This sweet lavender (Lavandula heterophylla) is not hardy for us. Gardeners in the deep south or far west and south (like Zone 9 and south) are lucky enough to put this in the ground. I would not use the flowers from this in cooking. I would only use Lavandula angustifolia varieties, such as 'Hidcote' or 'Munstead' as long as it says angustifolia on the tag.
The only lavender outside the angustifolia variety of lavender would be one called 'Provence' in the Lavendula x intermedia varieties. It is mostly hardy for us. I was in love with it and during one cold wet winter several years ago, I lost 8 plants. It was devastating! This sweet lavender because of its size will either be in the garage (my favorite place for herbs) or the basement. It may not have enough light in the basement and that becomes the real issue for herbs in the house, light. The tag along plant is a nicotiana that seeded somehow. I don't know how The Herbal Husband does it sometimes! Those Peruvian tricks! Well, the air is very brisk here and we are really wet! We have a closed low that just keeps spinning around. My grass is like a field and the weeds that I haven't gotten to weed are going to be great Halloween decorations! That's my story and I'm sticking to it! Hope you are having a great day in autumn. Talk to you later.