Hypericum calycinum – Rose of Sharon (south-eastern Europe, western Asia)
Habit: Semi-shrub with runners; 0.2-0.3 m tall, covering large areas, fast-growing.
Flowers: One bright yellow bowl flower per shoot some 5 cm wide with many radial stamen, main flowers in July, second blossoms in September.
Leaves: Semi-evergreen, sometimes evergreen; oval, hard and leathery, dark green.
Roots: Shallow, forming runners, 0.5-1m long runners; sensitive to soil compaction.
Demands: Sun to shade, tolerates heat, sensitive to frost, indefatigably regenerating after damage; good for urban areas.
Soil: Moderately dry to fresh, acidic to slightly alkaline, well drained soil; sensitive to heavy soil; tolerance of chalk often overestimated, tends to have chlorosis (yellow leaves); sensitive to salt.
Note: Has to be cut back hard every year after frost damage to further ground cover and flower production; can be cut with a raised lawn mower.
Hardiness: Zone 6b