Yes there are clay soils in Western North Carolina, and humidity, and sometimes a lot of rain. Does that mean you can’t grow lavender? Honestly, WNC is not an ideal climate for lavender, but with the right preparation and care, yes, you can grow lavender here. Follow these growing tips for success with lavender and share some of your own expert advice in the comments below.
Plenty of Sunlight
Lavender needs six plus hours or direct sunlight a day. The best way to think of it is parking lot sun—completely unobstructed, no trees around, sunlight. 10 a.m. to 4 p.m. full sun. The emphasis is strong because shade is the predominant theme in WNC landscapes, and homeowners try to push the sunlight to shade ratio for plants. A little bit of sunlight is often translated as just enough sunlight for a full-sun plant. Save yourself the frustration and be honest about your sunlight situation. Remember lavender does great in containers if your deck is full sun and your landscape is shady.
Prep the Soil
Lavender, like most herbs, doesn’t want fussy soil. Lavender does best in lean, well-drained soils. The soil should be easy to dig in, loose, and not compacted. How to create that when most soils in WNC are heavy, rocky, clay soils?
Plant in raised beds, raised mounds, on banks, and in containers.
When planting in heavy, cake-like soils, add permatill or pea-sized gravel to the soil. Add up to a 50/50 mix of permatill and native soil, depending on the drainage of your soil. Lavender needs well-drained, but not arid soils.
Mix 1/2 cup of Daddy Pete’s Soil Conditioner, great for busting up clay soils and loosening soils, to the mix or use as mulch. (Go ahead and buy the big bag—2 CF—and use the remaining product in your perennial beds as a topdress or for plantings.)
The pH is best at 6.5-7.5. Add lime if necessary to neutralize the pH of the soil.
The goal is to improve the drainage of the soil, not give lavender a nutrient-rich soil. Fertilize lightly when growing lavender, once a year with a complete fertilizer.
To test your drainage:
Dig a hole 12” in diameter and 12” deep with straight edges.
Fill the hole with water, and let sit overnight. Saturating the soil before testing gives a more accurate drainage result.
After 24 hours refill the hole with water.
Measure drainage every hour. Lay a stick across the hole and use a measuring tape to determine the water level. Note the number of inches per hour the water drained.
Good drainage is considered around 2” per hour for plants with average drainage needs. If it less than 1” per hour the drainage rate is too slow and plants have wet feet, over 4” per hour the rate is too fast and plants become parched.
Pick the Right Varieties
Pick cultivars that are hardy to our area and are proven to be more disease resistant. Lavender is zone 5-8. At B.B.Barns we have many lavender varieties to choose from. Ask staff for help determining which ones are best suited for your site. Brian Jennings, our annuals buyer, has three favorites: ‘Phenomenal,’ ‘Provence’ and ‘Platinum Blonde.’ (In that order.)
Planting Deep and Wide
Dig holes at least 12”-18” deep and 4’-6’ apart. Lavender roots extend deep and wide (up to a 12” down and 6’ feet wide). Giving plants space between them allows for better air circulation and room to grow. Lavender grows quickly.
Lavender is drought tolerant after it’s established. When establishing it, water deeply and regularly every 5-7 days for the first month and then every 7-10 days for the remaining first season if rain doesn’t reach an inch a week in the garden. After establishing, lavender can handle dry spells and extreme heat.
Lavender needs annual pruning. When deadheading, also prune and shape, leaving 1”-2” of foliage, removing dead stems along the bottom of plant. In spring, shape lightly if needed. Lavender is a woody plant that can become heavy as it ages, exposing the center of the plant and causing the main stem to split, which kills the plant. Pruning annually will help keep that in check.
Cinthia Milner, garden coach and blog writer.
B.B.Barns Garden Center serves all of Western North Carolina, upstate South Carolina and Tennessee.