by Judy Kautz, OSU Extension Master Gardener
Lavender (Lavendula spp.) is a well-known and fragrant perennial plant with gray-green foliage, upright flower spikes, and a compact shrub form. It's native to Europe and can be planted in the spring after the risk of frost has passed and the soil has warmed up. It will grow at a moderate pace, often adding a few inches to its size each year.
In the garden, lavender makes an excellent companion plant for almost anything from roses to cabbage. It is one of those aromatic, gray herbs that deer avoid, making it a great choice as a decoy in your beds. Lavender can be toxic to pets like dogs and cats.
Lavender makes an excellent companion plant for almost anything, and it is one of those aromatic, gray herbs that deer avoid.
As with most plants, your success in growing lavender will depend both on what kind of growing conditions you provide and which varieties you select to grow. Lavender plants will tolerate many growing conditions, but they thrive best in warm, well-draining soil and full sun.
Most lavenders are labeled hardy in USDA zones 5a through 9a, but this is not a plant that is dependable enough to use as a hedge. Realistically, you can expect plants to do well when the weather cooperates, but be prepared to experience the occasional loss of a plant or two after a severe winter or a wet, humid summer.
Even if you do everything right and your lavender plants appear happy, the genus is generally not long-lived and most lavender plants begin to decline in 10 years or less. Keep starting new plants to ensure you have a bountiful harvest for years to come. Lavender plants are fairly trouble-free, but leaf spots and root rot can occur if the soil is too wet. Additionally, many plants will perish if their soil gets too wet over the winter months.
Lavender plants thrive in full sunlight, which is the best way to guarantee a lot of buds and big, full bushes. They don't tolerate much (if any) shade, so don't plant them in a spot where they'll be overshadowed by trees or other large plants.
Lean soil will encourage a higher concentration of oils (and good smells), so go easy on the organic matter and fertilizer. Lavender plants prefer well-drained soil that is on the drier side, so if you're using a traditional potting mix, be sure to add in some sand for drainage. An alkaline or especially chalky soil will enhance your lavender's fragrance, while any pH below about 6.5 will likely cause lavender plants to be very short-lived.
Lavender is a resilient plant that is extremely drought-tolerant once established. When first starting your lavender plants, keep them regularly watered during their first growing season. After that, they can handle extended periods of drought—in fact, too much water can lead to fungal disease and root rot.
Lavender can withstand a range of temperatures, and it's usually dampness more than the cold that's responsible for killing lavender plants. Dampness can come in the form of wet roots during the winter months or high humidity in the summer. If humidity is a problem, make sure you have plenty of space between your plants for airflow, and always plant your bushes in a sunny location. Protect lavender plants from harsh winter winds by planting them next to a stone or brick wall to provide additional heat and protection. If you live in an area where the ground routinely freezes and thaws throughout the winter, your lavender plants will benefit from a layer of mulch applied after the ground initially freezes to protect the roots.
It's a good idea to add a handful of compost into the hole when you are first starting lavender plants. Beyond that, feeding is not needed with these plants and can detract from the overall potency of your lavender.
Although lavender plants get regularly pruned simply by harvesting the flowers, a bit of spring pruning is recommended to keep your plant well-shaped and to encourage new growth. Taller lavender varieties can be cut back by approximately one-third of their height, while lower growing varieties can either be pruned back by a couple of inches or cut down to new growth.
If your lavender suffers winter die-back, don't prune your plants until you see new green growth at the base of the plant. If you disturb the plants too soon in the season, they're unlikely to develop new growth.
A major reason lavender is so prized is that its flowers keep their fragrance once dried. For best drying results, harvest the flowers as the buds first begin to open. Hang them in small bunches upside-down in a warm spot with good air circulation until dried. Besides being beautiful and aromatic, lavender flowers are also edible. They can be used raw in salads, added to soups and stews, used as a seasoning, baked into cookies, and brewed into tea. Use sparingly; a little lavender flavor goes a long way.
For best drying results, harvest the flowers as the buds first begin to open. Hang them in small bunches upside-down in a warm spot with good air circulation until dried.
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