Answer: If the flower buds are drying out before they have a chance to open, I suspect your plant is getting too much reflected heat from the wall. Reflected heat will dry things out and flower buds are especially prone to dying when humidity is low. Try moving your plant (container, trellis, and all) to a site that receives afternoon sun but not reflected heat. I think you'll see an improvement in the flowering of your plant. You can repot it when it outgrows its current nursery pot. Move it in the winter when it is not actively growing and transplant shock will be lessened.
Best wishes with your lavender lady.
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