Cup plant (Silphium perfoliatum) is an herbaceous perennial plant in the sunflower family that is native to the central plains of North America, though found to be invasive outside of its historic habitat. Mature plants can reach 4-10 feet tall, with a stout central stem that is distinctly four-sided. Leaves are large, up to 8 inches long, and arranged opposite of each other aong the stem. They join together at the base, forming a cup around the central stem that can hold water. Leaves are coarsely toothed and have a very rough, sandpaper-like texture. Plants bloom in early to mid-summer, producing numerous 2-5 inch yellow flowers. Most flowers have 20-35 rays and a dark yellow center. Small achenes are produced in late-summer, releasing seeds that are spread by wind and water.
NOTE: If you receive a "sign in" message, click cancel to continue. Confirmed observations of Cup plant submitted to the NYS Invasive Species Database. For more information, visit iMapInvasives
Cup plant prefers moist soil and full sun, commonly growing along the banks of rivers and streams, in wet meadows, open forested wetlands, and right-of-way drainage ditches.
Threats & Impacts:
Native to parts of the United States, planting of cup plant has often been encouraged in New England. As a result, ornamental plantings have escaped to natural areas where the plants large growth form and high seed production allow it to crowd out desirable native vegetation.
Mechanical: Small plants may be removed by hand pulling or digging prior to seed set, taking care to remove the entire taproot.
Chemical: Apply a selective foliar spray application of glyphosate-based herbicide prior to seed set. Always consult and follow the herbicide product label.