I always rnjoy Rachel Roddy's coolery column in the Guardian, more for her descriptions than for her recipes. I was not in the slightest tempted to cook last week's chocolate and rosemary panna cotta - I didn't even feel much desire to eat it - but I loved what she had to say about aromatic herbs. Their scent, she argues, seems made for our culinary pleasure, but a form of self-defence, a weapon against both both predators and competitors.
Rosemary is particularly kick-arse in this respect, with those volatiles (mostly organic compounds called terpenoids) synthesised and stored in minuscule glands that project from the surface of each dark green needle, which breaks when brushed against or bitten, releasing an intense, hot, bitter shot. It’s the evergreen equivalent of carrying personal defence spray. The needles also mark territory. By leaking their volatiles into the nearby soil, they inhibit the seeds of other plants (maybe even their own) from taking root and, in turn, taking space, water and precious minerals in a challenging environment.