This plant is head of the list in the 2023 Flower Walk records. It puzzled some of us for quite a while, on the day of the walk in April, because without flowers members of the mint family can look similar. The large clump crinkly leaves on the western “covers” are Black Horehound and it is still out of flower as this is written, at the end of April.
Typically flowering is in June and it may be up to metre tall with whorls of purple mint-like flowers, each whorl subtended by a pair of leaves, on a long upright stem.
“Horehound” comes from Old English “hore” for greyish-white. In middle and modern English, “hore” has become “hoar” as in hoary hair or frost. “Hound” is less clear but OED suggests a Horehound was used as a, now obsolete, cure for the bite of a mad dog i.e. one with “rabies”. But Black Horehound is not black or white. As noted, its flowers are purple.
So why “Black”? This seems to have been applied to indicate that it was NOT “White Horehound” which looks quite similar out of flower with the same crinkly leaves of similar shape. This was the plant that was and still is used medicinally, but only for coughs and colds. Its use for dog bites was abandoned long ago. As you might expect from the name, its mint-like flowers ARE white but still in whorls up the flowering stem. Thus, this was THE original Horehound. The purple flowered, similar leaved, plant was the “Black” or useless one and with a rather unpleasant smell as well.
Botanical classification now puts them in different genera. White is Marrubium vulgare. Black is Ballota nigra and there are several other species in both groups. These other species are mostly seen as garden plants in this country and none of them are native. The Black Horehound is quite a common wildflower around here but to find the White one you may have to trek up to the grassland of the Downs. Look for areas disturbed by rabbit burrowing. Please do not pick it for making an infusion for your cough or cold. As a native species it is declining in this country. So, please, just admire it if you come across it. Interestingly, when it was a more common grassland plant, it was transported with grass seed to, for example, South America and Australia where it has become an invasive weed.
Botanical Latin names.
Marrubium This was the name given to one of Mediterranean species by the classical Roman naturalist Pliny (who died “with his boots on” observing the eruption of Vesuvius). It is thought to derive either from the name of a Roman town in central Italy and now called San Benedetto dia Marsi. Alternatively, he may have taken it from the classical Hebrew “marrob” ( מרוב) meaning bitter juice which can be produced from the plant. The species name “vulgare” means “common”.
Ballota This was the name used (probably) for this plant by a Greek doctor and botanist called Dioscorides, a contemporary of Pliny (1st C.E.). nigra is, of course, black which was probably applied later, though its dried leaves do go black. Greek “ballo” (βαλλο) meant “reject” as you might well do because of its smell, if offered it to eat or as herbal remedy.
Brian Livingstone
