Common Name: California Wild Rose

General Information

Rosa californica is a prickly, deciduous shrub producing at cluster of erect to ascending, densely to openly-branched stems that can grow around 80 - 250cm tall. The plant usually forms thickets[].
The plant is harvested from the wild for local use as a food, medicine and source of materials. It is occasionally grown on a garden scale for its fruits in the USA[], and is sometimes grown as an ornamental.

Known Hazards

There is a layer of hairs around the seeds just beneath the flesh of the fruit. These hairs can cause irritation to the mouth and digestive tract if ingested.

Botanical References

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Range

Western N. America - Oregon, California, Baja California Norte.

Habitat

Sunny streamsides, slough banks, mesic draws, moist areas in open woodlands, brushlands, and grasslands; at elevations up to 1,800 metres[].

Properties

Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Deciduous Shrub
Height	2.50 m
Pollinators	Insects, Self
Self-fertile	Yes
Cultivation Status	Cultivated, Ornamental, Wild

Cultivation Details

Rosa californica is a very cold-hardy plant, being able to tolerate temperatures down to around -25°c when fully dormant[].
Most Rosa species require a sunny position if they are to flourish and flower well. They prefer a circumneutral pH, succeeding in a range of soil texturess so long as they are moist but well-drained[, ].
The flowers have a rich perfume[].
The plant that is most commonly grown as an ornamental under this name is in fact Rosa nutcana[].
Rose species will often hybridize freely with other members of the genus[].
Plants in this genus are notably susceptible to honey fungus[].

Edible Uses

Fruit - raw or cooked[, , , ]. Eaten raw when it becomes soft after a frost, it is much esteemed[, ]. Rich in vitamins A and C[]. The scarlet, more or less ovoid, sometimes globose to obovoid fruit is around 10 -- 18mm × 7 - 20mm[], but there is only a thin layer of flesh surrounding the many seeds[]. Some care has to be taken when eating this fruit, see the notes above on known hazards.

The seed of roses is generally a good source of vitamin E, it can be ground and mixed with flour or added to other foods as a supplement. Be sure to remove the seed hairs.

The blossoms have been soaked in water to make a beverage[].

Medicinal

An infusion of the blossoms has been used as an analgesic and febrifuge in treating pain and fevers in infants[].

An infusion of the seeds has been used in the treatment of stomach fevers and painful congestion[].

A decoction of the fruit has been drunk in the treatment of kidney complaints, indigestion, rheumatism, sore throats, fevers and colds[].
A decoction of the fruit has been used as a wash on scabs and sores[].
The fruit of many members of this genus is a very rich source of vitamins and minerals, especially in vitamins A, C and E, flavanoids and other bio-active compounds. It is also a fairly good source of essential fatty acids, which is fairly unusual for a fruit. It is being investigated as a food that is capable of reducing the incidence of cancer and also as a means of halting or reversing the growth of cancers[].

Agroforestry Uses:

Rose species in general grow well with alliums, parsley, mignonette and lupins[, ]. Garlic planted nearby can help protect the plant from disease and insect predation[, ]. Roses often grow badly with boxwood[].

Other Uses

An essential oil is obtained from the flowers and leaves, it is used in perfumery[].

The unsplit stems have been used as rims in twined basketry[].

Propagation

Seed. Rose seed often takes two years to germinate. This is because it may need a warm spell of weather after a cold spell in order to mature the embryo and reduce the seedcoat[]. One possible way to reduce this time is to scarify the seed and then place it for 2 - 3 weeks in damp peat at a temperature of 27 - 32°c (by which time the seed should have imbibed). It is then kept at 3°c for the next 4 months by which time it should be starting to germinate[]. Alternatively, it is possible that seed harvested 'green' (when it is fully developed but before it has dried on the plant) and sown immediately will germinate in the late winter. This method has not as yet(1988) been fully tested[]. Seed sown as soon as it is ripe in a cold frame sometimes germinates in spring though it may take 18 months. Stored seed can be sown as early in the year as possible and stratified for 6 weeks at 5°c[]. It may take 2 years to germinate[]. Prick out the seedlings into individual pots when they are large enough to handle. Plant out in the summer if the plants are more than 25cm tall, otherwise grow on in a cold frame for the winter and plant out in late spring.
Cuttings of half-ripe wood with a heel, July in a shaded frame. Overwinter the plants in the frame and plant out in late spring[]. High percentage[].
Cuttings of mature wood of the current seasons growth. Select pencil thick shoots in early autumn that are about 20 - 25cm long and plant them in a sheltered position outdoors or in a cold frame[, ]. The cuttings can take 12 months to establish but a high percentage of them normally succeed[].
Division of suckers in the dormant season. Plant them out direct into their permanent positions.
Layering. Takes 12 months[].