Everyone loves orchids, and our gardens are chockablock full of all manner of daylilies, hostas, penstemons--you name it. But who cares about milkworts? Well...I do! If you Google image Polygala you will an astonishing range of treasures found throughout the Northern Hemisphere, with some of the most outlandish restricted in nature to South Africa. Only a very small number have made it securely into North Temperate gardens, notably the alpine Polygala chamaebuxus, which you may find in early summer in the Alps, usually in its yellow phase.
The lovely pink milkwort above is Polygala amoenissima, although I had a very similar plant once labeled P. amara--both originating in the Caucasus of Western Asia. This has proved to be a very vigorous, long lived plant in my rock gardens, producing a few welcome seedlings to expand the display. Its first flowers can appear in late April, and it continues to sport its little pink orchids through summer and into the fall: quite a display for any plant.
I grew this blue gem for several years as Polygala vulgaris, although a simlar species (Polygala calcarea) is well established in British Gardens. Come to think of it, I remember that Betty Lowry found it to be almost a pest in Western Washington: I have yet to get a blue milkwort to persist for very long, although I have great hopes for Polygala hybrida, a taller kind I found everywhere in the Tian Shan last September. It has virtually the same habit and stature as the pink one above, only the flowers are always a brilliant sapphire blue.
I have seen so many tiny polygalas in Africa, and I've seen specimens of many more strange ones in Asia. I think this family still holds great promise, at least for rock gardens.
Who says all the best plants have been introduced?