Rosa californica

Paul (and anyone else), you’re welcome to peruse my directory of six local populations of Rosa californica. The titles of the folders are self-explanatory. Steer clear of the Arnold Arboretum specimen, which is undoubtedly mislabeled.

You’ll see that Rosa californica. almost always has falcate prickles. Also, Rosa californica. will bloom from May or June through September. The terminal inflorescences can have as many as 60 blooms. Foliage is rather rounder, shiny or matte, downy or smooth above, downy or glandular below. Hips comes in every kind of ovoid or round to slightly urn-shaped.

Rosa woodsii var. woodsii should have mostly straight, unequal prickles. My plant from Oregon also has noticeably dilated stipules. The foliage reads rather grey-blue compared to Rosa californica.

I can’t speak to R. nutkana. Every one I see in a botanical garden is different from every other. One day, after children are married off and some of the dogs have died, I’ll make a July roadtrip through the Mountain West to photograph species roses.

I’m also no help on R. woodsii ultramontana, except to note that in California, it is glandless according to the Jepson Manual bible.

Link: rosefog.us/SonomaSpecies/

Here in the Monterey Bay area, R. californica typically has dense straight prickles on the lower 1/3 of the stem, and sparse slightly curved prickles on the upper 1/3 of the stem. None of the other species native to California have curved prickles. It blooms from May to December here. The longer it blooms, the more hips there will be in each cluster. I’ve seen clusters of over 100 hips.

Cass,

After looking at your photos, I can say that I doubt that any of the specimens I have seen locally are R. californica. However, the Arnold Arboretum set you posted looks very much like specimens I have around here. Do you know what those are??

Also, I would say that about 1/3 of the local individuals have strongly pine or cedar scented foliage when rubbed. I wonder if I am looking at a body of R. nutkana and that it is just extremely variable and this scented foliage is just one of many traits that appears in some individuals and not others?

Also, I have taken some pics of what I have been calling R. woodsii fendleri and will post a gallery soon. This is a plant that was collected over a decade ago at the northern tip of the Tobermory peninsula in Ontario, Canada. Precise location on map should show as the south side of the Big Tub Road peninsula. Listing as a Zone 5a because of its proximity to the water, this is an inhospitable environment where Winter nights can often drop to minus 40F or colder. This rose grows happily in this climate without any signs of freeze damage. Thickets of it were also found to grow under a canopy of trees where it received no direct sunlight. See Maps URL:

Link: maps.google.com/maps/ms?hl=en&ie=UTF8&msa=0&msid=116404152025178677290.000467c7e4e1f804dce93&ll=45.257436,-81.673474&spn=0.003304,0.008218&z=18

Hi Fara,

Those are great crosses you made. I planted Henri Martin last spring and was disappointed by how much powdery mildew it had. One of the reasons I got it was because it had been so healthy at the Arboretum here, but apparently they don

‘Henri Martin’ only mildewed badly on the old leaves here in Australia (9b) and even this was only towards the middle of Autumn (now). The new growth is very strong and clean and it flowered for a very long time despite being non-remontant. It set OP hips well this year in a bed of DAs, minis, and hybrid multiflora so next season I’m hoping to see how it goes with more planned crosses… I actually want to try it with ‘The Fairy’ (but only because I want to make a mossed ‘The Fairy’ descendant so I can call it ‘The Hairy Fairy’ LOL).

Paul, when I have a second, I’ll check the accession numbers from the Arnold Arboretum against my photos of labels in their living plants collection. I have a vague recollection that the plant came from the Rancho Santa Ana Botanical Garden. There are a lot of suckering Section Cinnamomeae look alikes that make ID’s very tricky once they are removed from their native habitat. Compare that plant I photographed to Rosa davurica, and you’ll see what I mean.

By the way, I’m sure you know that collecting wild species and introducing them into your garden is something that should be done with great care, with a quarantine period being essential. I’ve seen 40 foot long stands of R. californica without one single hip. The most likely explanation for that is rose midge. I study plants for a couple of seasons before I collect. My personal favorites are those that are mowed to the ground annually and that roar back each year after their annual dose of herbicide.

Here’s the Arnold Arboretum accession record that corresponds to the label I photographed…assuming the label actually belongs to this rose…

Rosa californica Cham. & Schlechtd.

Accession Number: 1388-83

Accession Date: 28 Nov 1983

Wild collected in United States CA Ventura County

Locality: off Highway 33

Source: Santa Barbara Bot. Gdn., CA

Collection Date: Sep 1982

Living plants of this accession

Individual Plant - Location (grid) - Quadrant

MASS BRC-4

This was probably collected in the Los Padres National Forest, which is nearby. There’s a nice county mapping function on CalFllora.

In a brief telephone conversation with a biologist who has studied Rosa californica, she mentioned that Rosa californica probably has a relictual distribution - meaning that some ancient populations have become isolated and segregated by long term climate change, in this case warming and drying. Meanwhile, other populations survive in areas more akin to their preferred native habitat, like my climate where it survives easily in low lying areas.

Link: www.calflora.org/cgi-bin/occform.cgi?taxon=Rosa+californica&add_syn=t&county=Ventura&oform=html&out_map=t&action=t