Pruning Lavenders is essential to promote more beautiful blooms and get a healthy, nicely shaped, mounded shrub that will last for years. If these rules are not respected, you might end up with a shabby, sprawling shrub. 

Pruning your Lavender will prevent your shrub from turning to wood. This is important because the parts of the plant that turn to wood will not produce new lavender stalks. Additionally, a woody plant is prone to cracking or rotting in winter.

Pruning Lavender differs with the type of Lavender you're growing

• Lavandula angustifolia - also called English Lavender, True Lavender, or Common Lavender:
  These Lavenders usually bloom once but may experience a weak second flush after pruning. Prune them immediately after flowering by cutting below the flower wands, well into the foliage beneath, leaving 1 to 2 in. (2-5 cm) of foliage below the cut. Always make sure there are green leaves left on your lavender when you are done pruning. If all the green is gone, your Lavender will die. Expect your Lavender plant to live 20 years or more.
   
• Lavandula x intermedia - also called Lavandin:
  These late-season lavenders typically bloom in July or August and tend to last until late summer. Similarly to Lavandula angustifolia, prune them after flowering by cutting below the flower wands, well into the foliage beneath, leaving 1 to 2 in. (2-5 cm) of foliage below the cut - even if you have to sacrifice some late flowers. Expect your Lavender plant to live 20 years or more.
   
• Lavandula stoechas - also called Spanish Lavender or Butterfly Lavender:
  Since these Lavenders flower almost continuously from spring to fall, it is not obvious to figure out the best time to prune them. The general rule is to prune them immediately after the first flowering by cutting below the flower wands, well into the foliage beneath, leaving 1 to 2 in. (2-5 cm) of foliage below the cut. Deadhead for the rest of the flowering season and continue to shape the foliage into a rounded, mound - including a gentle trim in late summer. Expect your Lavender plant to live 5 to 10 years.

Pruning Lavender tips

• When pruning your Lavender, never cut into the woody part of your Lavender. Always make sure to leave the leafless wood intact, since cutting it could injure the plant. A good rule is to prune two leaf sets above the woody part. This will encourage stable growth and a healthier, thicker lavender plant. 
• Always use a very clean set of pruning shears or secateurs that have been washed clean of dirt and disinfected with a bleach solution. Taking this precaution will help ensure that your Lavender plant doesn't pick up a bacterial disease. You should also make sure the shears are very sharp so that they make a clean cut that will heal over quickly.
• Never prune just before winter as Lavender needs some foliage to protect it against the winter cold. If you prune too close to winter, your Lavender may die from the cold.