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Saturday - July 27, 2013

From: San Diego, CA
Region: California
Topic: Propagation, Seeds and Seeding, Shrubs
Title: Weak flowering on rosa minutifolia from San Diego CA
Answered by: Barbara Medford


Hi, I have a Rosa minutifolia and has been doing great, but when it gives flowers the petals fall too fast, only last a day or two and also the fruit never forms completely and finishes drying so I can't get seeds. What can I do? The plant receives indirect light the most of the day, and 3 hours of direct light approximately. It is not under typical water-stress of the summer, I water it regularly to keep it out of dormancy. Thanks for the advice


From Calflora, here is Taxon Information on Rosa minutifolia. According to this USDA Plant Profile Map, it is native only to San Diego County in North America. Although the USDA is our source for material in our Native Plant Database, the map is all we can find in the USDA database, no information on whether it is native or introduced, etc. So, we have nothing in our database on it. We do know from the Taxon Information (above) that it is considered endangered, but not whether it is officially classified as native to North America. The best information we found on the plant was in the Las Pilitas Nursery website.

From the Las Pilitas Home Page:

"Since the 1970's Las Pilitas Nursery has been combining research and California native plants. We do the work, you get to play with the plants and enjoy the resulting web pages."

So, we will accept their word that this is a native plant to North America, but so far we still have found no information on growing conditions that might give us a clue to the answer to your question. The California Coastal Rose Society has a long article on it, but it infers more that the plant is disappearing altogether than that it has trouble retaining  blooms long enough to seed.

From helpmefind.com on 'Rosa minutifolia Englemann':

"USDA zone 9b and warmer.  Can be used for specimen.  Benefits from winter protection in colder climates.  drought resistant.  prefers dry climates.  prefers full sun.  prefers warmer sites.  Do not prune."

Perhaps it is getting too much water and not enough sun, both of which can inhibit blooming in a rosa genus. Be sure and not sprinkle the leaves to water, as this is conducive to mildew, which could also be causing petal drop.



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