Lavender in Zone 8B — Pacific Northwest

Lavender is a fantastic addition to any Pacific Northwest garden. Its fragrant blooms and silvery foliage thrive in our mild summers and cool nights, adding beauty and versatility. Use it in cooking, crafts, or simply enjoy its calming scent as you stroll through your garden on a crisp evening.

While we don't have the intense heat of other regions, our 210-day growing season gives Lavender plenty of time to flourish with the right approach. Getting the timing right and understanding our specific climate challenges will set you up for success.

Starting Lavender from seed indoors is possible, but it can be slow and a bit tricky. If you're up for a challenge, begin in early to late February, about 10 weeks before you plan to transplant outdoors. Use seed trays with good drainage, a heat mat to keep the soil around 70°F, and grow lights to provide consistent light, especially during our overcast spring days.

Bottom watering is really helpful for seedlings to avoid disturbing the delicate new growth and prevent damping off. Honestly, though, for reliable results, you might consider buying starts from a local nursery.

Transplant your Lavender seedlings outdoors from mid April through early May, once the soil has warmed up a bit. Before planting, harden them off by gradually exposing them to outdoor conditions for about a week. Choose a sunny spot with well-drained soil and space the plants 12-18 inches apart.

Keep an eye on the weather forecast; we can still get some chilly nights and unexpected rain in late spring. If a cold snap is coming, be prepared to cover your young plants. Lavender really prefers drier soil, so don't rush things if we're having a particularly wet spring.

Lavender is very drought-tolerant, thriving in the dry conditions of our mild summers. Overwatering is a far bigger problem here than underwatering. During our wet springs, you might not need to water at all after transplanting, unless we have an unusually dry spell.

Once the dry summer months arrive, check the soil before watering. Stick your finger about 2 inches deep; if it's dry, then it's time to water. Usually, about an inch of water per week is plenty during the hottest part of the summer, but even that might be too much if we're getting regular rainfall. Water at the base of the plant to avoid getting the foliage wet, which can encourage fungal diseases in our sometimes humid conditions.

Signs of underwatering include wilting or drooping leaves, while yellowing leaves can indicate overwatering. A light mulch of gravel can help improve drainage and keep the base of the plant dry.

Prune your Lavender after it finishes flowering, usually in late summer. Deadhead the spent flowers and lightly shape the plant into a neat mound. Cut back the stems by about one-third, but be careful not to cut into the old wood, as it won't regrow.

In late fall, after the first frost around early November, you can give the plant a light tidy-up, removing any dead or damaged stems. Avoid heavy pruning at this time of year, as it can make the plant more vulnerable to winter damage.

You can expect your first Lavender harvest from mid July through late August, 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 good color but haven't fully opened yet.

Cut the stems as long as possible, leaving several inches of foliage on the plant to encourage new growth. Bundle the stems together and hang them upside down in a cool, dark, well-ventilated place to dry. Regular harvesting encourages continued blooming, so keep cutting those flowers throughout the summer. Even as we approach our first frost in early November, you can still snip off any remaining blooms to enjoy indoors.

Here are some common problems you might encounter with Lavender in the Pacific Northwest:

Root rot from overwatering

• What it looks like: Yellowing leaves, wilting, stunted growth, and a general decline in plant health. Roots may appear brown and mushy.
• What causes it: Overwatering, especially in heavy, poorly drained soil. Our wet springs can exacerbate this issue.
• How to fix/prevent it: Ensure excellent drainage by planting in raised beds or amending the soil with gravel or sand. Water sparingly, especially during the rainy season.

Shab disease

• What it looks like: Brown or black spots on the leaves and stems. The plant may appear stunted and the flowers may be discolored.
• What causes it: A fungal infection that thrives in humid conditions.
• How to fix/prevent it: Improve air circulation by spacing plants adequately and pruning to remove crowded growth. Avoid overhead watering. Remove and destroy infected plant material.

Phytophthora

• What it looks like: Sudden wilting and dieback of branches, often starting at the tips. The bark at the base of the plant may be discolored and the roots may be rotted.
• What causes it: A soilborne pathogen that attacks the roots, especially in wet conditions.
• How to fix/prevent it: Ensure excellent drainage and avoid overwatering. Improve soil health by adding organic matter. Remove and destroy infected plants.

Pacific Northwest Specific Challenges: While Lavender loves our mild summers, our dry-summer humidity can be a challenge. Ensuring good air circulation and avoiding overwatering are crucial for preventing fungal diseases.

Lavender makes a great companion plant for several herbs and flowers in our region. Rosemary, thyme, and sage all share similar growing requirements—full sun and well-drained soil—and can help deter pests. Roses also benefit from being planted near Lavender, as it can help repel aphids.

Avoid planting Lavender near mint, as mint's aggressive growth can quickly crowd out Lavender and steal valuable nutrients. Mint also prefers more moisture than Lavender, creating an unfavorable environment for the latter.