Article (newsletter)  (Apr 2022)  Page(s) 28.  
 
...Not at all inclined to rootspread, minutifolia sprouts wiry, thin canes that grow vertically then recurve strongly toward the ground. On reaching the sandy soil surface, the tip of the cane curves up again looking rather like a skinny snake looping along the ground. Where the cane touches the sand roots may sprout and another rosebush will grow and repeat the cycle. ...Blown about by wind, bark on the cane tip gets rubbed away by sand, and callus forms from which roots easily sprout. ...

Website/Catalog  (2018)  
 
Rosa minutifolia Engelmann, Bull. Torrey Bot. Club. 9: 97. 1882.
Ensenada or small-leaved rose
Hesperhodos minutifolius (Engelmann) Hurst
Decription

Newsletter  (Feb 2016)  Page(s) 7-8.  Includes photo(s).
 
[From "Rosa minutifolia--A Unique Rose Rediscovered", by Don Gers, pp. 6-12]
The Baja peninsula is a land of little rain. There, water is the currency of life especially evident in the towns: those with water were neat and thriving; without it they looked parched and poverty-stricken. At El Rosario the average annual rainfall is five inches. Just how little water that is amounts to about a quart per rosebush per week. Imagine what would happen to your roses if that's all the water they got! But R. minutifolia has learned to cope. The key to survival under the baking Baja sun is to be small and limit water loss. That is why minutifolia's leaves are so tiny (about the size of your smallest fingernail) and oddly constructed with wax-like surface, curled edge and felt lining. At the height of summer when drought is extreme, the bushes go deciduous, dropping leaves to become dormant, biding time till the rain returns, like a true xerophyte. After a good rain, the speed with which the rose can break into growth and bloom is amazing. In my Santa Rosa garden I've seen flower buds appear just fifteen days after the first big Fall rain and bloom three weeks later.
Another remarkable adaptation is its ability to bloom and set seed in the wintertime. In Baja this doesn't mean snow and freezing but merely less heat and more moisture. The ripening of its seed appears to be accelerated, too. On a mesa near Colonet in Baja, we found vigorous, blooming plants next to a leaking irrigation pipe with a few green hips. It was February but we collected the seed anyway and after planting, surprisingly they sprouted.
Hips were generally scarce. Searching numerous colonies we hardly found one or two hips per bush, yet the rose covered extensive areas, often one to several acres. But it didn't take long to discover minutifolia's method of propagation--I literally tripped over it. Not at all inclined to rootspread, R.minutifolia sprouts wiry, thin canes that grow vertically then recurve strongly toward the ground. On reaching the soil surface, the tip of the cane curves up again, looking rather like a skinny snake looping along the ground. Where the cane touches the sand, roots may sprout and another rosebush will grow and repeat the cycle. I observed that wind, sand and fog, constant elements of the Baja environment, assist this growth habit. Blown about by the wind, bark on the cane tip gets rubbed away by sand, and a callus forms from which roots readily sprout.

Newsletter  (Nov 2015)  
 
[From "Rosa minutifolia--A Unique Rose Rediscovered", by Don Gers, pp. 2-8]
Discovered over a hundred and thirty years ago, minutifolia is probably the rarest rose species in cultivation. I remember the first time I saw a plant at the University of California's Berkeley Botanic Garden shortly after it had been collected in Baja by a Staff expedition. It was a "wondrous strange" sight with incredibly tiny leaves and beautiful light magenta flowers. I decided then and there I must see this rose in its native surroundings. The day came in February of 1990 when my partner Michael and I drove our little '78 Colt packed to the ceiling with camping gear across the International Border at San Diego to Tijuana, a Mexican bordertown on the Baja peninsula....ose, I was beginning to despair. North of the town of San Vicente we came out of the hills onto a gently sloping mesa of cultivated fields . Between the fields and the highway was a deeply eroded gully with curious rounded shrubs growing along the edge. We stopped to have a look and spotted im mediately the tiny leaves and flowers of minutifolia! I could hardly believe my eyes. The rose grew about two and one half feet tall, and the colony here was fairly large with many dead bushes, I don't know why. I made a few notes and we drove on looking for more colonies. Just a couple of miles further we found the rose again, on a steep rocky sun-baked hillside only one to one and one-half feet high, growing with cactus and another shrub called Chamise, which it closely resembled, with similar bright green leaves, lax fountain-like growth habit and grey stem color. Growing side by side, only by its thorns could the rose be distinguished. The graceful Shaw's agave grew among the rocks with fishhook cactus, a pretty yellow-splined columnar cactus, euphorbias and prickly pear.

Book  (1993)  Page(s) 67.  Includes photo(s).
 
[Listed under "Wild Roses and Their Cultivars"] Dwarf rose. Description. From the dry mountains of Baja, California and now very rare in the wild. Flowers are produced from autumn to spring … spiny fruit. Height: 2 ft.

Article (magazine)  (1993)  Page(s) 35-36.  Includes photo(s).
 
The native stand of Rosa minutifolia in California is confined to a single quarter-acre plot in the southwest corner of San Diego County. There are more in Baja California [in Mexico]...All are under maritime influence with mild summers and nearly frost-free winters. ¶As is typical in Mediterranean climates, rainfall occurs in fall and winter months, generally from November through March. Even during this period precipitation can be spare, usually ten inches or less. Rosa minutifolia is, therefore xerophytic....Leafless in summer, it easily survives as long as nine months without water. When the rains come, it responds rapidly with growth, flowering, and setting seed. This winter-spring patterns of growth and bloom is possible because of the virtual absence of frost....A white-flowered variety is found only in Baja California....¶Rosa minutifolia is little known outside California....The oldest [garden] planting is probably in Rancho Santa Ana Botanical Gardens, where the former director...observed it for over twenty years. His three plants never produced seeds, so they concluded that they probably were one clone, grown from cuttings. This rose is known to be self-infertile, but seeds are produced readily in mixed stands.¶ Propagation methods include seeds (no stratification is needed), cuttings, division and layering. Tissue culture has not been successful to date. To my knowledge, hybrids have yet been produced....it is a diploid, so it would not hybridize with modern tetraploid cultivars.¶The distinctive characteristics described by Engelmann, along with the bast fibers in the tissue (known in only two other rose species), led to placement of this rose in a new subgenus of Rosa: Herperhodos. It was the sole species in this subgenus until the discovery in New Mexico in 1893 of Rosa stellata, whose strong affinity...indicate[s] a possible common ancestor.

Website/Catalog  (1982)  Includes photo(s).
 
https://scholarship.claremont.edu/cgi/viewcontent.cgi?article=1529&context=aliso

The Thorny Rose Affair: Discovery and Naming of Rosa minutifolia
Lee W. Lenz

Book  (1981)  Page(s) 295.  
 
R. minutifolia Engelm. Shrub 1 m./3.3 ft. high, young stems hairy, densely covered with slender, brown prickles, Leaves only 2-4 cm./0.8-1.6 in. long, with 3-5, rarely up to 7 leaflets, elliptic to obovate, 3-8 mm./0.1-0.3 in. long, deeply incised, hairy beneath; flowers solitary or several together, pink to nearly white, 2.5 cm./1 in. across, fruits globose, very prickly, red, 8 mm.(0.3 in. thick. 2n = 14. BC 3457. California. 1888. Needs dry, hot climate. Tender.

Book  (1981)  Page(s) 144.  
 
R. minutifolia Engelm. Hesperbodos minutifolia (Engelm.) Hurst
This species, a native of Lower California, is the senior member of the group [Rosa stellata and related species], discovered in 1882 and described in the same year. It was introduced to Kew in 1888 but did not long survive and is scarely likely to be hardy. It differs from R. stellata in its minute leaflets up to ⅛ to ¼ in. long, densely downy beneath, few-toothed, borne on a pale, downy, threadlike rachis. Young shoots downy, with numerous spines up to ⅜ in. long. Flowers 1 in. wide, pink or nearly white. Fruits globose, very spiny....

Book  (1976)  Page(s) 168.  
 
R. minutifolia Engelm.
- Bull. Torr. Bot. Club (1882), 9, 97
Büsche: bis 1 m hoch; junge Triebe behaart; Stacheln dicht gesät, bräunlich, fein.
Blätter: 3 bis 5 (7) Blättchen, nur 2 bis 4 cm lanfg; Blättchen elliptisch bis umgekehrt eiförmig, 3 bis 8 mm lang, tief eingeschnitten. Unterseite behaart.
Blüten: einzelständig oder viele zusammen, 2,5 cm breit, rosa bis fast weiss.
Früchte: rund, 0,8 cm breit; dicht borstig, rot. Blüte im Mai/August.
Verbreitet in Kalifornien, seit 1910 kultiviert; wächst im trockenem Klima, in Mitteleuropa winterhart.