By: Joseph Masabni, Ann Wheeler and Mengmeng Gu
Herbs are an ancient category of the plant world. Found almost everywhere, herbs have been defined generally as “the useful plants.” Besides adding beauty, herbs are used for cooking, making scents and perfumes, practicing aromatherapy, herbal healing in folklore and in modern medicine, and attracting bees and butterflies to the garden.
Because many herbs hybridize readily, new varieties are produced every year. Varieties are created for specific markets or needs, such as for patio gardens, container gardens, dry climates, or areas with salty water or soils.
Herbs can also play a role in landscaping: Does the location need tall plants, shade-tolerant plants, ground covers? Different herbs can meet a variety of needs.
The following are simple principles to help you choose an herb for your garden:
Your herbs need not be used for cooking; in fact, many herbs are not culinary at all.
- Many herbs, such as basil, are fragrant when brushed against. Consider planting them near a path or doorway.
- Match the herb’s sunlight requirements with sites that meet those needs.
- Many herbs attract beneficial insects such as bees and ladybugs. Examples are anise hyssop, borage, comfrey, fennel, and yarrow. Pineapple sage attracts butterflies and hummingbirds.
- Herbs also repel less-desirable visitors: Rosemary (cabbage moths, carrot flies, and bean beetles), chives (aphids, mites), sage (flea beetles), and mint (aphids, cabbage moths, flea beetles). The aromatic properties of some herbs (rosemary, Russian sage, bee balm) are even reported to fend off hungry deer.
- Anecdotal evidence tells us that pairings of specific herbs with specific plants benefit the plants; for example, rue planted near roses produces a root chemical that repels Japanese beetle grubs, which feed on the roses’ roots. Basil planted near tomatoes deters flies and mosquitos. Catnip deters ants, flea beetles, and weevils. Hyssop planted near cabbage, cauliflower, or broccoli deters cabbage moths.
- Think texture—herbs are champions in this area!
Herbs for specific landscaping needs
Herbs can be used for low hedges and borders, as backgrounds, to fill empty spaces between other plants, in sunny or shady areas, and for their flowers, flavor, or scent. When choosing a spot to plant, keep in mind the herb’s eventual size and shape. Remember that herbs in their 4-inch pots look a lot alike and don’t reflect their final mature size.
Low hedges and borders
Herbs work well to define the edge line of a garden or to soften the edges. To choose edging plants that will work with your garden’s sun exposure, cross-reference those below with the list of herbs for shady areas.
Options for hedges and borders:
- Artemisia (Artemisia sp.), especially the smaller varieties like southernwood
- Chives (Allium schoenoprasum)
- Germander (Teucrium sp.)
- Lamb’s ears (Stachys byzantina)
- Parsley (Petroselinum crispum), curled or Italian
- Rosemary, prostrate (Rosmarinus officinalis)
- Santolina (Santolina sp.), gray and green varieties
- Thyme (Thymus sp.)
- Winter savory (Satureja montana)
Backgrounds and empty spaces
Taller herbs can grow in the very back of a garden, and others can fill spaces between specimen plants like roses. When determining placement, consider the plant’s eventual width as well as its height. Following are some options for herbs of differing heights and widths
- African blue basil (Ocimum sp.), very tall
- Bay (Laurus nobilis), a tall, aromatic, evergreen tree or large bush
- Lemongrass (Cymbopogon citratus), very tall
- Artemisia (Artemisia sp.), most are wide
- ‘Aussie Sweet’ basil (Ocimum sp.), tall and narrow
- Fennel (Foeniculum vulgare), bronze and green varieties
- Dill (Anethum graveolens), various heights
- Mexican bush sage (Salvia leucantha), wide
- Pineapple sage (Salvia elegans), wide
Low and wide
- Rose geranium (Pelargonium graveolens), low and wide
Many herbs produce attractive flowers, which lure bees, butterflies, and hummingbirds. Some options are:
- Basil (Ocimum)
- Bergamot (Citrus bergamia)
- Borage (Borago officinalis)
- Feverfew (Tanacetum parthenium)
- Foxglove (Digitalia purpurea)
- Germander (Teucrium chamaedrys)
- Oregano (Origanum vulgare)
- Rosemary (Rosmarinus officinalis)
- Salvias (Salvia sp.)
- Yarrow (Achillea millefolium)
Most herbs require a sunny exposure; gardeners with considerable shade in their garden often despair or fail at growing them. However, even sun lovers appreciate afternoon shade in the Texas summertime, and some, like parsley, accept partial shade.
Beyond those general guidelines, each herb has a range of light requirements specific to that plant.Beginning gardeners should plant herbs in a container and move it around the garden to try various locations until you find the ideal spot. Try a container for this exercise, but not a tiny container.
A variety of herbs can tolerate shade, many of which also make an effective ground cover
Lovage (Levisticum officinale) grows best during cool weather. It is best grown as an annual in Texas because of the hot summers.
Lemon thyme (Thymus vulgaris) is an ideal peren- nial for part sun. The plants may decline in August because of the excessive heat in Texas.
Marjoram (Origanum majorana) is an evergreen perennial.
Oregano (Origanum vulgare) is an evergreen perennial with nice blooms.
Roman chamomile (Chamaemelum nobile) is suited for partial sun. Shade will prolong its life in the summer. It is a cool-season annual.
Rosemary (Rosmarinus officinalis) is an evergreen perennial; some cultivars have nice blooms.
Catnip (Nepeta cataria) is a year-round evergreen perennial.
Patchouli (Pogostemon cablin) is a very tender perennial and may not survive the winter.
Deep shade to bright sun
Comfrey (Symphytum officinale), a perennial, may go dormant in the heat of summer.
Garlic chive (Allium tuberosum) is an evergreen perennial with pretty blooms.
Lemon balm (Melissa officinalis) is an evergreen perennial and excellent as ground cover.
Mints, including pennyroyal, are evergreen but will go dormant in midsummer. Cut them back in the summer for fall regrowth.
Bright sun to part shade
Parsleys (Petroselinum crispum) are biennial plants that often behave like annuals in Texas, going to seed during first year. They grow well in cool weather.
Bright sun to deep shade
Chervil (Anthriscus cerefolium), an annual, has dense, frilly leaves with excellent flavor.
Cuban oregano (Plectranthus amboinicus) has thick, succulent-type leaves. The plants are easily rooted and grow best in warm/hot seasons.
Valerian (Valeriana officinalis) can tolerate sun or shade. It is an evergreen perennial with white, vanilla- scented blooms.
Success in growing herbs begins with the soil. Keeping the soil healthy is the primary work of a gardener. Try to think about how to improve your soil every day, or at least every season before planting, and then take steps to improve and maintain it.
A neutral pH is fine. However, herbs must have good drainage. If the subsoil doesn’t drain well, build raised beds so that the roots don’t sit in water.
A good method of planting is to avoid plowing up the soil; this technique is called no-till planting. But 18 inches of soil depth, however it is achieved, is a requirement.
Add amendments into the soil every year. Amendments help maintain the desired soil depth, fertility, microorganism health, and tilth (the space between particles that makes air and water circulation possible).
One excellent amendment is compost, whether homemade or commercial. Easy-to-use compost cages that sit on the ground provide air and water circulation. When the compost is ready, just lift up the cage and use the compost. To quote gardening author and radio and TV host Felder Rushing, “Stop throwing that stuff away. Pile it up somewhere.”
Think of a compost pile as working decorative art in the garden. If you have chickens or a cow, goat, horse, or sheep, add a trash bag amount of manure to the compost pile from time to time. It will speed up the composting and make your place smell nice and rural.
Mulch conserves moisture and keeps the soil cooler during the horrendous Texas summer temperatures and unrelenting sun. Organic mulches improve soil health as they break down and become another form of compost. Leaves and pine needles can be used as mulch; however, deep layers of large oak leaves may keep rain from soaking well into the soil, and they take forever to decompose.
Mulching advice that is specific to herbs: Don’t pile it up around 4-inch herbs; most small herb plants need good air circulation, or their stems will begin to rot. Pull back the mulch a bit when you plant lavender, rosemary, sage, and thyme especially. For these Mediterranean natives, a layer of gravel around them can improve drainage and reduce stem rot
Water annual herbs as you do other annuals; for example, treat basil as you do other heat-lovers.Lavender, rosemary, sage, and thyme grow best if the leaves stay mostly dry. Water them at ground level (almost essential with lavender; the others are a bit more flexible).
Gravel not only allows water to drain quickly away from the foliage, but it also reflects heat up into the plant’s dense center to help dry any wet leaves.Fatal to these particular herbs is the lingering moisture that encourages fungal diseases. Do not use lawn sprinklers where herbs are growing.
Contrary to urban gardening myths, herbs do need to be fertilized. Mix a balanced, slow-release organic fertilizer into the soil at planting, and then sprinkle it over the soil every 3 to 6 months.
However, do not over fertilize herbs—it produces lavish growth but diminished flavor, especially in culinary herbs. For example, too much fertilizer encourages mints to flower, which reduces leaf production and flavor. And no one wants lanky lavender or rosemary.
Another way to improve plant growth is to add mycorrhizal amendments, which are naturally occurring fungi that help healthy roots form.
Pruning and shaping
The best way to keep herbs in shape is to use them. However, it can be hard to keep up with some fast-growing herbs such as basil in summer. Cutting off blooms will save more energy for the leaves.
The key is to prune gently and often to avoid excessive leaf drop that produces bare, woody stems. Pruning woody lavender, rosemary, sage, or thyme nearly always kills the plant.
Basil (annual): Choose among the 64 species according to mature height, leaf type (smooth or curly, small or large), leaf and flower color, and desired scent/flavor, such as sweet, citrus, or spicy.
Lavender (perennial): Lavender is difficult to grow in our climate. The best varieties for Texas conditions are fernleaf (L. multifida), French (L. dentata), Goodwin Creek Gray (L. lavandula x hybrida), Provence (L. lavandula × intermedia), Spanish (L. stoechas), and sweet (L. heterophylla) oregano.
Mint (hardy perennial): Mint has two basic oils, peppermint and spearmint, so choose among the more than 2,000 varieties and 19 species according to your preferences for scent or flavor. Only M. mentha × gracilis varieties such as ‘Doublemint Madalene Hill’or ‘Redstem Applemint’ have both oils. Pineapple mint, a variegated variety (M. suaveolens), can take some shade.
Oregano (hardy perennial): Varieties are available with different flavors, flowers, scents, leaf appearances, and growth habits (creeping and mounding).
Rosemary (hardy perennial): Choose a variety suited to your needs—such as upright or prostrate (mounding) growth habit and preferred use. Upright varieties are preferred for culinary purposes. ‘Blue Lady’, a prostrate variety, blooms profusely.
Sage (perennial): The 900 species worldwide differ in leaf coloration and growth habit. Most have the same scent and flavor (except S. clevelandii, which is recommended for scent, not flavor.)Sage may not survive a hard freeze. The best variety for Texas is ‘Newe Ya’ar’ sage.
Thyme (hardy perennial): The 350 species and many hybrids offer choices in growth habit (creeping, mounding, upright), leaf and flower color, and preferred scent or flavor.Thyme plants form mats of roots, but their low fertility requirements make them good for under- planting. Thyme resists drought but must have good drainage.
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