Vaping different herbs can require different technique just like vaping different strains of Herb. They key point is always not to burn whatever you're extracting. The procedure for vaping Lavender is close to identical to that for vaping high quality sticky crippy Herb. The procedure for vaping TEA tea, camellia sinensis, is closer to that of vaping dry-ish brick weed.
But why vape a plant? For sensory pleasure or medical effect (including pleasure). So the question is, are the benefits accessible through vaping? Most aromatic and tasty things are made more so by hot air, so these benefits are usually accessible. Mint, thyme, lavender, and many others often have visible trichomes (or analogous anatomy, though in these cases I believe they actually are trichomes) that contain their aromatic actives. Tea does as well, for that matter, and there are a variety of smells and tastes that it can produce.
On to the medical question. Caffeine appears (to google) to boil at 352 F which is accessible through vaping, so it should work. I have smoked tea and got a buzz, more than just the I'm Smoking Something buzz, and I've also abused caffeine in a variety of ways and so am sensitive to its nuances. I vaped some dry whole rolled leaf oolong and it was tasty but didn't form a thick vapor. Was too high to notice if I felt much from it.
But lavender... the first hits are quite tasty and beg for more. after a couple of bowls, a line is crossed and it can drop you into an intense state of relaxation and sedation. a noticeable and useful buzz for sure. but... I am unsure as to the long term effects of vaping lavender flowers as lavender oil is somewhat cytotoxic and shouldn't contact skin too much in pure form.
In other words, have fun and try it out. There are certainly many things other than weed and tobacco which have true, noticeable effects when smoked, and some of them can be used with vapes too.
Report back!
Edit: Many aromatic compounds such as the terpenes and terpenoids found in Herb and other herbs have dramatic medicinal and recreational properties, so don't underestimate them. Both in so far as you shouldn't fail to try something seemingly psychoactively neutral, but also in so far as a usually benign substance can become toxic in concentrated form. One drop of rosemary oil might be fine and useful, but 5 can give you a serious headache (and more). So be very careful, too.
