Rosa minutifolia
San Diego's Wild Rose-- R. minutifolia



Written by Ivy Bodin for CCRS in Spring 1999

Photograph by Ivy Bodin

It stands on the edge of a riparian woodland area in a gaggle of dried bristly branches over an area measuring 6 feet by 4 feet, neatly secluded in the Kupanda Falls Botanical Center, California Nativescapes Botanical Garden of the San Diego Wild Animal Park in Escondido, California. The botanical sign identifies it as small-leaved rose, Rosa minutifolia, characteristic of San Diego County and the Baja.

It has been called the botanist's rose, the xerophytic rose, the small-leaved rose, the high desert California rose, the wild Baja California rose. Once in San Diego county there were stands of the species rose in the wild. Rosa minutifolia is now rare in the wild in the U. S. as currently reported by Southern California native plant specialists. Reiser noted in 1994 its only known U. S. occurence was on Otay Mesa in San Diego County and that was jeopardized by recreational usage of the terrain.

In 1994 Reiser characterized the rose to be a C2 Federal Candidate for listing as an endangered species and it was listed as a CE California endangered species which was in serious danger of becoming extinct throughout all or a significant portion of its range. California Native Plant Society R-E-D code show it as a List 2: with plants rare or endangered in California, but more common elsewhere. State ranking is S1.1 which equals very threatened. A current Listing of Plants of California declares Rosa minutifolia to be endangered, threatened or rare, 670.2. http// www.dfg.CA.gov/Title/d3--html-- May 8, 1999.

In the 1990's Quail Botanical Gardens in Encinitas, California was named the germ plasm repository by the USDA for Rosa minutifolia and recent contact with the horticulturist at the garden indicated this status would soon be currently updated. The garden has small stands of the rose growing in several locations. The only other official showing of the species variety is in the garden of the San Diego Wild Animal Park maintained by the Lake Hodges Native Plant Club, Inc. Mention has been made of the Santa Ana Botanical Garden growing the rose in past years, as well as Tree of Life Nursery in San Juan Capistrano. Plant enthusiasts at Quail Gardens and the Wild Animal Park hope to propagate the species variety for further dissemination but the rose is known to be difficult to propagate from cuttings and only the species variation from Baja sets seed which are viable. The variety from Otay Mesa does not set seed. The rose also is in cultivation currently in a few private gardens in San Diego County and the area.

The Herbarium of the San Diego Natural History Museum in Balboa Park on a recent visit currently had 31 dried specimens of Rosa minutifolia on file for viewing. The first and oldest specimen of theirs was collected from Baja in January 1883, a part of the Cleveland Collection initiated when the natural history museum was founded. Other specimens of the rose date from 1938-1980, etc. with the first California specimen collected by Jack Reveal in 1985 after discovery by Royce Riggan in 1984 on Otay Mesa, San Diego County.

Reference to the article of 1993 by Lawrence Smith in Pacific Horticulture shows a California stand of the rose was first discovered in 1985 by Jack Reveal, a botanist. Rosa minutifolia had been first discovered by Dr. C. C. Parry in 1882 in Baja California and he recognized it as a new and distinct species and sent material to a Dr. Engelmann in St. Louis for evaluation. Engelmann noted "this was a most striking and lovely species, distinguished from all other roses by its minute, deeply incised leaflets."

A fairly thorough recent review of the available rose literature produced only three slight references to the rose's existence: Modern Roses 10 of 1993, Rix and Phillip's quote and photo in their The Quest for the Rose of 1993, and an article on species roses edited by Bunny Skran for the American Rose magazine of May 1996. Most of all references to the rose otherwise are found in the literature on California native scape and species plants. Wiggins in 1980 described it and illustrated with a drawing. Jepson's Guide to California Native Plants and Species, the bible of nativescapes, was first published in 1923 but did not list the rose. Again in the 1951 and 1970 editions no mention was made of Rosa minutifolia with its first listing in Jepson being in their revision of 1993. Modern Roses I of 1930 does not list the rose. Modern Roses II of 1940 lists it and Rosa minutifolia thereafter appears in all issues of Modern Roses II-X inclusive. (1940-1993)

THE BOTANIST'S ROSE

Englemann's description of Rosa minutifolia as quoted by Parry in Smith's 1993 article is typical of the care required to distinguish plants that are superficially similar. This rose is described as follows: A much branched shrub, two to four feet high, shoots pubsescent, densely covered with straight or slightly recurved red-brown spines. The leaves have broad, divaricately auriculed stipules and mostly five leaflets.

Fertile branches bear numerous terete subulate spines, some of the more persistent ones often in pairs under the branchlets. Leaves fasisculated on short spurs, arrow stipules divaricately auricled. Leaflet minute(only one to two lines(one-twelfth to one-sixth inch) long, the lowest pairs the smallest), oval, simply incised dentate, pubescent, not glandular. Flowers single, three-quarters to one inch wide on tomentose, bractless peduncles from between the leaves. Calyx-tube globular, densely setose-hispid, a thick nectariferous ring contracting its opening. Petals suboricular, scarcely emarginate, deep rose-purple or white. Central ovules borne on short stipes; styles distinct, short, woolly.

Rosa minutifolia grows under the maritime influence of the local Southern California climate with mild summers and nearly frost-free winters and in this respect is a typical member of the coastal sage scrub. Leafless in summer, it easily survives as long as nine months without water. It responds rapidly to the sudden rains and sets flowers and seeds. It is known as the xerophytic rose because it sheds its leaves during the summer months when rain fall is non-existent and water is thus conserved by the plant. Newly blossomed leaves begin to appear in the fall usually with the first rains of October. Slowly the individual leaves, less than a quarter inch long begin to sprout and occasionally a fuschia-colored one inch bloom of 5 petals with prominent yellow staments appears sporadically. As the season progresses, many more blooms cover the branches. Pink and white colored blooms have also been reported in the species.

The last major wild stand of the rose located on Otay Mesa in San Diego County was reported as being observed on several field trips by plant specialists in the 1980s and 1990s and that this last great wild stand of plant material was removed about two years ago to further urban development. At the time of a visit a botanist on one field trip was overheard estimating the virgin growth pattern of the wild rose, covering a canyon in an area of about 100 square feet, as a 500 year old undisturbed growth specimen. That wild stand exists no more. Currently plant enthusiasts report of only seeing Rosa minutifolia growing in great wild swatches south of Ensenada in the Baja. This is evident as the rose fleshes out many small fuschia-colored blooms on the hillsides in the winter and early spring with the arrival of the rains. The roses' habitat even on the Baja is threatened, however, now with further urban development on the peninsula.

As with most southern rose species, Rosa minutifolia is a diploid, and so would not hybridize with modern tetraploid cultivars. Englemann placed this rose in a new subgenus based on the bast fibers in the tissue(known in only two other rose species), Rosa: Hesperhodos. It was the sole species in this subgenus until the discovery in New Mexico in 1893 of Rosa stellata, whose strong affinity with R. minutifolia(including base fibers in the tissue), small leaves and drought resistance indicate a possible common ancestor. This rare rose is now on the California Endangered Species list.

BIBLIOGRAPHY

Rare Plants of San Diego County. Craig H. Reiser. May 1994.

The Jepson Manual of Higher Plants of California, edited by James C. Hickman, 1993. University of California Press, Berkeley & Los Angeles, California, pp. 498-499.

A Manual of the Flora of California, by Wilis Linn Jepson, 1923, copyrights also in 1951 and 1970.

Flora of Baja California. Ira L. Wiggins, 1980. Stanford University Press, pp. 798-799.

"The Xerophytic Rose", by Lawrence Smith, PACIFIC HORTICULTURE, Vol. 54. No. 1, Spring 1993. George Waters, Editor, p. 35.

"A New North American Rose", by C. C. Parry, BULLETIN of the TORREY BOTANICAL CLUB, VOL. IX, No. 8, August 1882, New York. pp. 97-98.

MADRONO. A WEST AMERICAN JOURNAL of BOTANY, April 1986, VOL.33, No. 2, p. 150. "R. Minutifolia"

ANNALS OF THE MISSOURI BOTANICAL GARDEN. May 1965. Vol. LII, No. 2. MONOGRAPH 4 of ROSA IN NORTH AMERICA. V. SUBGENUS HESPERHODOS.

The Herbarium. San Diego Museum of Natural History.

MODERN ROSES I-X dated 1930-1993.

Combined Rose List. 1994. Peter Schneider and Beverly R. Dobson.

Handbook for Selecting Roses. American Rose Society, 1994-1999.

The Quest for the Rose. Roger Phillips and Martyn Rix, cc 1993. Random House Inc., New York, p. 67.

"Species and Their Exhibition", by Scott Hansen, Steve Jones, Bunny Skran, writer and compiler. The American Rose Magazine, May 1996, p. 19.

INTERVIEWS WITH

Bill Grant
Pat Sigg
James Dillane
Don Miller
Fay Schopp
Timothy Phillips
Judy Gibson

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