Lavender in Zone 6A — Pacific Northwest

Lavender is worth growing here in the Pacific Northwest for its fragrance, versatility, and the simple joy of having a piece of Provence in your own backyard. The cool nights and mild summers we experience enhance the essential oil production, giving you intensely fragrant blooms. Plus, it's a beautiful addition to any garden.

Growing lavender in our Zone 6A climate has its challenges. We have cool, wet springs. But, by timing your planting right and choosing the right spot, you can definitely succeed. Our 148-day growing season gives you ample time to get a good harvest.

Starting lavender from seed indoors is possible, but honestly, it's a bit finicky. It's slow to germinate and grow, so many gardeners opt for starts from a local nursery. If you're up for the challenge, start your seeds indoors from early to late March, about 10 weeks before you plan to transplant them outside.

Use seed trays with a well-draining seed starting mix. Lavender needs warmth to germinate, so a heat mat can be helpful. Once seedlings emerge, provide plenty of light – a grow light is ideal, especially given our overcast spring days. Water from the bottom to avoid damping off.

Transplant your lavender outdoors from late May through mid-June, after the last expected frost. Before planting, harden off your seedlings by gradually exposing them to outdoor conditions for about a week. This helps them adjust to the sun and wind.

Space your lavender plants 12-18 inches apart to allow for good air circulation. Choose a sunny spot with well-drained soil. Honestly, buying starts from a reputable nursery is the most reliable way to get a thriving lavender plant here in the PNW.

Lavender thrives on neglect, especially here in the dry summer months of the Pacific Northwest. It's very drought-tolerant and prefers poor, dry soil. Overwatering is the biggest threat to lavender.

During the wet springs, you likely won't need to water at all. Once the dry summer months arrive, check the soil with the finger test. Stick your finger about 2 inches deep into the soil near the base of the plant. If it feels dry, it's time to water. Give it a good soak, aiming for about an inch of water per week, but let the soil dry out completely between waterings. Water at the base of the plant to avoid getting the foliage wet, which can encourage fungal diseases in our region.

Signs of underwatering include wilting or drooping leaves. Overwatering can cause yellowing leaves and root rot. A light mulch of gravel can help improve drainage and keep the soil dry around the base of the plant.

Pruning is important for keeping your lavender plant healthy and productive. After the flowers fade, usually in late summer, deadhead the spent blooms by cutting the stems back to just above a leaf node. This encourages new growth and more blooms.

Shape the plant into a neat mound, cutting back about one-third of the overall growth. Be careful not to cut into old wood, as lavender doesn't typically regrow from there. As the first frost approaches in early October, stop pruning to allow the plant to harden off for winter.

You can expect your first lavender harvest from late August through early October, about 90 days after transplanting. The best time to harvest is in the morning, after the dew has dried but before the sun gets too hot. Look for flower stems where the buds are showing color but not fully open.

Cut the stems as long as possible, leaving several inches of foliage on the plant. Gather the stems into small bundles and tie them together with twine. Hang the bundles upside down in a cool, dark, and dry place to dry. This preserves the fragrance and color of the flowers.

Continue to harvest throughout the blooming season to encourage more flower production. As the first frost approaches, harvest any remaining flower stems to dry and use in crafts or potpourri.

Lavender is generally low-maintenance, but here are a few common problems to watch out for in the Pacific Northwest:

Root rot from overwatering

• What it looks like: Yellowing leaves, wilting, and stunted growth. The roots may be brown and mushy.
• What causes it: Soggy soil and poor drainage, often exacerbated by our wet springs and tendency to overwater.
• How to fix/prevent it: Plant in well-drained soil. Avoid overwatering, especially during rainy periods. Amend heavy clay soils with compost or gravel to improve drainage.

Shab disease

• What it looks like: Stunted growth, distorted leaves, and a general decline in the plant's health.
• What causes it: A fungal disease that thrives in humid conditions.
• How to fix/prevent it: Provide good air circulation by spacing plants properly. Avoid overhead watering. Remove and destroy infected plants.

Phytophthora

• What it looks like: Sudden wilting and death of the plant. The roots may be dark and decayed.
• What causes it: A soilborne pathogen that spreads quickly in wet conditions.
• How to fix/prevent it: Ensure excellent soil drainage. Avoid planting lavender in areas prone to standing water. Use disease-free plants.

Pacific Northwest Specific Challenges: Our mild heat and dry summer rainfall generally benefit lavender, but our cool springs and occasional late blight outbreaks can pose challenges. Be vigilant about drainage, and avoid overwatering, especially during the cooler months.

Lavender makes a great companion plant for several other herbs and flowers in the Pacific Northwest garden. Rosemary, thyme, and sage all thrive in similar dry, sunny conditions. They help to repel pests and attract beneficial insects. Roses also make good companions, as lavender can help deter aphids.

Avoid planting lavender near mint. Mint is aggressive and can quickly spread and crowd out lavender. It also prefers moister soil conditions, which are not ideal for lavender.