Hi Susan,  

Thank you for contacting the helpline with your question. For the best results you want to make sure you are planting cold-hearty lavender varieties such as: “Munstead”, “Hidcote Blue”, and “Phenomenal” - these are know to be cold hardy down to zone 4.

PRUNE: You should prune the lavender plants back in late summer/early fall. (cutting the plants back too late can make them more susceptible to winter injury) Don't prune more than 1/3 of their length and don't cut into the woody (old) part of the stem, always cut into the new (green) growth. Use this time to shape the plant for spring growth. Also, don't prune brand new plants - wait until they are in the 2nd season of growth before pruning.

MULCH: Cover the base of the plants with a well-draining mulch or straw. This will insulate the root system and regulate soil temperature without retaining too much moisture, which could lead to root rot. Avoid heavy mulches like leaves or grass clippings that can trap water and create a damp environment. 

COVER: After the first hard frost you can winterize the plants by covering them with row cover, burlap or old blankets to protect from the cold weather. Lavender goes dormant when the cold weather arrives, so make sure not to cover them before a hard freeze as they may stay too warm and get confused. Best time to cover is when night time temps are consistently in the 20's. Remember to remove coverings as soon as the risk of frost is over in the spring. 

I hope this helps...please don't hesitate to reach back out if you have any other questions.

Hi susan,

I also wanted to add that Lavender needs well-drained soil, especially through winter. Sandy, sandy loam, or gravelly soils are ideal. It will struggle with heavy clay or poorly drained soils. Moreover, lavender prefers more alkaline soil (so a higher pH) but pH can be adjusted using soil test recommendations for any soil. I recommend getting your soil tested to be sure your soil has the appropriate nutrients to help your lavender thrive.

Best of luck this winter!