Sometimes Lavender tends to grow that way don't they. I see it as some what of a downfall in their growing habit. I am sure someone with more
knowledge will come along and correct me if I am wrong. The good news for you is this can easily be corrected by a few simple pruning steps.
The plant may not flower for a few years but that is often the nature of it's business. ;-]

I am assuming this plant has never been pruned up until now. You will probably need a few steps to correct it's growth, especially outward
bound and yearly pruning is defiantly a must in keeping the plant in a nice tight pleasing shape yet not falling out of it's natural shape.

First try this ;- Early spring.

~ Since you say your plant is a good size clump, I would recommend pruning away the outer branches all the way flush with the main trunk.
Even meaning cutting them back all the way down to the soil line. For example if your clump consists of 15 branches trim 5 away.

Please bare in mind how Lavender or any other plant responds to the pruning also depends on it's growing conditions. If you have it planted
in an ideal location along with well drained soil and proper watering regiment you should see the plant put on abundant growth in no time at
all.

You will need a different corrective pruning technique in the upcoming summer and then again in fall please bring it to the forums attention
then. I am sure that many of us will gladly help you. I am of course here from time to time.

Happy Pruning!

Ankrara's Hobby Corner

In my experience lavender does not like to be pruned back into the old wood -it will often not regrow from there. So we can only prune back into this year's green growth.
That means to avoid leggy bushes that fall open, we need to be quite diligent about giving it a good haircut each year after flowering. We are not diligent enough, so when a plant gets leggy and falls open, we take cuttings, and when they are established we replace the plant. This is for the UK climate - I have spoken to a gardener in Spain who, with the warmer climate, is able to get lavender to regrow from after pruninginto the old wood. Good luck