Herbs like lavender thrive in warm locations with well-drained soil, making them a great choice for many climates in Texas. Since Texas covers a range of growing regions in U.S. Department of Agriculture Plant hardiness zones 6 through 9, make sure you select a lavender species that grows well in your area.
There are 28 different species of lavender, and numerous cultivars. Different lavender species have similar growing requirements, but they are not equally well-suited to all areas of Texas. Before planting lavender, check the growing requirements for different species to find the right fit for your area.
English Lavender (Lavandula angustifolia, USDA zones 5 through 8). In the summer, this species produces lavender-blue or dark blue-purple flowers that hold their color when dried. The plants grow 1 to 3 feet tall depending on the cultivar. English lavender is more cold-hardy than other species, and grows well in northern and central Texas. It is not hardy along the Gulf Coast.
Spanish Lavender (Lavandula stoechas, USDA zones 8 through 9). This species blooms earlier in the summer than English lavender. The flowers are pine-cone shaped, purple and dry well for use in potpourri. Plants grow 1 to 3 feet tall. Spanish Lavender is a good fit for hot, humid summers found in eastern and southern Texas.
French Lavender (Lavandula dentata candicans, USDA zones 5 through 9). This species thrives in hot weather, but is also hardy throughout all of Texas. It grows 2 to 3 feet tall, with an attractive mounding shape common among lavenders. This variety of French lavender has larger leaves than other lavenders, and blooms purple in the spring.
Choose a Location
Lavenders love warm locations in full sun, and will not grow well even in partial shade. Choose open areas for planting, or locate lavenders near a wall that gets plenty of sunlight. In northern and western parts of the state where the weather can be cooler, planting lavenders near a sunny wall or the side of a house helps keep them warm. Walls provide shelter from wind, and absorb heat during the day to help warm plants at night.
With their tidy, compact shape, lavenders are a popular choice for borders and hedges in flower and herb gardens. Just make sure surrounding plants won't grow tall enough to shade the lavenders too much. Since lavenders require well-drained soil, they are also a good choice for rock-garden landscapes.
Find Well-Drained Soil
All lavender species require very well-drained soil. Moderately fertile soil that drains quickly, with a soil pH of 6.5 to 7.5, is ideal. In soils that are poorly drained, you can plant lavender in mounds to help water drain away from the root crown. Alternately, in very poor and compacted soil, you can increase drainage by amending the soil.
Compacted, heavy clay soils require drastic amendments before lavender will grow. To amend this type of soil, you'll need to add enough coarse sand or fine gravel to replace up to 75 percent of the native soil and incorporate it to a depth of 18 to 36 inches. This usually involves digging-up the garden soil, mixing in the amendments and then replacing the soil.
In soils that are less compacted but need a bit more drainage, you can use organic amendments like peat moss or well-composted manure. If you amend with organic matter, do not fertilize at planting time. When adding organic amendments to sandy loam, use enough that the resulting soil is 25 percent organic matter. When amending clay soils, use at least 50 percent organic matter. Incorporate organic amendments to a depth of 18 inches.
Plant Just Right
In hot climates, lavender does best when planted in the early fall. If you live in an area of Texas with cooler winters, such as north Texas USDA zones 6 and 7, plant lavender in mid-spring so it has a chance to establish a deep root system over the summer months.
Space most lavender plants 24 inches apart -- or as indicated on the plant tag. Lavender needs good air circulation to prevent leaf diseases, so avoid crowding them. Dig a hole slightly wider than the pot. This loosens soil around the plant so it's easier for new roots to grow. In soils that don't drain well, remember to mound-up soil and plant lavender slightly higher than the surrounding soil surface.
Water With Care
For the first year after planting, keep the soil moist to encourage deep root growth. It is best to supply enough water to soak the soil deeply and then wait a few days between watering, rather than applying smaller amounts of water more frequently. Use a drip-irrigation system, or spot-water near the base of the plant. Overhead watering promotes disease.
Once established, lavenders are drought-resistant. They require very little supplemental water, though regular irrigation to keep the soil moist but not soggy before blooming encourages good flower development. When they are not blooming, water only if the plants show signs of drought-stress like drooping leaves.
Excessive nutrients cause lavender plants to break apart in the center and produce weak growth, so be careful not to over-fertilize. In soils with very low fertility that have not been amended with organic matter, work a balanced fertilizer with an N-P-K ratio of 10-10-10 into the soil at a rate of 1/2 to 1 pound per 100 square feet before planting.
Fertilize established lavenders once a year in the early spring, before flower buds start to develop. Side-dressing with compost is often enough; this simply involves spreading a 1-inch-thick layer of compost around the base of the plant and working it into the top 3 to 6 inches of soil. Alternately, you can apply a general-purpose fertilizer. Use a slow-release formula with a low N-P-K ratio, such as 12-4-8, and apply at a rate of 4 tablespoons per 4 square feet.