I have several Phenomenal® lavender shrubs from Peace Tree Farm, a wholesale nursery in Pennsylvania. They have been in the front of my house for 8 years. Each summer they bloom profusely, attracting many bees. There are many types of lavender, but this is Lavandula x intermedia which works well as a hardy garden plant. Because of their highly fragrant foliage, deer don’t bother them. I have never had pest/disease issues. Now in August, the blooms are past their prime and the bees have moved on to other flowers in the garden. This is the best time to remove the spent blooms and to prune the shrubs to maintain their shape.
Although we think of lavender as a perennial, it really is a woody shrub that must be pruned annually. As the shrub ages, the branches become thick and gnarled, and they tend to crack and split. Annual pruning is necessary to prevent this with the branches and to remove the spent flower stalks.
A close up shows how far down the flowering stalk you have to cut.
To prune, look at the flowering stalks and where new growth occurred this year. Look for where the woody base ends and the new foliage growth begins. Cut into the new leaf growth but not into the woody section. Usually, the new spring growth you want next year will not occur in the woody section. Make your cut about 2 to 3 inches above the woody part and into the “green” part. You can use pruning shears or hedge shears depending on how many you have. Sometimes it is easier to cut off the stems first and then go back and shape the bush to create a symmetrical, dome-shaped appearance. Remove dead or damaged branches. Everything can go in the compost pile or save the foliage for potpourri.
Shaping it like this prevents the shrub from becoming a woody gnarled unattractive shrub. If left unpruned the shrub’s woody base will only get bigger, making it harder to cut and shape. Also, if left unpruned, it will develop fewer flowers. It is best to prune after the shrub blooms but no later than late August. Pruning in the fall will encourage tender new growth which will be killed by the cold winter temperatures. If you don’t prune in the fall, prune in the spring when new foliage growth emerges but before the plant blooms. Because my bushes are in front of the house and in front of spring blooming bulbs, I prune in the fall. I think the dead flower spikes are unsightly in the winter, and they detract from my spring bulb display.
Since its 2013 introduction of Phenomenal®, Peace Tree Farm has introduced Exceptional™ which has white blooms, Sensational!® which has purple flowers, and Inspirational!™ which has white flowers. All of these are winter hardy and perform well for us in the DC metro area. You should be able to purchase these from local garden centers. Lavender plants need full sun, plenty of air circulation, and well-drained soil. Good drainage is key so think about amending the soil or placing in raised beds.
