Aaron's beard

Aaron's beard (*Hypericum calycinum*) is a spreading groundcover with large yellow summer flowers and a low mat of foliage. Underground stolons help it cover slopes and naturalized spaces quickly, but can let it overrun smaller neighbors. [NC State Extension](https://plants.ces.ncsu.edu/plants/hypericum-calycinum/) lists USDA zones 5a–10b, while [Oregon State University](https://landscapeplants.oregonstate.edu/plants/hypericum-calycinum) warns that it has become invasive in parts of the Pacific Northwest and California. ## Site and seasonal interest Plants typically reach 12–18 inches tall and 18–24 inches wide; the five-petaled flowers are about 3 inches across. It flowers best in sun but tolerates shade, and grows in well-drained acidic loam as well as dry soil or heavy clay. This is not *H. perforatum*, the medicinal St John's wort; NC State reports high-severity poisoning if eaten and possible contact dermatitis. ## Maintenance Water new plantings through establishment; established plants tolerate drought. Edge the planting or remove runners where spread needs control, and use gloves if sap irritates your skin.