I'm a great lover of herbs, so when I was reading La Repubblica this morning and a certain Chef Rubio named nepetella as one of his favorite ingredients, I immediately sought to clarify its identity. I ended up doing major research- confusion reigns supreme, even among Italians. In these cases, I always think that the botanical name is your friend. But there is still no consensus on this weighty matter.
Many Italians seem to think that nepetella is a synonym of the more common word mentuccia (and some think mentuccia is a generic name for mint.) But mentuccia should be Mentha pulegium (English pennyroyal),whereas nepetella is not in the genus Mentha L., but in the genus Calamintha (but both are in the Lamiaceae family.) In fact the botanical name for nepetella is Calamintha nepeta, possibly from the Etruscan city Nepete. This would translate to lesser calamint in English, although this term is not used for culinary purposes. Nepetella now seems to be standard in English for culinary uses. The authoritative Treccani dictionary states that mentuccia is used for both M. pulegium (pulegio) and Calamintha nepeta, but especially the latter. Some people have even gone so far as to mix nepetella up with catnip (Nepete cataria.)
As if this weren't bad enough, there are all sorts of regional names for these herbs. The confusion continues with the terms menta romana or mentuccia romana. Nepetella is in fact associated with Roman cooking, as in the recipe for Roman-style artichokes (not to be confused with artichokes alla giudia, also from Rome- its Jewish tradition). It is also good with mushrooms, especially porcini.
However you call it, nepetella is not easy to find in the States, although seeds can be obtained. The herb is said to be a cross between oregano and mint, and English-language recipes will often substitute other herbs for it. Even many Italian recipes do this.
Eager to try nepetella in a recipe? Here is Williams-Sonoma's take on Roman-style artichokes. And below you will find a photo of what is (probably) nepetella. I'm sure it's not catnip.