Don't know if this will help you, but, I did grow lavender last year - near Nashville. My flower bed had about 10 inches of compost and manure mix. Underneath, of course, is our wonderful tennessee clay which i mixed with the compost and manure as much as i could. The lavender did great and was very healthy, even with all the rain. I expect it to come back on its own this year. Can't wait!!! LOVE the smell of lavender.

Good drainage is a must - a raised bed is a good way to go if you aren't on a slope. The other important thing (besides sunshine) is alkaline soil. We have that in many places in Nasvhille, but it's not likely that's what you have in Knoxville. I would recommend getting a soil test - if your PH is anything lower than 6.5 or 7.0, you are going to have difficulty growing lavender. It's not impossible - but you would have to replace a great deal of soil and treat it regularly to keep the PH high.

A friend in west Knoxville has kept Lavender and Rosemary alive for many years. Each year she replants them in fresh grit with a very small amount of soil added. Lavender goes in chicken grit that is crushed up shells; rosemary goes in granite chichken grit. I think she gets them at an ag supply place over near Oak Ridge.

I love lavender! Unfortunately in my experience they look great for about three seasons then they buckle from the humidity. Is it worth it? Heck yes! I will dig a twenty dollar hole for a two dollar plant that is short lived because they are so intoxicating. My method is a third part sand, a third part compost, a third part native soil. Mulch with sand and you will increase the oil content therefore increasing the lovely aroma!