HARDINESS: Zones 4 to 9
PREFERRED SOIL pH: Neutral to slightly alkaline
PREFERRED SOIL TYPE: Sandy with added organic matter, well-drained
PREFERRED LIGHT: Sun
ATTRIBUTES: Small, rose-shaped flowers on low plants; for dry sites, rock gardens
SEASON OF INTEREST: Spring to fall
FAVORITES: 'Henfield Brilliant', 'Ben Nevis', 'Annabel', 'Raspberry Ripple'
QUIRKS: Remains evergreen in mild-winter climates
GOOD NEIGHBORS: Candytuft, hens and chicks, moss phlox, stonecrop, veronica
WHERE IT GROWS BEST: In sun and gritty or rocky, well-drained soil
POTENTIAL PROBLEMS: Grows poorly in extreme heat or wet soil
RENEWING PLANTS: Lives many years in mild climates; root stem cuttings in late summer
CRITTER RESISTANCE: Good
SOURCE: Bedding plants, cuttings
DIMENSIONS: 8-12 in (20.3-30.5 cm) tall, to 3 ft (1 m) wide
Sun Rose in the Landscape
Sun rose offers multitudes of fresh-looking, 1 in (2.5 cm) wide, single or double roselike flowers that cover the low-growing, shrublike plants in late spring to early summer. Flowers in clear, bright colors, including yellow, white, peach, red, and orange top stems clothed with small, gray-green leaves. Sometimes called rock rose, this flower delights in tumbling over stones, so it is a mainstay in sunny rock gardens. And because of its short stature, sun rose is also delightful as an informal edging plant or an accent at the front of a border. In container gardens, display sun rose alongside hens and chicks in broad, shallow clay pots and troughs.
Sun Roses Galore
Popular hybrids are a mix of Helianthemum nummularium, which is also called frostweed, and several other species that hail from high altitudes and exposed, rocky outcrops. In mild-winter climates the plants are often evergreen and can spread twice as wide as the same varieties grown in colder climates, where they become dormant in winter. Hardiness varies with each variety.
For a sun rose with fire-engine red flowers, consider 'Henfield Brilliant', which grows well in Zones 6 to 8, particularly on the West Coast. Plants reach about 10 in (25.4 cm) tall and 20 in (50.8 cm) wide. For a hardier plant, try 'Raspberry Ripple'. It's a good bet in Zones 4 to 9, with attractive gray-green leaves and red-and-white flowers. Other good choices for cold climates include 'Cerise Queen', which has double cherry red flowers; 'Annabel', which has double pink flowers; and 'Ben Nevis', which blooms with buttery yellow flowers.
Growing Sun Rose
Sun roses prefer a lean, well-drained, neutral to slightly alkaline soil. If your soil is heavy clay, amend it with sand and organic matter to lighten it. For acidic soil, add garden lime according to package directions. Set out potted plants in spring, or in fall where winters are mild. Allow 2 ft (61 cm) between plants so they will have room to sprawl as they mature. Keep the soil barely moist for a few weeks until the plants show signs of growth. Shear them back by half their height after they have finished flowering in early summer and expect a second flush of flowers in late summer or fall.
Sun roses benefit from protection from cold winter winds and accumulated ice or snow. In early winter,
cover them with evergreen boughs loosely piled over the crowns, or growing points, and remove the boughs first thing in spring.
Increasing the Bounty
Sun roses tend to be short-lived, especially in regions with cold, wet winters, such as along the Atlantic Coast. Take 3 in (7.6 cm) long stem cuttings in late summer and root them in moist soil under fluorescent lights indoors or in a partly shaded cold frame outdoors. After cuttings root, keep them fairly dry through winter and hold them in a cold frame, or in an indoor space that remains above freezing, until spring.
Tough-leaved sun roses are nearly impervious to pests and diseases, with the exception of fungal root rot when they are grown in cold, wet soil.