It is evergreen in places where the winter is mild, and grows 1 to 3 feet tall (30 cm to 1 metre.) It blossoms with very tiny star-shaped flowers.
The stems and leaves are used as an herb. Per stem, there are three small green leaves, somewhat heart-shaped, up to 3 inches (7 1/2 cm) wide.
Some varieties have green stems, some have white stems.
The leaves will turn yellow in dry, hot weather. Slugs love it, and will attack it like mad.
Trefoil is cultivated in China, Japan and Korea. In Japan, it is even grown year-round in greenhouses. In cultivation, the plant is often blanched, either the whole plant by growing it in darkness, or just the stems, by mounding up earth around them.
In Japan, depending on how it’s grown, it’s called either Ne-mitsuba, Kiri-mitsuba or Ito-mitsuba.
- Ito-mitsuba is grown hydroponically, and sold with small sponges around its roots so that it doesn’t dry out. It is used as a soup garnish;
- Ne-mitsuba can be simmered, or used in the small salads the Japanese call “aemono.”
Trefoil can be cooked as a pot herb, or used raw in salads or as a garnish on dishes.
When using Trefoil in cooking, add it at the end of cooking: if cooked for a long time, it can turn bitter.
The Japanese name “mitsuba” means “three leaves.”