When to Plant Lavender

Spring planting

The standard window is spring, after your last frost; the dates for your zone above show when that falls. UC IPM gives the same rule for California, transplant in spring after the last frost, and Iowa State recommends spring planting once the risk of severe frost has passed.

Spring plantings have one advantage: a full growing season to build roots before their first winter. Colorado State notes that because of that long season, spring transplants can be smaller than fall ones. Water new plants regularly through the first summer, even though established lavender is drought tolerant.

Spring is the better choice where winter is the main threat. In Iowa and the Upper Midwest, Iowa State says winter survival is the greatest challenge, with wet soils and repeated freeze-thaw cycles doing the damage. A plant that has had all summer to root into a well-drained bed is much better equipped for that than one planted in October.

Fall planting

Where winters are milder or drier, fall is often the better season. Colorado State cites research at New Mexico State’s Alcalde science center showing that fall-planted lavender survives better, establishes more quickly and produces more flowers the following season than spring-planted lavender.

Two conditions make fall planting work. First, plant size: Colorado State specifies plants in 4-inch or larger pots with an established root system, which it says is needed to ensure survival over winter. Second, timing: plant early enough for roots to grow out into the soil before cold weather. No extension source gives a fixed number of weeks before frost, so earlier in fall is safer, particularly in zones 5 and 6.

In dry-winter regions, Colorado State adds that winter watering increases survival of fall plantings, and that the root zone should not dry out completely over winter. Fabric row covers can protect new plants from wind and heavy snow.

Timing by region

California

UC IPM publishes planting windows for each part of the state, noting they are approximate:

• North and North Coast (Monterey County north): April-May or September-November
• South Coast (San Luis Obispo County south): April-May or September
• Interior valleys (Sacramento and San Joaquin): April or October
• Desert valleys (Imperial and Coachella): March or September

Humid South and Florida

In hot, humid regions, plant in fall so lavender establishes during the cool, drier months before summer humidity sets in. The UF/IFAS Osceola County herb calendar lists September-October for Central Florida and treats lavender as an annual there, and UF/IFAS Gardening Solutions includes it among herbs to plant in fall. Choose Spanish lavender, French lavender (L. dentata), ‘Phenomenal’ or ‘Goodwin Creek Grey’, which UF/IFAS Pasco County recommends for Central Florida.

Mountain West and dry interior

Colorado State notes lavender can be planted from spring through fall there. Fall planting with larger plants, plus winter watering, gives the best results.

Cold north

Plant English lavender or a hardy lavandin in spring after frost, in a raised bed or berm. If you want to try a tender type such as Spanish lavender, plant it in spring as an annual or in a container you can bring in for winter.

Starting from cuttings or seed

Timing cuttings is simple: Colorado State recommends taking them right after plants bloom, and they root in about 3 weeks. Pot them up into 2- to 4-inch pots and plant out once the root system is strong. In practice, summer cuttings become plants for fall planting in mild areas, or for the following spring in cold ones.

Seed takes much longer to reach planting size. Iowa State recommends chilling seed in a moist medium at 40°F for 2 to 4 weeks, then sowing on the surface of seed-starting mix at 65 to 70°F, where germination often takes 2 to 4 weeks or more. Seedlings grow slowly, need bright light and must be hardened off before going outside after frost.