Lavender in Zone 3B — Midwest

Lavender is absolutely worth the effort in our Midwest gardens. The fragrance alone is intoxicating, and you can use it in everything from cooking to crafts. Plus, the satisfaction of growing something so beautiful that also thrives in our fertile soil is hard to beat.

Sure, Midwest weather can be unpredictable, but lavender is tougher than you think. With a little attention to timing, and understanding our 118-day growing season, you can absolutely enjoy thriving lavender plants.

Starting lavender from seed indoors is possible, but honestly, it can be a bit finicky. It's really only worth it if you're after a specific variety that's hard to find as a transplant. If you want to give it a shot, start your seeds indoors from mid-March through early April, about 10 weeks before you plan to transplant.

Use seed trays with a good seed-starting mix, and keep them consistently warm. Bottom watering is helpful to avoid disturbing the tiny seeds. Remember, our springs can be a bit late, so don't rush things.

The easiest way to get good results with lavender here in the Midwest is to buy established starter plants. Transplant them outdoors in early June, once you're confident the danger of frost has passed.

Before planting, harden off your lavender starts by gradually exposing them to outdoor conditions for about a week. Space them about 12-18 inches apart in a sunny spot. Keep an eye on the weather; even in early June, we can sometimes get a late cold snap.

Here in the Midwest, overwatering is a much bigger threat to lavender than underwatering. Remember, lavender is drought-tolerant and thrives in drier conditions. Our wet-summer rainfall and moderate-to-humid climate mean you need to be extra careful.

During our moderate-to-hot summer heat spells, water deeply but infrequently. Use the finger test: stick your finger about two inches into the soil. If it's dry, water. Aim for about an inch of water per week, but only if rainfall hasn't provided it. Always water at the base of the plant to avoid getting the foliage wet, which can encourage fungal diseases in our humid climate.

Signs of underwatering include wilting leaves and stunted growth. Overwatering, on the other hand, can lead to yellowing leaves and root rot. Mulch around the base of the plants with gravel to improve drainage and prevent the soil from staying too wet.

Pruning is important for keeping your lavender plants healthy and productive. After flowering, deadhead the spent blooms and lightly shape the plant into a mound. Cut back by about one-third, but be careful not to cut into the old wood, as it won't regrow.

Prune in late summer, after the main flush of blooms is finished. As the first frost approaches around mid- September, stop pruning to allow the plant to harden off for winter.

You can expect your first lavender harvest in early to late September in our Midwest climate. Look for flower stems where the buds are showing good color but haven't fully opened yet. Cut the stems long in the morning, after the dew has dried.

To harvest, simply cut the stems with sharp scissors or pruning shears. For continued production, keep deadheading spent flowers throughout the season. As the first frost approaches in mid- September, harvest any remaining flowers to dry and enjoy indoors. Hang the harvested stems upside down in small bundles in a cool, dark, and dry place to dry.

Here in the Midwest, lavender can sometimes face a few challenges:

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: Overwatering, especially in our clay soil that doesn't drain well. Our wet-summer rainfall can also contribute.
• How to fix/prevent it: Ensure excellent drainage by amending the soil with plenty of gravel. Water sparingly, only when the top few inches of soil are dry. Consider planting in raised beds or containers.

Shab Disease

• What it looks like: Brown or black spots on the leaves and stems, followed by wilting and dieback.
• What causes it: A fungal disease that thrives in humid conditions.
• How to fix/prevent it: Provide good air circulation around the plants by spacing them properly. Avoid overhead watering. Remove and destroy any infected plant material.

Phytophthora

• What it looks like: Sudden wilting and death of the plant, often accompanied by dark lesions on the stems near the base.
• What causes it: A soilborne pathogen that thrives in wet conditions.
• How to fix/prevent it: Ensure good drainage. Avoid overwatering. If you suspect Phytophthora, remove and destroy the infected plant and the surrounding soil.

Midwest Specific Challenges: Our moderate-to-hot heat and moderate-to-humid humidity, combined with our wet-summer rainfall, create a perfect environment for fungal diseases and root rot. Good drainage and careful watering are essential for success.

Lavender makes a great companion to several herbs and flowers in the Midwest garden. Rosemary, thyme, and sage all enjoy similar growing conditions – full sun and well-drained soil – and can help deter pests. Roses also benefit from being planted near lavender, as lavender can help repel aphids.

Avoid planting lavender near mint. Mint spreads aggressively and can quickly take over, crowding out your lavender. Plus, mint prefers moist soil, which is the opposite of what lavender needs to thrive.