Rock rose 'Wisley Primrose'

Sun

Full sun; flowering is poorer and growth looser in shade.

Water

Water regularly while establishing, allowing the soil to dry slightly between waterings. Established plants tolerate drought but may need an occasional deep watering during prolonged dry weather.

Soil

Well-drained, preferably gritty or sandy soil of low to moderate fertility; neutral to alkaline conditions suit it well. Avoid heavy, waterlogged ground.

Height

0.5-1 ft (0.15-0.3 m)

Spread

1.5-2 ft (0.45-0.6 m)

Flowers

Pale primrose-yellow, five-petalled flowers with golden stamens in late spring and early summer; a lighter repeat display may follow trimming. Individual flowers are short-lived, but buds open in succession.

Foliage

Evergreen. Small, narrow, grey-green leaves on low, woody, spreading stems.

Growth

Moderate

Care needed

Low

• Pollinators
• Deer resistant
• Drought tolerant
• Low allergen

Northern hemisphere months. In Australia, shift them by six.

Difficulty

Easy

Toughness

Very tough

Pick your zone, country, light and whether you have pets.

1. Planting day

   0.7 ft (0.22 m)

   full size

About 5 years to full size.

From a typical nursery size, at an average rate for this kind of plant. A rule of thumb, not a forecast.

Cats and dogs

Safe

Growth rate

Moderate

• Plant with the crown at soil level in freely draining ground; use a raised bed if drainage is poor.
• Water during establishment, then mainly during extended dry spells.
• Avoid rich manure and routine heavy feeding, which encourage soft growth.
• Use a thin gravel mulch rather than moisture-holding organic mulch around the crown.
• In cold climates, shelter it from drying winter winds and avoid sites that stay wet through winter.

Pruning. Immediately after the main flowering flush, lightly shear off spent flowers and shorten the leafy shoots to keep the plant compact. Do not cut hard into old, leafless wood, which may not regrow.

Spring

Plant once the ground is workable and no longer waterlogged; water new plants during dry spells.

Mid-spring

Remove dead or winter-damaged tips, cutting back only to healthy leafy growth.

Early summer

After the main flower flush, lightly trim spent flowers and straggly leafy shoots.

Summer

Check newly planted specimens during dry weather and water deeply when needed.

Late summer

Take semi-ripe cuttings from healthy, non-flowering shoots.

Autumn

Clear fallen leaves from the crown and check that surrounding soil drains freely before winter.

• Plant along the front of a sunny border for a low ribbon of pale yellow flowers.
• Let it spill over a low retaining wall or the edge of a raised bed.
• Combine it with dwarf lavender and thyme in a gravel garden for contrasting foliage and successive flowers.
• Tuck it between rocks on a sunny slope, where its spreading stems soften hard edges.

Garden styles it suits: Dry gravel garden, Cottage garden, Mediterranean, Alpine rock garden, Pollinator garden and Low-maintenance.

Plant it with: Dwarf lavender, Creeping thyme, Candytuft, Dianthus, Blue fescue and Dwarf bearded iris.

Wildlife: The open flowers provide pollen for bees and other flower-visiting insects.

• Root and crown rot in wet soil: improve drainage, move the plant to a raised position and keep mulch away from the crown.
• Leggy growth and sparse flowering: provide full sun, avoid heavy feeding and lightly trim after flowering.
• Winter scorch or dieback: choose a sheltered, well-drained position and remove dead tips in spring once new growth is visible.
• Aphids on soft shoots: dislodge small colonies with water and encourage natural predators.

Not known to be toxic to people, cats, dogs or horses; no part is recognized as poisonous. It is an ornamental plant, not a food plant.

• Common rock rose (Helianthemum nummularium)

  Wild forms usually have stronger yellow flowers and often greener leaves. 'Wisley Primrose' has pale primrose-yellow flowers and grey-green foliage, although similar garden hybrids can be difficult to distinguish withou…

• Sage-leaved rock rose (Cistus salviifolius)

  This grows into a taller shrub with broader, wrinkled leaves and white flowers, rather than a low mat with narrow leaves and pale yellow flowers.

Helianthemum comes from Greek words meaning 'sun flower', referring to the flowers opening in sunshine.

Propagation. Take softwood cuttings in late spring or semi-ripe cuttings in summer and root them in a free-draining medium. Cuttings preserve the cultivar; seedlings may differ from the parent.

Accepted botanical name

Helianthemum

Sources: GBIF (CC BY 4.0). The care and design notes are LandscapeGPT's own.