The rockrose (Cistus) is a low evergreen shrub blooming all summer long in pinks, purples, roses and whites. They range in height from the shortest variety at less than 2 feet (C. crispus) to the tallest at 6 feet (C. laurifolius). Native to the Mediterranean area and only hardy to -9 degrees Celsius, it does well in sunny spots in USDA zones 8 through 10, generally only in the south and along the Pacific Coast. The rockrose is useful in the landscape as a compact border shrub, linking flowers to larger shrubs and trees. If the correct location and soil are chosen, the shrub requires little ongoing care from the gardener.
Choose a hot sunny location for the rockrose. It is one of the few flowering shrubs that does well in windy spots next to the ocean and can tolerate salty air, but the shrub does need full sun and enjoys arid conditions once established. Do not place in a shady moist spot.
Plant in well-drained, loose soil on the slightly alkaline side. Test the soil pH with a soil test kit. Amend the soil by 50 per cent with builder's sand and well-aged compost if it is claylike or the pH is acidic.
Cut and gently untangle all circling roots that appear pot-bound at the time of planting. Spread these roots out in the planting hole so they can begin to grow downward rather than circling. If the cistus is not to be irrigated, the roots must penetrate to the deep soil.
Pull the excavated soil back around the base of the plant, gently tamping with hands. Water deeply for the young plant to get a healthy start. During the first dry season, water regularly, but once established the rockrose does not require irrigation.
Prune a few old stems from the established shrub every few years to keep the plant healthy and actively growing. Clip the tips off young plants to keep them bushy and control the shape of the rockrose.
Fertilise in the spring before bloom season with a plant food of three parts nitrogen, two parts phosphorous, and three parts potassium. The rockrose is pretty tough and hardy however, and may thrive just fine without this supplement.
The cistus shrub is a drought-tolerant plant. It will not thrive in a wet, soggy location in the landscape.