Some herbs do well in summer heat

Richard Bogren, Gill, Daniel J.  |  5/11/2018 1:36:16 PM

By Dan Gill

LSU AgCenter Horticulturist

(05/11/18) To be honest, our best herb gardens occur during milder times of the year between October and May. The intense heat of summer takes its toll on many of our favorite culinary herbs, such as thyme, parsley, dill, cilantro, chives, lavender and French tarragon. But herb gardens should be looking great now, and some heat-loving herbs can be planted for summer production.

Herbs that like milder weather should be at their most productive now. These herbs are best planted in the fall or late winter, and by now they should have produced large, productive plants. Because production will drop as the weather gets hotter, feel free to harvest generously now. You might even want to preserve some of these herbs by drying or freezing for use during the summer.

Flavor saver

When drying herbs, harvest the stems long enough to easily tie them together. Next, rinse with water and blot dry. Make small bundles of about three to five stems held together with rubber bands, and insert an unbent paper clip or S-shaped piece of wire to make a hook. Hang the bundles in a cool, dry place with good air circulation — like a spare bedroom with the ceiling fan left on.

Another way to dry herbs is to lay leaves or short sprigs on a cookie sheet lined with paper towels. Place them in a cool, dry location with good air circulation. Avoid using a warm oven or microwave because the heat will cause the loss of volatile, flavorful oils.

When the herbs are thoroughly dry, store them in tightly sealed containers labeled with the name of the herb or herb blend and the date. You can leave the leaves whole or crumble them to the desired fineness.

To freeze herbs, harvest, rinse and blot dry. Remove leaves from woody stems and chop them finely before freezing. Place chopped herbs in a freezer bag, spreading them out in a half-inch layer. This makes it easier to break off usable pieces later on when the herbs are frozen solid. Force out as much air as possible, seal and freeze. Be sure to label the bag with the name of the herb because chopped frozen herbs tend to look the same.

Summer herbs

Basil (Ocimum basilicum) is the most popular summer herb. It thrives during our hot, humid summers and asks for nothing more in the garden than full to part sun and average garden soil that drains well. Water during dry weather, and keep beds mulched to conserve soil moisture and control weeds. Basil grows quickly from seed, which may be planted now through July. Transplants, which are readily available at area nurseries, may be planted in the garden through August.

Allow newly planted basil transplants to grow for a while before you start to harvest. For standard-size varieties, you can generally start to lightly harvest when the plants reach about 1 foot tall. Individual basil leaves may be harvested for use, but more typically the plant is pinched or cut back. Cut or pinch basil just above a pair of leaves removing no more than a third to a half of the plant at one time. This leaves plenty of foliage to keep the plant healthy and productive.

When harvested regularly, basil is more bushy and attractive in the garden. Harvesting and using fresh basil for seasoning is wonderful because the full, rich flavors are at their peak when used fresh. When basil blooms, the young flower spikes can be chopped and used just like the leaves. And flower stalks with open flowers also make nice garnishes.

Another of my favorite summer herbs is Mexican or Spanish tarragon (Tagetes lucida). Native to Mexico, this marigold relative produces large, bushy plants 2 to 3 feet tall by the end of summer. The foliage is rich with the flavor of tarragon and is an excellent substitute for French tarragon, which languishes in summer heat. In late summer and fall, this care-free plant bursts into bloom with masses of golden yellow marigold flowers. It is a hardy perennial that goes dormant in winter but returns reliably each spring.

Perilla (Perilla frutescens) is an annual Asian herb with a unique flavor. The form I grow has dark purple, ruffled leaves similar to coleus or purple basil. I use it freely in flower gardens as well as with the herbs. Although an annual, perilla self-seeds freely, and it is common to see new seedlings appear in the spring where it has grown previously.

Sweet Annie (Artemisia annua) is a traditional Chinese medicinal herb that I grow for its wonderfully fragrant foliage. The aroma is rich, sharp and clean and is retained for an amazingly long time after the foliage is cut and dried. This is a great aromatic herb for crafts like potpourris, sachets and wreaths. Start seeds of this warm-season annual herb in April or May each year.

You would not think of sesame seeds as a traditional American flavoring, but how many times have you seen a generous sprinkling of sesame seeds on the bun of an all-American hamburger? I’ve grown sesame (Sesamum indicum) a few times, and it is easy and rewarding. Plant seeds when the weather is warm. The plants will bloom and produce seed pods right along the stems. When the seed pods begin to mature, cut the plant off at ground level (or branches if it’s too big) and place it upside down in a paper bag. The seeds will fall down to the bottom of the bag.

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Basil is a popular herb that thrives during hot, humid Louisiana summers. Photo by Rick Bogren/LSU AgCenter

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In late summer and fall, Mexican tarragon bursts into bloom with masses of golden yellow marigold flowers. Photo by Dan Gill/LSU AgCenter

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