Website/Catalog  (2018)  
 
Rosa pisocarpa A. Gray, Proc. Amer. Acad. Arts. 8: 382. 1872.

Rosa pisocarpa A. Gray subsp. pisocarpa
Cluster or pea rose
Rosa rivalis Eastwood
Description

Website/Catalog  (2008)  
 
Check the New York Botanical Garden website for four outstanding large, pressed specimen of Rosa pisocarpa Gray.

Article (website)  (2007)  Includes photo(s).
 
Rosa pisocarpa A. Gray Cluster Rose
Subgenus Rosa, Section Cinnamomeae: A Thicket-Forming Rose
Lank shrub to thicket, 5-25 dm tall [20 inches to 8 feet]. Stem generally black; prickles few, generally paired at nodes, sometimes nearly lacking...; leaflets 2 - 3 per side, sparsely hairy to glabrous, leaf margins single toothed, generally glandless; inflorescence 2 - 10; blooming June to August. Generally moist or shady areas at forest edge; 30 - 2100 meter elevation.
North Coast Range and Klamath/Siskiyou Ranges of Northern California north on the west side of the Cascades to British Columbia.
Diploid.

Website/Catalog  (Jul 1998)  Page(s) 1.  
 
R. pisocarpa Species. ('The Clustered-Flowered Rose') Native to Menodcino County and many other parts of California, this rose produces clusters of small, single deep rose-pink blooms on upright suckering growth to 4-5'. In autumn the clusters of orange-red hips are quite showy.

Book  (1996)  Page(s) 189.  
 
Rosa pisocarpa Gray
Shrub 1-2 M tall, the stems armed with straight, slender infrastipular prickles, or sometimes unarmed. Leaflets 5-7, oblong to ovate, simply serrate, hairy beneat, without marginal glands. Petioles shot, hairy; stipules slightly glandular-toothed, hairy. Flowers 20-30 mm across, usually in terminal cluster. Fruit small, subglobose, dark red with short neck, 7-9 mm wide. Illustration. Can be distinguished from coastal R. nutkana var. nutkana, with which it may grow, by its simply serrate leaf margins. Those of R. nutkana in British Columbia nearly always display biserrate margins.
Range: Southern British Columbia to California west of the Coast and Cascade Ranges, in swamps and moist thickets.

Book  (Apr 1993)  Page(s) 511.  
 
R. pisocarpa Species, pink, description.

Website/Catalog  (1985)  Page(s) 42.  
 
Rosa pisocarpa* Flowers single. 1” diameter. Pink, in corymbs. Flowers June to August. P. F. (S) 4 x 3’. 

Book  (1981)  Page(s) 275.  
 
R. pisocarpa A. Gray. Shrub to 2 m./6.6 ft. high, branches slender, arching, sparsely prickly, more bristly at the base, prickles very small; leaflets 5-7, elliptic-oblong, 1-4 cm./0.4-1.6 in. long, coarsely serrate, puberulent beneath; flowers in corymbs with foliaceous stipules, purplish pink, to 3 cm./1.2 in. across, June-August; sepals glandular-hispid benetah; fruits globose, sometimes with short neck, orange, 8 mm./0.3 in. thick. 2n = 14, 21. WR 73. AFP 2510; HPN 3:172; GSR 36. W. N. America. 1882.

(1977)  Page(s) Vol. 8, no. 2, p. 15.  
 
HYBRIDISING WITH SPECIES 
By Franc Holliger
Of R. pisocarpa, I can quote from the book "The Complete Rosarian" by Norman Young, in which he says of a cross between R. pisocarpa (which is a graceful, upright shrub seven or eight feet high) and a dwarf polyantha, that it showed such moderate growth that he nearly threw it away; by the end of the first year it was still no more than two inches high, a matchstick with four leaves. But in the following year it went off with a bang, putting out four or five separate canes which reached a length of eighteen inches or two feet. Eventually it developed into a large bush, three feet high and nearly six across. He says that R. pisocarpa repeats sparingly but quite reliably. In my region it is a "ditch-dweller" and most attractive with a background of white fencing, this being "equestrian" country. (Diploid)

Book  (1954)  
 
[This statement refers to Harrison's own R. rivalis, not the American species]
At this point the topic of the puzzling rose described by Smith as Rosa rubella was raised. This species (?) was erected in 1810 on the basis of Durham material, and its status has ever since been a problem to rhodologists. By comparisons made point by point with Smith's and other descriptions, and by a direct consideration of Winch's specimens, the speaker showed that in every respect R. rubella agreed with certain segregates in the F2 R. sherardi x spinosissima lots, as did his own R. rivalis described from Wheel Birks plants. He had, therefore, no hesitation in regarding R. rubella and R. rivalis as naturally occurring hybrids originating in a cross between R. sherardi and R. spinosissima. Obviously, since F2 plants so reared are fertile, the generation to which they belong remains undecided. Professor Heslop Harrison stated that in his opinion, based on certain experimental data, they actually belonged to the F2 lot.