Cistus x hybridus

Botanical Name: Cistus x hybridus
Common Name: white rockrose
Family Name: Cistaceae
Distribution/Origin: Europe

Description: In Pacific Northwest landscapes, rockroses are best planted in full sun, where they will receive no summer water. Most are suitable for Sunset zones 6-9 and 14-24 and many are already grown in zones 4-5; they are generally hardy to about 15°F. South- or west-facing walls and dry banks are perfect locations, assuming water drains freely from the soil year-round. Summer irrigation is unnecessary, as it typically produces a flush of unwanted growth and may predispose the plants to root or crown diseases. Shearing that excess growth is not advisable, since most rockroses resent hard pruning and quickly decline. They should be planted in the fall to ensure the plants will be well rooted and not require irrigation by the following summer. Natural companions for these plants are other mediterranean-climate plants, such as rosemary (Rosmarinus), lavender (Lavandula), Ceanothus, and manzanita (Arctostaphylos), although rockroses also combine well with informal, drought-tolerant Northwest natives, such as oceanspray (Holodiscus discolor) and flowering currant (Ribes spp.). As flowering specimens or groundcovers for the dry garden, Cistus have a lot to offer gardeners in the Pacific Northwest, as well as in other regions with some variation of a mediterranean climate. Some of the cultivars are becoming better known in the nursery trade, so gardeners will soon have a few more choices from this appealing genus. The flowers are simple, yet distinctive, with delicate, often crinkled petals that open in the morning and usually drop after only a few hours. The following morning, a new group of flowers will open; in most rockroses, the floral show will continue this way for two to three weeks. Some selections, notably ‘Sunset’ and C. inflatus, will flower sporadically for much of the summer. In general, however, the flowering time for Cistus in the Northwest is April through early July. The unscented flowers are usually white, pink, or purplish. The flowers of some cultivars may also have a distinctive reddish or brown blotch at the base of each petal. The source of this blotch is C. ladanifer, which is the only species with blotched flowers and which has conveyed this trait to numerous hybrid selections.

Notes: Broadleaf evergreen, Tolerates salinity, The leaves of some species, such as C. ladanifer, produce an aromatic substance called ladanum in abundance; it gives a shiny appearance to the entire plant and makes the leaves and stems noticeably sticky