I am reluctant to spray edible plants like herbs with too many chemicals, so I have been forced to accept that in my garden Thyme needs to be grown as an annual, not a perennial. Most years I buy a few potted Thyme plants and put them either in bigger pots or in the border. This is one of last year's plants:
They get cropped until they succumb as described above, then are replaced by new ones. This can be expensive, but fortunately this year it probably won't be necessary - because of these:
Last Autumn I realised that my most recent batch of purchased Thyme plants had self-seeded after flowering, so I potted-up some of the seedlings and kept them over the Winter in my coldframe. They are now quite decent little plants.
I have planted some of them in the border over by my fruit trees.
I wonder how long they will survive???