Can I cut Lavender back?

I will take a photo of them in the morning and post so that you can see what they look like now. Thanks again.

The short answer is replace your plants. They have a finite life and yours appear to have reached the end prematurely because you have not previously trimmed them.

A lot of plants such as hebe and lavenders will only take a trim with a pair of sheers as they grow. The aim of the trim with the sheers each year is to hold back the inevitable progress of the new wood and thereby extend the life of plants such as these. Failure to trim simply hastens their ultimate demise as they grow increasingly more wood. Because when you cut into the old wood they will be very reluctant to sprout new growth.

You might find you get your own new seedlings if you let plenty of seed fall when pruning. This happened to me last year and now I have lots of small lavenders which hopefully will grow to a decent size this year.

Thank you both for answering my question. I will be digging them up as they look pretty bad. They came from someone elses garden so they have to be well over five yeras old. Thanks again...

They will take a bit of cutting back, tho as mentioned, much better to do a bit each year. If there are any shoots near the base, you could try cutting the plants back to those. Further to Chrispook collecting the seeds, you could also take cuttings if you wanted. They are not the easiest things to root, but if you have a cool partially shaded place to put the cuttings, use rooting powder and be careful not to bruise the leaves (as this leaves them suseptable to mould), then you could get some new plants going before digging up the old ones.