Lavender, with its fragrant foliage and purple blooms, is a perennial herb native to the Mediterranean region. A perennial lives for more than two years, returning season after season. For a plant originating in a mild climate, surviving the harsh, prolonged winters of the Upper Midwest is challenging. However, with careful selection of varieties and specific protective measures, this herb can be cultivated successfully as a perennial in a Minnesota garden. Long-term survival requires understanding the state’s unique climate and tailoring gardening practices to overcome the extreme cold.
Understanding Minnesota’s USDA Hardiness Zones
The United States Department of Agriculture (USDA) Plant Hardiness Zone Map is the primary tool gardeners use to determine which plants can survive winter in a specific location. This system divides the country into zones based on the average annual extreme minimum winter temperature. Minnesota’s climate spans several zones due to its size and geographic position.
The state ranges from the extremely cold Zone 3 in the northern third to Zone 4 across the majority of the central and southern regions. The Twin Cities metro area and parts of the southeast have recently been updated to Zone 5a, reflecting slightly warmer minimum temperatures. Most common lavender varieties are rated for Zone 5 survival, tolerating lows down to -20 degrees Fahrenheit. This rating creates a survival barrier for gardeners in the colder Zone 3 and Zone 4 areas, making careful variety selection and winter preparation essential for success.
Recommended Cold-Hardy Lavender Varieties
To grow lavender as a perennial in Minnesota’s challenging climate, selecting cultivars with proven cold tolerance is necessary. The most successful varieties belong to the English Lavender species, Lavandula angustifolia, known for their resilience and strong fragrance. These English types offer the highest degree of winter hardiness, making them the best candidates for perennial growth in Zone 4 and protected Zone 3 locations.
One consistently recommended cultivar is ‘Munstead,’ which is hardy down to USDA Zone 4. This compact variety typically grows 12 to 18 inches tall, producing abundant lavender-blue flowers. Another hardy L. angustifolia cultivar is ‘Hidcote,’ recognized for its deep purple blooms and upright growth, usually reaching 12 to 24 inches. Both ‘Munstead’ and ‘Hidcote’ can often survive in Zone 3 when provided with reliable snow cover or additional winter protection.
Gardeners may also consider the hybrid ‘Phenomenal,’ a Lavandula x intermedia cross. This variety combines the cold tolerance of English lavender with the heat tolerance of Portuguese lavender. ‘Phenomenal’ is notable for its exceptional vigor, featuring silver foliage and long flower spikes that often reach 24 to 34 inches. It is reliably hardy to Zone 4 and valued for its robust resistance to environmental stresses.
Essential Winter Protection Strategies
Even the hardiest lavender varieties require specific care to endure a Minnesota winter, especially the harsh cycles of freezing and thawing. The single most important factor for winter survival is ensuring the plant is established in soil that drains exceptionally well. Lavender is highly susceptible to root rot, which is often caused by cold, soggy soil during the dormant season. To improve drainage, planting on a slight mound or amending the soil with grit or gravel is often helpful.
Strategic placement is another factor that improves winter hardiness. Planting lavender near a south-facing wall or structure provides a microclimate that offers a slight temperature increase and protection from harsh northwest winds. Gardeners must stop fertilizing the plants by late summer to allow the new growth to harden off before the first frost. Pruning should also be avoided in the fall, as the stems and foliage help to insulate the woody base of the plant through the winter.
The final step for winterizing is applying a thick layer of breathable mulch after the ground has frozen solid. This is typically a two to three-inch layer of material such as pine boughs, straw, or shredded leaves. The mulch insulates the ground, keeping the temperature stable and preventing the root crown from being damaged by repeated freeze-thaw cycles. It is important to keep the mulch material from piling directly against the plant’s woody stems, as this can trap moisture and promote fungal diseases. For Zone 3 locations or during predicted extreme cold snaps, covering the plant loosely with a burlap wrap provides additional protection from drying winter winds and sun scald.