendously.

What to plant?

“The herbs that are the best are the ones that you find uses for,” says Watson. You may want herbs because of their scent, their taste or even for dyes. But you can also get creative with garden design by picking shapes, colors and textures that go together interestingly.

“You can use tansy, and a specific kind called Tanacetum ‘Isla Gold’ would be gorgeous,” says Watson. “Allium fistulosum, fennel and dill would be awesome. Fennel and dill have a really furry texture. If you mix that with the Allium fistulosum, which is very rigid and onion-like, it’d be a good combination because the textures are so different.”

When to plant & water?

Most people plant their herbs in early spring. But it’s not too late to plant them now, Watson says.

“June is a perfect time to plant,” she says. “You’ve just got to remember to water because they’re not established yet. So even though they’ll be drought-tolerant later, when you first put them in, you obviously have to water them.”

But avoid over-watering, she notes, particularly with rosemary and lavender, which are sensitive to too much water.

Sun or shade?

Most herbs want full sun, though some prefer a little bit of shade.
“Parsleys, basils, cilantro, dill—that’s all going to want some afternoon shade,” says Watson. “Otherwise, it’s going to ‘bolt’—it goes to seed too fast.”

When and how much to cut?

Try to avoid over-cutting, Watson says. And if they’re perennial herbs, don’t cut them back too late in the season. A good rule of thumb is to never cut off more than a third of an herb at a time, and only a little bit more as winter approaches. Cutting them too severely before winter will expose the stems to cold temperatures and may cause dieback.

Think outside of the pot

If you want to grow something different, try Stevia rebaudiana, which has become popular as a sugar substitute. You can add it most recipes that would otherwise call for sugar. But use less, because it’s more concentrated.

You can also try Cryptotaenia japonica, commonly known as Japanese parsley. This is a great substitute for regular flat-leaf parsley and it can be used in any dish that normally calls for parsley, such as soup and spaghetti. Since it’s a little stronger than flat-leaf parsley, you don’t have to use as much.

If you’re more interested in benefiting wildlife, fennel –which comes in black or the traditional green—would be a perfect herb to plant.

“It attracts swallowtail caterpillars. They eat the foliage and they actually lay their eggs on it. So there’s a benefit right there,” says Watson. “Right now in my fennel at home, there are baby praying mantises hiding amongst the foliage of the fennel. So for the wildlife aspect, it’s just so beneficial to the insects.”

Don’t like bugs? Why not plant one fennel for the caterpillars and one for yourself? The same with parsley. And remember, caterpillars become butterflies. So if you like butterflies, this is a way to bring more of them into your garden.

Herbal inspiration

For more ideas about what to plant, you can always visit Duke Gardens. There are several herbs growing at the bottom of the Terraces on the café side, and even in the Perennial Border that leads from the Rose Garden to the pergola. These include flat-leaf parsley, curly leaf parsley, Japanese parsley, chives, fennel, dill, marjoram, oregano, thyme and many others.

If you’d like to learn more, consider taking Watson’s class “Herbs from the Garden” on June 17 from 2 to 4 p.m. For information, call Duke Gardens’ registrar at 919-668-1707, email slsmith@duke.edu or go to gardens.duke.edu to read more.

Sarah P. Duke Gardens creates and nurtures an environment in the heart of Duke University for learning, inspiration and enjoyment through excellence in horticulture. The Gardens is at 420 Anderson St.

Crystal Cotton is a junior at N.C. Central University and a communications intern at Duke Gardens.