Botany
Tea is Camellia sinensis, a single species in two main varieties, and every one of the six tea categories comes from it. Herbal infusions come from unrelated families — daisies, mints, legumes, grasses, gingers — with nothing in common but being steeped in water.
Processing
Tea’s categories are defined by processing: oxidation stopped early gives green, run to completion gives black. Botanicals are mostly dried and that is all, with roasting the main exception. There is no botanical equivalent of the six categories because there is no shared process to categorise by.
Brewing
Tea is temperature-sensitive and time-sensitive, and green tea punishes both. Most botanicals are neither: rooibos takes boiling water and five minutes without turning bitter, and roots and barks need to be simmered rather than steeped at all. Advice that transfers between them is rare.
Caffeine
Tea always contains caffeine. Most botanicals contain none — but not all, and the exceptions are not obscure. Yerba mate is drunk by millions daily and is a caffeinated infusion.
What can be claimed
This is the difference that shapes TeaHQ most. Tea’s flavour, origin and processing are checkable facts. A great deal of what circulates about herbal infusions is about their effect on the body, which is a different kind of claim requiring a different kind of source — and where TeaHQ does not yet hold one, it says so rather than repeating what everyone else says.