Lovely white flowers of Cardamine trifolia grace the April landscape at Heronswood in Kingston, Wash.

A woodland plant that I’ve fallen in love with over the years is European native Cardamine trifolia. Plants of the genus Cardamine (pronounced car-dam-in-ee) are commonly known as bittercress, which at the mention of that name, many nursery professionals call foul and whip out the penalty flags! After further review however, Cardamine trifolia is a dainty, graceful gem in the woodland garden, while its cousin, Cardamine hirsuta, or hairy bittercress, is an invading thug that flings its seeds with explosive force, sometimes up to 10 feet or more. The former is a beautiful, well-controlled evergreen groundcover, the latter, a menacing scourge.

C. trifolia grows to about 6 inches high and forms a slowly spreading circular clump that can be 1 foot across. It thrives in varying degrees of shade and is widely adaptable to many soil types including clay and sandy loam. It prefers moist, well-drained soil, and after it establishes, it is somewhat drought tolerant. Regular summer water will keep the plant tissues turgid and looking fresh. In spring, C. trifolia produces a dainty cup-shaped white flower. It may have other smaller flushes of bloom in the fall as well, especially if it had plenty of summer water.

C. trifolia is most commonly propagated by division, however seed is also available. This is a plant I definitely feel should be more widely available in the trade and more widely used in high-end landscape projects where the goal is to create a unique garden with rare and unusual plants. It’s a perfect companion plant to place in a stumpery or other shade garden constructs. Another virtue of C. trifolia is that it is practically maintenance free, aside from a minute or two each summer to remove flower stalks that have finished blooming. So, the ruling in the garden stands. This is a plant that just keeps giving all year long.