Cobalt-n-Gold St. John's Wort

Cobalt-n-Gold™ is a compact cultivar of Kalm’s St John’s wort, sold by First Editions as Hypericum kalmianum ‘PIIHYP-I’. This mounded shrub has blue-silver foliage and bright yellow flowers in late spring and early summer; First Editions lists it at 2–3 feet tall and 4–5 feet wide for USDA zones 4–7. The [First Editions page](https://firsteditionsplants.com/product/cobalt-n-gold-hypericum/) binds the trade name to this botanical selection. ## Seasonal Character and Use The yellow flowers are followed by orange fall foliage. First Editions recommends the plant for borders, foundation plantings and low hedges, and describes it as pollinator-friendly. Its plant patent identifies Joshua H. Kardos and Michael A. Dirr as inventors and Plant Introductions, Inc. as assignee; U.S. Plant Patent PP25,318 issued February 24, 2015. The patent describes the denomination ‘PIIHYP-I’ and compact, mounding growth. [Patent record](https://uspto.report/patent/grant/PP25%2C318) ## Siting Choose full sun and well-drained soil for this selection. North Carolina State Extension describes the parent species as adaptable to moist or dry sites while preferring drainage; its profile also notes that St. John’s wort foliage can be toxic to livestock and may cause photosensitivity, especially in light-colored or thin-haired animals. Keep grazing animals away. [NC State Extension](https://plants.ces.ncsu.edu/plants/hypericum-kalmianum/) and [University of Illinois Extension](https://web.extension.illinois.edu/shrubselector/detail_plant.cfm?PlantID=359) provide regional species-level growing context. ## Maintenance First Editions lists early-spring pruning, while NC State Extension advises pruning after flowering or in late fall if shaping is needed. The sources differ on timing, so prune lightly to maintain form, avoid cutting the shrub to the ground, and use local flowering timing to choose the season.