End of Season Lavender Care
In the northern limit of its range, mulching Lavender plants in late fall will protect them from the winter's cold. Pile wood chips or bark mulch on the plants after a freeze. This will insulate them from the cold, but not cause them to rot. Remove the mulch in early spring.
Pests and Diseases: Pests & Diseases: Since lavender is very fragrant, many pests, such as deer and beetles, avoid this plant. However, in humid regions, powdery mildew and other fungus diseases can be a problem. Prevent fungal diseases from getting started by spacing plants further apart and in a location with good air circulation. This will keep the leaves dry and less likely to succumb to fungus.
Some insects, such as spittlebugs, whiteflies, and aphids, may attack your lavender as well. Knock insects off lavender with a strong stream of water from a hose. Also, sprays of insecticidal soap will kill these pests without harming other beneficial insects, wildlife, and pets. Spray early, before the pests become a big concern.
Dividing and Transplanting: Lavender does not survive well from being divided. To propagate lavender, take cuttings in the early summer. To make cuttings, select a healthy branch, take a 6 inch long cutting, remove the lower leaves, dip the cut end in rooting hormone powder, and place it into a pot filled with moistened potting soil or sand. Keep in a partly shady location and water well until rooted.
Another propagation method is layering. In spring, bend a healthy, 8-inch long, lower lavender branch to the ground, remove the leaves where it touches the ground, and scar the branch in that spot with a knife. Dust the wound with a rooting hormone powder, cover the wound with soil and leave the rest of the branch sticking out of the ground. It should root by the next year. Once rooted, cut it away from the mother plant, and transplant it to a new location.
Lavender also can self-sow if you leave the flower stalks on the plant. Decide if you want lots of baby lavenders in that area of the garden; otherwise deadhead regularly.