Get It Growing News For 04/11/08
By Dan Gill
LSU AgCenter Horticulturist
Interest in growing herbs has been rising over the years as Louisiana gardeners increasingly have planted herbs in herb gardens or containers or in beds among existing plants. Especially popular are the culinary herbs used to flavor food. This trend continues today as strong as ever. Indeed, planting herbs is no longer a novelty but more of a standard practice, particularly among gardeners like me who enjoy cooking.
The term “herb” is used botanically to refer to any nonwoody plant. Horticulturists and gardeners generally use the word herbaceous instead, as in “herbaceous perennial,” meaning a nonwoody, perennial plant. In common usage we use the word herb to refer to any plant – herbaceous or woody – whose leaves, flowers, seeds, wood, roots, bark or other parts are used for flavorings, fragrance, medicines, cosmetics, pest control, dyes or other things. Despite common disagreements on pronunciation, it is equally appropriate to pronounce the “h” or leave it silent.
Louisiana gardeners can successfully grow a wide variety of herbs, although some, such as French tarragon and English lavender, often succumb to our hot, wet summers in spite of careful culture. When selecting which herbs to grow in your garden, consider what you commonly use for cooking. Look at the herbs in your kitchen cabinet and start off growing those first.
Be very careful if you decide to grow and use medicinal herbs, however. Used improperly, some medicinal herbs can be quite toxic.
Most herbs require direct sun at least 4 to 6 hours a day and excellent drainage. In Louisiana, raised beds are often best for most herbs because of our generous annual rainfall. If raised garden beds are not practical for you and your drainage is poor, try growing herbs in containers with a commercial potting soil.
Place your culinary herb-growing area as close to the kitchen as possible, so the herbs are convenient to use when you’re cooking. If you have to walk all the way across the yard to harvest them, they will likely be underused and become overgrown and wasted.
For growing purposes in Louisiana, herbs can be loosely grouped into cool-season annuals, warm-season annuals and perennials. Annuals live for one season and then die, while perennials live for several years. Cool-season herbs can tolerate normal winter freezes and should be seeded or transplanted September through February. Planting transplants now can be done, but we are late in the cool season at this point. You may still get acceptable harvests in May or early June if you plant parsley, cilantro or coriander, dill, fennel and borage now.
Terrific warm-season annual herbs are basil (in all its myriad forms and flavors), sesame and perilla. They can be seeded in pots now and transplanted into the garden as soon as they are big enough. Purchased transplants could also be planted this month and through the summer.
Some of the perennial herbs that do well here are mints, lemon verbena, lemon balm, rosemary, Mexican tarragon, sorrel, society garlic, garlic chives, oregano, monarda, catmint, anise hyssop, mountain mint, French bay, pineapple sage and rue. All of the perennial herbs can be planted now using transplants available at local nurseries.
Thyme, sage, catnip, lavender and many of the scented geraniums are perennial herbs that require excellent drainage to survive the summer. They may be more successful when grown in containers and placed in a location that gets some shade in the afternoon during the summer. Even when they’re grown under good conditions, they tend to be short-lived and often succumb to root and stem rots in the hot, wet, late-summer season.
Several perennial herbs that cannot tolerate our summers and are grown here as cool season annuals include French tarragon, feverfew and chamomile. If you don’t have them planted in your garden yet, transplants of these should definitely be planted immediately, but harvest will likely be limited.
Herbs should be harvested frequently and regularly. But when you harvest, be careful not to deplete a plant’s foliage. Generally, take no more than one-third of the total foliage at any time. When harvested regularly, herbs are more uniform and compact in size, which makes them more desirable as garden plants. Herbs that are harvested and used fresh are best for seasoning because the full, rich flavors are at their peak. The flowers of most herbs also may be used as garnish or to flavor dishes, too.
Sometimes the herb garden can be too productive. At these times, it’s important to know how to preserve the extras. Most herbs can be kept for a few days after harvesting with their stems placed in containers of water, or for a week or two in plastic bags in the vegetable storage section of your refrigerator – but not basil. You can preserve herbs for longer periods by drying and freezing them.
Get It Growing is a weekly feature on home lawn and garden topics prepared by experts in the LSU AgCenter. For more information on such topics, contact your parish LSU AgCenter Extension office or visit our Web site at www.lsuagcenter.com. A wide range of publications and a variety of other resources are available.
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Contact: Dan Gill at (225) 578-2222 or dgill@agcenter.lsu.edu
Editor: Rick Bogren at (225) 578-2263 or rbogren@agcenter.lsu.edu