I also did not grow Lavender from seed. This plants is one of the babies of the "mother plant". The mother plant was killed last year by my ex-gardener (I think you can guess why I let him eventually go). This plant can really handle a lot: not very fussy at trimming, does not need much water, etc... However, anything very radical will kill it, and it did :-)
I do not use lavender as an herb, as I do not know exactly where to use. However, I love the plant, and the flowers. I am about to trim the flowers, and a little of the height. I will also check if I can find some "soft" wood parts so I can start new babies (you never know when you will "need" another one.
One thing about Lavender that you should be aware is this plant attracts bees. For me, that is a plus, as my fruit trees are near by the Lavender plants. However, if it was close to where I have to go through, I would not choose this plant.
Do you cook with Lavender? What do you make? How do you use it?
Luiza