Lavender in Zone 3B — Great Plains

Lavender is a worthwhile addition to any Great Plains garden. Its fragrance is wonderful, it's versatile in the kitchen and for crafts, and its drought tolerance makes it a good fit for our variable rainfall. Plus, the intense sunshine here helps lavender develop its best color and aroma.

Our extreme weather can be tough, but with careful timing, you can absolutely grow lavender here. The 118-day growing season requires a little planning, but it's doable. We'll focus on getting your plants off to a strong start so they're ready to thrive.

Starting lavender from seed indoors is possible, but honestly, it's a slow process. Unless you're a very patient gardener, buying starts from a local nursery is the way to go. If you're determined to start from seed, begin in mid-March through early April, about 10 weeks before you plan to transplant.

Use seed trays with a good seed-starting mix. Keep the soil consistently moist (bottom watering is a great way to avoid disturbing the tiny seeds) and provide plenty of light. A heat mat can also help with germination. Remember, spring here is variable, so be prepared for temperature swings that might affect germination.

Transplant your lavender outdoors in early June, once the risk of frost has passed. Before transplanting, harden off your seedlings by gradually exposing them to outdoor conditions for about a week. This helps them adjust to the sun and wind.

Plant lavender 12-18 inches apart in a sunny spot with well-drained soil. Our prairie soil is usually fertile enough, but be sure the location doesn't stay soggy after a rain. Even in June, we can get hail, so consider a temporary cover if severe weather is predicted right after transplanting. For reliable results, buy starts rather than trying to grow from seed.

Lavender thrives on neglect when it comes to water, especially here on the Plains. It's very drought-tolerant and actually prefers poor, dry soil. Overwatering and high humidity are its biggest enemies, so excellent drainage is essential.

During the growing season, water deeply only when the top 2 inches of soil are dry. Use the "finger test" to check. In a typical Plains summer with hot heat and variable rainfall, you might only need to water established plants once a week, or even less. Aim for about 1 inch of water per week if rainfall is scarce. Water at the base of the plant to avoid wetting the foliage, which can encourage disease in our low-to-moderate humidity.

Signs of underwatering include wilting and drooping leaves. Overwatering symptoms are yellowing leaves and soft, mushy stems. A light mulch of gravel can help retain some moisture while preventing the soil from staying too wet.

Pruning lavender is essential for maintaining its shape and encouraging new growth. The key is to deadhead spent flowers and shape the plant into a nice mound.

After flowering, usually in late summer, prune back the stems by about one-third. Be careful not to cut into the old, woody growth, as it won't regrow. As the first frost approaches around mid- September, stop pruning to allow the plant to harden off for winter.

Expect your first lavender harvest in early to late September, about 90 days after transplanting. The best time to harvest is in the morning when the buds are colored but not fully open. This is when the essential oils are most concentrated.

Cut the long stems, leaving enough foliage on the plant for continued growth. Bundle the stems together and hang them upside down in a cool, dark, and dry place to dry. Lavender doesn't ripen off the vine, so timing is important. You can harvest continuously as more flowers bloom. As the first frost approaches in mid- September, harvest any remaining buds to dry indoors.

Lavender is relatively low-maintenance, but here are three common problems to watch out for:

Root Rot from Overwatering

• What it looks like: Yellowing leaves, wilting, and a general decline in plant health. The roots will be brown and mushy.
• What causes it: Soil that stays too wet, usually from overwatering or poor drainage. This is especially problematic during periods of heavy rainfall.
• How to fix/prevent it: Ensure your lavender is planted in well-draining soil. Water only when the top 2 inches of soil are dry. Avoid overwatering, especially during wet periods. Consider raised beds or amending the soil with sand to improve drainage.

Shab Disease

• What it looks like: Stunted growth, yellowing leaves, and eventual death of the plant. It often starts with small, dark spots on the stems.
• What causes it: A fungal disease that thrives in humid conditions. While our humidity is generally low-to-moderate, prolonged wet spells can create favorable conditions.
• How to fix/prevent it: Provide good air circulation around your plants. Avoid overhead watering. Remove and destroy any infected plant material. Fungicides may be necessary in severe cases.

Phytophthora

• What it looks like: Sudden wilting, yellowing of leaves, and dark lesions on the stems near the soil line. The roots will be dark and decayed.
• What causes it: A soilborne pathogen that thrives in wet conditions. Poor drainage and overwatering contribute to its spread.
• How to fix/prevent it: Improve soil drainage by amending with compost or planting in raised beds. Avoid overwatering. Remove and destroy infected plants. Phytophthora can persist in the soil, so avoid planting lavender in the same spot for several years.

Great Plains Specific Challenges: Our hot heat, low-to-moderate humidity, and variable rainfall mean that drainage is absolutely critical for lavender. While the heat can stress the plants, the biggest risk is from periods of heavy rain followed by intense sun, which can create the perfect conditions for root rot and fungal diseases. Monitor your plants closely, especially during periods of extreme weather, and adjust your watering accordingly.

Lavender benefits from companions that share its love of sun and well-drained soil. Rosemary, thyme, and sage are excellent choices because they attract beneficial insects and don't compete for water. Roses also make good companions, as they appreciate similar growing conditions and their contrasting colors create a beautiful display. Avoid planting lavender near mint, as mint is a water hog and will quickly outcompete lavender for resources.