LallyLuckFarm
Small scale permaculture nursery in Maine, education enthusiast, and usually verbose.
Possibly a potassium deficiency. Potash additives could help to address that, but there are a number of products that can increase the available K.
We have lemon thyme as well as your standard garden variety (hah!) thyme. They split readily to make new clonal cuttings, and I’ve rarely had one fail regardless of the timing of the division. We dry it for use in teas or for cooking, and it makes a good ground cover partner for plants like strawberries. The small flowers help to support solitary bees as well as parasitoid wasps, which help to regulate the insect pressure on the thyme’s plant neighbors.
Putting in a bioregion or something like a USDA zone (better if it’s Trewartha) would be very helpful for folks to know what to recommend. Here is a spreadsheet I made from the appendix in Edible Forest Gardens Vol. 2 if you would like too many options. This list is geared for the Northeastern US, so it is not exhaustive and may not apply to your circumstances.
Something I enjoy growing is Carolina Allspice, Calycanthus floridus. We strip and dry the bark for use as a cinnamon-y allspice type spice, whether grated or just used to stir a drink