Richard Bogren, Gill, Daniel J.
For Release On Or After 04/18/14
By Dan Gill
LSU AgCenter Horticulturist
Many Louisiana gardeners have discovered how easy and rewarding growing herbs can be. Especially popular are the culinary herbs used to flavor foods. The trend for gardeners to plant and grow herbs continues to gain in popularity. Indeed, planting herbs is fairly common these days, particularly among gardeners like me who enjoy cooking.
The term “herb” is used botanically to refer to any non-woody plant. Horticulturists and gardeners today generally use the word herbaceous instead, as in “herbaceous perennial” meaning a non-woody, perennial plant.
In common usage, the word herb refers 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 uses. In culinary circles, however, herbs are considered to be the green, leafy parts of plants – either fresh or dried – while spices are seeds, barks, flowers, berries or roots. 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 despite careful culture. When selecting which herbs you want to grow in your garden, consider what you commonly cook with. Look at the herbs in your kitchen cabinet, and start off growing those types of herbs first.
Be very careful if you decide to grow and use medicinal herbs. Used improperly, some medicinal herbs can be quite toxic.
Most herbs require excellent drainage and direct sun at least four to six hours a day. 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 using a commercial potting soil.
Locate your culinary herb-growing area as close to the kitchen as possible, so the herbs are convenient to use while you are cooking. If you have to walk all the way across the yard to harvest them, they will likely be underused, allowing the plants to 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. You can plant transplants now, but we are late in the cool season at this point. You may, however, 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 afternoon summer shade. Even 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. They are generally best planted in fall.
Several perennial herbs cannot tolerate our summers and are grown here as cool-season annuals, including 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, being careful not to deplete all of the plant’s foliage. Generally, take no more than one-third of the total foliage at any one time. When harvested regularly, herbs are more uniform and compact in size, which makes them more desirable as garden plants. Harvesting and using herbs fresh is best for seasoning because the full, rich flavors are at their peak. The flowers of most herbs may also be used as a garnish or to flavor dishes.
Sometimes the herb garden can be too productive. At these times it is 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). Ways to preserve them for longer periods are drying and freezing.