Q: My 6-year-old lavender plants are woody and falling apart. What have I done wrong? Should I plant some other variety? — Jean W., San Luis Obispo
A: Local gardeners love lavenders; they’re hardy, sweet-smelling plants resistant to insect pests and deer. Lavender can live up to 20 years, but plants often get woody after six to eight years. Heavy soil and regular summer watering are primary reasons for this problem.
To encourage longer life, let plants dry out in summer before watering. If you have clay soil, plant on a slope and/or amend soil in the planting area. Lavenders prefer light, rocky soils and require little fertilization.
Overfertilizing is another reason plants quickly grow woody and break open. Fertilize them lightly the first year you plant them; they probably will not need further nutrients.
Regular pruning improves the looks of lavenders and prevents them from breaking apart. Start when plants are young, as it’s hard to get back to a nice, rounded shape if pruning is neglected. Prune after bloom or as you cut flowers in the summer. Cut off about one-third of the green growth at this time, and shape up the outer edges of bushes to keep them rounded. If you didn’t cut back after blooms faded, you can prune into fall (but not too late in the year in hard-frost areas). Try regenerating a woody plant by pruning the remaining green down almost to the wood and hope for new growth. Dry wood on lavenders will not resprout, according to experts.
As for varieties to plant, choices are many. Most nurseries sell fast-growing, sturdy hybrid lavenders (Lavandin) such as Grosso and Provence, reputed to resist heat and fun gus disease better than the English lavenders (Lavandula angustifola).
For drying, the English lavenders that come in several named varieties retain color well. French (Lavandula dentata) or the early-blooming, fuschia-colored Spanish (Lavandula stoechas) can be lightly cut after their first bloom to encourage summer re-bloom. Newer lavenders also come in white, pink and yellow, as well as blues and purple.
GOT A GARDENING QUESTION?
Contact the UC Cooperative Extension Master Gardeners: at 781-5939 from 1 to 5 p.m. Monday and Thursday; at 473-7190 from 10 a.m. to noon Wednesday in Arroyo Grande; and at 434-4105 from 9 a.m. to noon Wednesday in Templeton. Visit the UCCE Master Gardeners Web site at http://ucanr.org/sites/mgslo or email firstname.lastname@example.org .