4. Cup Plant (Silphium perfoliatum) This 6 to 8 foot tall native perennial has a unique feature that makes it a star in Beneficial Borders. The leaves wrap all the way around the stems, forming a deep cup that collects dew and rainwater. Beneficial insects and small birds can easily use the leaves as landing pads, and then drink from the cups. Cup plant is an outstanding ornamental, with large attractive leaves and clusters of yellow flowers in mid to late summer that are highly attractive to many insects. It's hardy to zone 4 or 3. To start seeds, sow in fall, or store in damp sand in the refrigerator for 6 to 8 weeks before planting in spring.