French Lavender: A Guide to Growing and Caring for It in Your Garden

French lavender, scientifically known as Lavandula dentata, is a stunning flowering plant prized for its soothing fragrance and delicate purple flowers. Native to the Mediterranean, these plants are a beloved choice in gardens worldwide. The calming aroma of French lavender is often used in essential oils and perfumes. While the name 'French lavender' sometimes refers to another variety, Lavandula stoechas, it typically refers to Lavandula dentata in the U.S.

French lavender is distinct from other lavender varieties with its serrated, scalloped leaves and gray-green color. This unique texture sets it apart from its counterparts. French lavender thrives in sunny, dry environments and can tolerate some neglect, making it a hardy choice for gardens. However, there are a few essential care tips to follow for successful growth. Here's how to cultivate and care for French lavender in your yard.

Ideal Growing Conditions

French lavender thrives in sunny, dry environments with alkaline soil. These plants require well-draining soil and abundant sunlight. In warmer regions, the soft purple flowers bloom year-round, while in cooler areas, they typically appear from spring through fall. 

“Lavender prefers the sunniest, hottest corner of your garden,” says horticulturist and landscape designer Nathan Heinrich. “It doesn’t need shade, though it can handle morning shade as long as it gets full sun in the afternoon.”

“With proper care, annual pruning, ample sunlight, and minimal watering, lavender plants can live for 15 years or more,” Heinrich adds. French lavender is a resilient plant that can thrive for years in sun-soaked, dry settings.

Soil and Fertilizer Needs

When planting French lavender, opt for neutral or alkaline soil that is low in nutrients. These plants don't thrive in nutrient-rich soil, so there’s no need to fertilize. If your soil lacks proper drainage, you can add a layer of gravel mulch on top to improve it.

It's best to plant your French lavender in spring, once the threat of frost has passed but before the summer heat arrives. If you live in a region with mild winters, you can also plant it in the fall. 

Watering

Since French lavender prefers dry conditions, you only need to water newly planted lavender once every few weeks until it begins to bloom. Be cautious of overwatering, as root rot is the biggest threat to this plant. Make sure to plant it in dry, well-draining soil. 

“Avoid overwatering during the summer months,” advises garden designer Michele Chambliss, an ASHS-certified horticulturist. “In areas with heavy rainfall, planting on a raised berm with gravel mulch can aid drainage. Lavender roots that sit in warm, damp soil are susceptible to rot.”

Once your French lavender plants are established and in full bloom, watering becomes unnecessary unless you’re dealing with extreme heat or drought conditions.

Pruning Recommendations

“Lavender plants, regardless of variety, can generally be left alone once a year for pruning and will continue to bloom and thrive for many years,” says Heinrich. French lavender needs annual pruning to maintain its best appearance. In colder climates with harsh winters, prune in early spring. For warmer regions with blooms year-round, prune in late summer or early fall. 

“In mild climates, French lavender may bloom throughout the year,” explains Heinrich. “This can make determining the right pruning time tricky. However, the ideal period is from mid-August to early September, once the summer growing season ends and the weather begins to cool.”

Heinrich suggests cutting your lavender back to around knee height or to the point where the stems transition from gray-green to brown and dead-looking. If your plant has healthy growth all the way down to the roots with no dead stems, cut the plant back to half of its current size. Avoid cutting too drastically, as French lavender doesn’t regenerate from old wood. 

Common Pests and Plant Diseases

French lavender is a resilient plant that resists many pests. However, excessive watering and humid conditions can cause root rot. Water sparingly, especially after planting or during extreme heat and drought. If the leaves start to wilt, droop, or turn yellow, reduce watering and let the soil dry out. 

In humid climates or with wet soil, French lavender may be prone to powdery mildew. To prevent this, ensure the soil drains well and avoid overwatering. If you notice a white or grayish dust on the leaves, treat it with organic fungicide or neem oil to get rid of the mildew. 

“French lavender can sometimes attract aphids in the spring,” says Chambliss. “These can be washed off with a strong jet of water, and soon enough, beneficial insects will take care of them. I believe it's worth the extra effort to create the ideal environment for enjoying the fragrance and beauty of French lavender in our gardens.”