Lavender plants are easy to grow in most temperate climates. They need hot, sunny summers and cool winters. Lavender is fairly drought resistant and needs little water. Lavender plants take three years to mature, and they produce well for another three. After six years the plants can become woody as they reach the end of their life. Lavender plants that have been left to grow without pruning can become straggly and unruly. Proper pruning will revive old, large lavender plants as long as they are not too near the end of their productive growing life.
Cut back one-third of the lavender plant In the late spring and early summer. Cutting the lavender plant back will cause it to put out denser growth that will be closer to the base of the plant. Use sharp pruning shears and clip the plant to follow its natural dome-like shape.
Allow the new growth that appears continue to grow for a month or so and then cut it back by half. You will know your pruning was successful pruning when new growth begins to form at the base of the plant.
Prune out old growth so that it is just 1 or 2 inches higher than the new growth forming at the base. When pruning out old growth take only the stalks that are green and budding. Never cut down into the old woody growth that does not have green buds on it. Pruning the old woody growth too heavily can prevent it from producing in the future and may kill the plant all together.
Cut off the flowers at the base of their long stalks. This will leave the bushy leaves on the plant and allow for new growth in the following years. Future pruning should be done in the summer when the purple flowers have formed.
Collect cuttings in case your plant does not survive the pruning. Lavender plants usually only live for six years, but they are easy to propagate.