Betony, Stachys officinalis was one of the first herbs that I grew that were not strictly culinary. It has a wonderfully colorful history as being a one-stop-fix for everything from arrow wounds to serpent bites, and bruises to tonics. More than that, betony makes a lovely herb for the garden. The mid green leaves come up reliably each spring around the time the doaffodils bloom and in late spring the pink flower arrives. The flower lasts for about 3-4 weeks, which is not too bad by perennial standards
What makes it a perfect perennial herb though is that the rosette slowly grows larger each year – not enough to need dividing every year, but just enough to be able to divide and give one to a friend when you want to.
So perfect polite perennials herbs have brightly colored blooms, do not set seed around the neighborhood and do not require division every couple of years, unless you want to. There is always room for perfectly polite perennial herbs in my garden.