Gardening with Gary

Gardening Advice from an Expert

Lavender

T. VanEgmond, London, Ontario, Canada writes~
I have some very large and woody lavender plants. The lower portions have lost all leaves/foliage, and as mentioned are very woody. If I separate or thin out the plant, will it address the woodenness? If so, how do I do so?

A. To be a vigorous healthy plant, lavender needs to be pruned. This should begin when the plant is young and continue each year. English Lavender (Lavandula angustifolia) needs pruning after flowering in summer. Italian Lavender (Lavandula stoechas), with the ribbon-like flowers, can be cut back by one-third or even one-half in the fall. For both these varieties, cut the stems below the flowers and the top leaves. It is essential to cut into green growth, not the old wood at the base of the stems, allowing some leafy green stem to remain below the cut.

French Lavender (Lavandula dentata) needs to be controlled, especially if it is a hedge. Using shears, trim it back in summer, leaving no flower stalks. To prune in a moderate fashion, just remove the immature growth. If the bush needs a hard prune, reduce it by half. Do it regularly so that the bush does not become woody in the center.

Certain varieties benefit from pruning off the old wood in early spring (these varieties produce new growth at the base of the plant and you will see it) and some varieties do not. After transplanting lavender, do not expect much flowering until the roots reestablish. You will see some new growth and maybe a few blooms in later summer. If you've planted it in a very sunny, well-drained area it will really take off next year.

The only lavender I really prune hard is the munstead. It gets new growth in the middle in the early spring, and I prune out all the sprawling old woody stuff around it. It comes back very full and lovely. With provence and hidcote, I shear off the old flowering stems lightly and cut off anything that's old and woody with no foliage.