This is for an urban garden in downtown Toronto. I purchased lavender at a nursery store sale in 6″ diameter pots. They are fairly large size at about 12″ high. They were on sale obviously because of the late season and the need of some TLC. The foliage looks healthy although the bottom of the stems looked woody and dry. I was wondering what my options were. Can I plant them outside now or is there a possibility of keeping them indoors for the winter and plant them in the spring? Should I fertilize them? Thank you!
The first step to growing lavender successfully is to know what type of lavender you have. There are basically two varieties of lavender that are hardy in the Toronto area (z. 5/6)–Lavandula angustifolia ‘Hidcote’ and ‘Munstead’, otherwise known as English lavender.
Lavenders, native to the Mediterranean areas, are very drought-tolerant sub-shrubs requiring a full sun location in good-draining, gritty-gravelly alkaline soils. Once established, they require only pruning in the late fall or in the spring. The typical Toronto alkaline clay soil would need to be amended for better drainage with humus and gritty sand; otherwise, the lavender would be susceptible to root rot and not survive. Good drainage is key to successfully growing lavender.
Fall can be a good time to transplant plants into the garden; if your soil conditions are good for lavender, one might be able to put the plants into the ground before the weather becomes too cool; alternatively, one could bury the pot in the ground in a protected area of your garden for the winter and transplant the lavender in the spring. However, make sure that you provide winter protection with a mulch of straw or dry leaves once the ground freezes in either case. Nevertheless, you may decide to overwinter the plants indoors and transplant next spring. [See below].
Lavender does not need to be fertilized as it prefers soils with low fertility.
Many garden centers have been selling another species of lavender (Lavandula stoechas) in pots for summer interest–it “bears intriguing pine-cone-shaped flowers that have dark-purple bracts, or ‘rabbit ears’.” http://www.finegardening.com/french-lavender-lavandula-stoechas . This lavender, known as French, Spanish or butterfly lavender, would definitely not be hardy in the Toronto area. Overwintering this lavender indoors may be the only option for you.
To successfully overwinter indoors, please see: http://everything-lavender.com/growing-lavender-indoors.html.
Lavender is a wonderful addition to one’s garden–if it’s established in a sunny location in soil that provides good drainage, it is basically trouble-free. All one needs to do is prune it back by a third in the fall or prune back to the new growth in the spring.
Good luck with your lavender.