Cup Plant

Growing Cup Plant

Big and bold, so give it space at the back of a damp border. The fused leaf 'cups' really do hold water that birds drink from.

Where it belongs

Cup plant is a tallgrass prairie species of the Midwest, Plains, and parts of the Southeast and Mid-Atlantic, growing in moist prairie, along streams, and in low ground at the edges of woods.

It is one of the largest herbaceous perennials in North America, routinely reaching five to eight feet, occasionally more. That is a fact to decide about before planting rather than after. In a small bed it is a mistake. Along a fence line, at the back of a damp border, or as a summer screen, it is remarkable.

Growing it

Full sun to part sun, medium to wet soil, in loam or clay, zones 3 to 9.

The stem is square and the paired leaves fuse around it to form a genuine cup, several inches across, that fills with rain and dew. Chickadees, goldfinches, and warblers drink from those cups, and so do wasps and bees. It works best where there is not much other water available.

It grows fast and it grows big, and in rich moist ground it spreads by rhizome and by seed into a substantial colony. If you want one clump rather than a stand, plan on pulling volunteers each spring, or plant it somewhere a colony is welcome.

Do not stake it. The stems are thick enough to stand on their own unless they are shaded.

What it feeds

The yellow flowers are held at the top and feed bees and butterflies through midsummer, though it is the seed that draws the crowd.

Goldfinches strip the seed heads and will hang upside down on the stems to do it, and they use plant down for nesting late in the season. Chickadees, juncos, and sparrows take what falls. A large stand in September is one of the most bird-active things in a native planting.

Hollow stems shelter overwintering insects, and stem-nesting bees use the cut ends.

Living with it

Deer browse the young growth. Established plants outgrow the damage.

The lower leaves brown by late summer, particularly in a dry year. Plant something in front of it rather than trying to prevent that.

Leave the stalks standing through winter for the birds and the insects. Cut back in spring, and leave a foot of hollow stem where you can.

Sources: USDA PLANTS Database (native range); Lady Bird Johnson Wildflower Center, University of Texas at Austin (species profile); Cornell Lab of Ornithology (seed-eating songbirds and native plant food sources).

It’s showy, and fast-growing.

Where it grows

Cup Plant is native to the Midwest. In the wild you’ll find it across Alabama · Arkansas · Colorado · Delaware · Florida · Georgia · Illinois · Indiana · Iowa · Kansas and 26 more states. Always confirm it suits your specific county with your state native plant society before planting.

Regional Garden has written state guides covering Cup Plant in 36 of them so far.

Good for