Lavender plants need to be pruned every year, cutting off a maximum of 1/3 of the branch to prevent it from becoming woody and gnarly looking. This also encourages new growth and keeps it healthy looking. This should be done in August or September, after the flowers have died back.
If you plant has already past this stage then you can still prune it to try to get it back to looking nice and bushy but it will take some time.
Prune no more than 1/3 of the lavender plant. Leave for one year and repeat. You should notice that 1/3 of the length of the stems of the lavender is even further back towards the woody area. Make sure you do not right back to the woody area, there must be at least some new growth remaining.
Repeat annually until the lavender is back to a nice rounded shape. This will usually take 3-4 years of pruning. Do not be tempted to cut more than 1/3 of the stems as this will damage the plant, and may even kill it.
