Lavender cutting?

I live in a hot dry state in America and I have an English lavender plant. Does anyone know how far I can cut it back without harming it?

Lavender cutting?
Once it has finished flowering cut it back to 1/2 inch above the old wood.



Here in the UK we can get away with cutting it back into the old wood.
Reply:You cut it back after it has finished flowering, when the seeds are dry. Take the plant back until 2 inches ABOVE the brown woody stems. This gives the plant the best chance of lovely new growth next year.
Reply:after it has finshed flowering give it a hair cut like a trim