Cistus, includes over 20 species of mostly compact, evergreen branching and spreading shrubs native to the Mediterranean. Very well known shrubbery and garden plants in the Mediterranean's warmer regions where they have grown since antiquity.
While some consider them course and unattractive Cistus are famous for their ability to flower profusely in poor, sandy, rocky ground, very dry spots, and when exposed to hot or chilling dry winds and coastal extremes. Their leaves are rather simple and olive or medium green and usually hairy, sometimes sticky. Flowers are large and simple five petaled nearly round blooms mostly in shades of mauve, pink, purple, occasionally yellow or salmon orange and classic white.
Many flowers feature a dark purple, red-purple or pink spot near the central base of each petal. The simple petal structure surrounded by many yellow stamens is reminiscent of a simple Rugosa, Beach or Coastal Rose which are also native species to the same coastal rocky regions of the Mediterranean, thus their common name: Rock Rose.
Once established, the Rock Rose is extremely drought resistant and somewhat cold hardy. They are excellent in baking hot locations and will withstand rather extreme coastal conditions, even salt spray and battering coast winds. But they are intolerant of cold, slushy wintry weather and often collapse when cold, wet, wintry weather combined with low light conditions persist. Limited cold, dry and sunny Winters that are more suggestive of their Mediterranean heritage will suit them well.
Their climate range extends through the entire Mediterranean and similar climatic regions around the world. They are excellent in rather arid climates with some artificial watering and will tolerate several degrees of frost and limited freezing provided the ground remains rather dry and sunny.
Cistus will perform well in rich soils, but avoid wet spots and close, humid environments or humid tropical heat. Nor do they like acid soils. Give them very open and limy land. Enriched land with Dolomite lime is often all they need. They do much better in very well drained soil and sometimes even very arid and poor land. In such positions they produce an active and spreading root system that sustains them through droughty periods.
This makes them excellent plants for coastal and slope erosion control. Yet the same plant grown in enriched and permanently moist garden soil will often thrive but put down very few roots. This makes them easily knocked out by roaming animals, misplaced Gardeners feet and strong winds.
While Cistus will survive some limited shading, their growing position must remain airy and dry or they soon succumb to leaf blight and root rot plus flowering is more limited and of lesser quality. The Rock Rose is one of those shrubs that thrive in full, strong year-round sunlight. Anything less produces somewhat inferior results. It is possibly for this reason that they sometimes receive an unfavourable reputation.
For when planted in an over-grown shrubbery border, or shrub and tree garden where they ultimately become crowed or overshadowed, they eventually thin out, weaken and produce less than spectacular flowering. This shrub stands out in the exposed and open situations that many other shrubs cannot tolerate.
Cistus is easily transplanted from containers anytime from Late Autumn through Spring. Mid Spring is an excellent time to plant Cistus for a handsome, bold show of colour starting almost immediately this Spring and continuing into Summer. But plan carefully where they are to grow, for Cistus is notoriously difficult to shift and transplant once it becomes established in the garden. Yet it is remarkably easy to transplant from established containers provided there is little or any major root disturbance.
When planting Cistus make sure the root ball sits at about the same level in the ground as it was in the pot. Avoid planting the root ball too deeply; or letting the root ball sink into the ground creating a depression that would collect excessive water around the plant. Planting on a small mound or sloping site guarantees the perfect drainage they need.
Once planted, firm the soil around the root ball and water in thoroughly to ensure there are no air pockets around the root ball that might dry the roots out or become a convenient home for rodents. Because these are sun-loving plants for exposed places, check regularly to ensure that the newly-planted Cistus does not dry out until its roots take hold and become established in their new location. Once all signs of wilting stop, the Rock Rose will need little if any maintenance.
Because the shrubs are relatively dense, low and spreading (usually 2-4ft/60-120cm; a few varieties 5-8ft/150cm-2.6m) they need little more than corrective pruning to remove diseased or misshapened growth. To keep them in a bushier condition, lightly shape and trim the shrubs by cutting off a few inches/centimetres of growth immediately after flowering. This shrub resents severe pruning. Branches should never be cut back beyond the last leaf or that bare stem will usually die.
To maintain compact growth on an established larger shrub species simply prune out a few canes right to the base each year, usually in Spring, allowing them to sprout dense new growth from the shrubbery crown. This new growth will soon fill out the shrub in preparation for flowering the following Spring and Summer.
Cistus make an excellent low border, foundation or hedge planting. The taller species make wonderful coastal windbreaks. Low species are excellent in the rockery, as a mass planting on banks, or cliffs and as a hardy container plant for half barrels, landscape planters and larger tubs.
Because of their preference for drier locations, Cistus seldom lasts for very long in smaller containers that must be frequently watered. Choose a larger container that always remain more evenly moist. Wherever there is the need for something colourful, evergreen, hardy and low maintenance there this little that will compare to the durability and rock-solid performance of the Rock Rose!