Lavender, known for its calming fragrance and silvery foliage, originates from the arid, sunny landscapes of the Mediterranean. Successfully cultivating this herb in Pennsylvania presents a unique challenge, given the state’s humid summers and often harsh, wet winters. Gardeners in the region, which spans USDA Hardiness Zones 5 through 7, must carefully consider both the timing of planting and the preparation of the site.
Optimal Planting Seasons in Pennsylvania
The optimal window for planting lavender in Pennsylvania is generally in the late spring or early summer. Planting should occur after the danger of the last hard frost has completely passed, which typically falls between late April and early May, depending on the specific hardiness zone within the state. This timing allows the young plants to establish a robust root system during the temperate conditions of late spring and benefit from the full growing season.
A secondary, less preferred planting window exists in the late summer or early fall. If planting during this period, it is important to ensure the plant has at least eight to ten weeks of moderate weather before the first heavy frost is expected. Spring planting remains the generally recommended approach in Pennsylvania, as it maximizes the time available for establishment before the plant faces the challenges of its first winter.
Site Selection and Soil Preparation
Lavender thrives when exposed to full sunlight, requiring a minimum of six hours of direct sun exposure each day for optimal growth and oil production. Proper drainage is perhaps the single most important factor for success, as the plant’s roots are highly susceptible to rot in consistently saturated conditions. Pennsylvania’s native soil is often clay-heavy, which naturally impedes water flow and must be substantially amended before planting.
To improve drainage, gardeners should incorporate coarse materials such as horticultural sand, fine gravel, or small quantities of well-aged compost into the planting bed. Lavender prefers a slightly alkaline soil environment, with a target pH range of 6.7 to 7.3. Gardeners can raise the pH of acidic Pennsylvania soil by mixing in a small amount of dolomitic lime or wood ash during the preparation phase.
Selecting Hardy Lavender Varieties
Success with lavender in Pennsylvania relies heavily on selecting varieties known for their cold tolerance. English lavender, botanically known as Lavandula angustifolia, is the best choice for this region, as it is generally hardy down to USDA Zone 5. Cultivars like ‘Munstead’ and ‘Hidcote’ are highly recommended because they reliably survive the cold winter temperatures common throughout the state.
Other popular types, such as French lavender (Lavandula dentata) or Spanish lavender (Lavandula stoechas), are significantly less cold-tolerant. These less hardy varieties often struggle to survive a typical Pennsylvania winter and usually require intense protection or must be treated as annuals.
Ensuring Winter Survival
Before winter sets in, only a very light pruning should be performed, primarily to remove spent flower spikes. Heavy pruning in the fall can stimulate new, tender growth that will not harden off in time, making the plant more vulnerable to frost damage.
Applying a protective layer of material around the plant’s base helps to regulate soil temperature and prevent root heave. A layer of coarse material, such as pea gravel or small wood chips, should be loosely applied to protect the root crown from the alternating freezing and thawing action. It is important to avoid heavy, moisture-retaining organic mulches, as these can trap moisture against the crown and increase the risk of fungal disease and root rot during the dormant season.