If gardeners and landscape maintenance workers can manage the irrigation, Cistus ladanifer provides a lot of bang for the buck in a drought tolerant garden. I emphasize this caveat for a simple reason unrelated to general skills within maintenance services. Rockroses behave similarly to our own California wild lilacs in regards to water. Both are native to summer dry climates and have adapted to needing little water through the summer season. In ornamental landscapes, however, regularly scheduled irrigation, such as weekly run cycles, will simply be too much. In their youth, these plants appreciate the head start moisture, but as they become established, less water is needed or even appreciated. If the watering schedule is not reduced over time, they can succumb to rot. And this is the crux of what I have observed over my career as a designer, contractor, and arborist. Water is all too frequently mismanaged, which is concerning for drought tolerant plants native to Mediterranean climates. Unfortunately, watering schedules are difficult to program for less frequent watering, but today their are smart controllers that can manage such tasks.
Cistus ladanifer is one of the showier rockroses, with large white blooms that pop against their dark green leaves. Its showiness lends use in informal hedges or as background for smaller bloomers, because you know, white goes with anything. Similar to the watering concern, rockroses need great drainage, so combine with other species that like rocky soils. Note: While not listed on the California Invasive Plant Council's species list, naturalized specimens have been spotted in Southern California, including video observations by a hiking group.
'Blanche': For a cultivar, this one is large, possibly reaching 8' tall by 5' wide. Given the size of the buds, I'm expecting large white blooms. Apparently, it was cultivated right here in California by the early owners if Western Hills Nursery in Occidental. I'm looking forward to seeing it evolve in the garden.
Apparently, it can be grown throughout low elevations of California but also as far north as Portland.
C. l. var. petiolatus 'Bennett's White': Has similarly larger flowers to 'Blanche', but they present a crape-like texture to the petals, leading Sunset to compare blooms to California's native Romneya coulteri (p. 245). In truth, the latter's blooms are considerably larger, but the resemblance is clear.
Botanical Name: Cistus ladanifer
Cistus: Greek, kistos, applied to red-flowering shrubs
Ladanifer: Leaves exude ladanum, a fragrant resin
Common Name: Crimson-spot rockrose; gum rockrose
Family Name: Cistaceae
Origin: Mediterranean; Greece, Italy
Garden Themes: Mediterranean/dry, rock, coastal, cottage/informal, courtyard/patio (with room), pollinator, rain
Uses: Border, mass/drift, informal hedge, green stormwater infrastructure (elevated embankments & uplands only), accent, mass
The oleoresin is sweetish, which is why it is used to prepare sweets, food flavoring extracts and chewing gum. The oleoresin is also used to prepare essential oil used in the perfume and soap industries, and anti-aging traits are attributed to it.
Type: Evergreen shrub
Form: Mound, upright
Size: 5' tall by 5' wide
Outstanding Feature(s): Flower
Stem: Green-brown, tomentose
Color: Dark green above; light green to gray below
Surface: Glabrous above, pubescent underside; sticky to the touch
Flower: Spring to Summer. Showy, 5-petaled, white with maroon spot near center, prominent yellow stamens
Fruit: Autumn to Winter. Brown, 5-sided capsule
cultural requirements, tolerances & problems
Sunset Zones: 4-9, 14-24
USDA Zones: 9-11
WUCOLS SF Bay Area Hydro Zone: Low
Texture: Sand, rock
Moisture Retention: Well-drained
pH: Slightly acidic to alkaline
Tolerances: Drought, deer
Problems: May be short-lived with too much water once established
Branch Strength: Weak
Insects: Not recorded at time of posting
Disease: Powdery mildew
citations & attributions
Bayton, R. (2019). The Royal Horticultural Society's the Gardener's Botanical: An Encyclopedia of Latin Plant Names. London: Mitchell Beazley.
Breen, P. "Cistus ladanifer." Department of Horticulture, College of Agricultural Sciences, Oregon State University, Corvallis. Accessed on October 24, 2021, from https://landscapeplants.oregonstate.edu/plants/cistus-ladanifer.
Norris Brenzel, K. (Ed.). (2012). The New Sunset Western Garden Book. New York: Time Home Entertainment, Inc.
RHS. "Cistus ladanifer." Royal Horticulture Society, London. Accessed on October 24, 2021, from https://www.rhs.org.uk/plants/100349/i-cistus-ladanifer-i-l/details.
Water Use Classification of Landscape Species. "WUCOLS IV Plant List." University of California, Division of Agriculture and Natural Resources, Davis. Accessed on October 24, 2021.
Featured flower detail: "Cistus ladanifer" by Rhisiart Hincks is licensed under NonCommercial-ShareAlike 2.0 Generic (CC BY-NC-SA 2.0).
Fruit detail: "Cápsula de jara pringosa" by Rafael Medina is licensed under NonCommercial-NoDerivs 2.0 Generic (CC BY-NC-ND 2.0).
'Blanche' photo by TELCS.