Silver Edged Horehound

Silverheels horehound is a low, vigorous evergreen perennial grown as a silver-edged groundcover. Rounded, felted gray-green leaves with pale margins form a soft mat, with small white flowers from late spring into early summer. ## Landscape use Use it in rock gardens, dry borders, or as groundcover around stones and edging. Plant Select describes it as 4 inches tall and 18–30 inches wide, with white early-summer flowers; Conservation Garden Park lists 10 inches tall by 18 inches wide and May–June bloom. These mature-size and timing ranges differ, so allow space for a spreading mat and expect local bloom dates to vary. See the [Plant Select Silverheels profile](https://plantselect.org/plant/marrubium-rotundifolium/) and the [Conservation Garden Park profile](https://conservationgardenpark.jvwcd.gov/plants/358/silver-edged-horehound/). ## Growing conditions Give it full sun and sharply drained soil. Plant Select advises against frequent irrigation, poor drainage, heavily amended soil, and overhead watering in the hottest weather. Water during establishment, then let the soil dry between deep irrigations. Regional profiles note deer resistance and pollinator value. ## Maintenance Trim dead foliage in spring after assessing winter damage. Shear spent flowers or trim the mat lightly if it grows beyond its allotted space; deadheading is optional.