This member of the family Rhamnaceae, which goes by the common names Oregon tea tree, redstem ceanothus, redstem wild lilac, redstem buckbrush, northern buckbrush, and soapbloom, was a complete mystery to me when I found it on Memorial Day weekend, and I didn’t even know where to start looking for it. So I ended up plugging edited and cropped photos of it into the Seek by iNaturalist app (which, if I haven’t made this clear before, is an excellent and free identification app that I highly recommend to any budding recreational naturalists out there), which got me to Ceanothus , and then C. sanguineus.
When I compared my photos to images and descriptions I found in my books and online it seemed like a good fit, but as I mentioned in ‘A Trip to Canyon Creek , it was one of the plants I needed to confirm an identification for on my subsequent trip up there, because even the best identification apps are not flawless, and I hadn’t gotten good photos of the stipules, so I couldn’t rule out C. velutinus (I was able to rule out C. integerrimus because it has unserrated leaves). Unfortunately, due to a focusing error I still don’t quite understand, I again failed to get good photos of the stipules, but by blowing up the photo below I believe you can see that these stipules are clearly greater than 3mm, rather than the 1mm stips of C. velutinus.
I don’t know if this shrub is uncommon, or whether I’d just missed seeing it in bloom, or whether it is yet another case of me walking repeatedly by, in a tunnel visioned haze while looking for something ‘more interesting’, a plant that is, based on the number of creatures I found that eat it, an important part of any ecosystem in which it occurs. It’s kind of a messy looking shrub, with stems and branches going every which way, but it has beautiful panicles of white flowers that have a very pleasant fragrance. I’ll certainly be keeping my eyes more open for Ceanothus sanguineus from now on!
Ethnobotany– “Poultice of dried, powdered bark applied to burns…Wood used for fuel…Wood used to smoke deer meat…Poultice of ‘sap wood’ sprinkled on grease or oil applied to sores or wounds.” BRIT – Native American Ethnobotany Database; “A tea has been made from the leaves; a poultice of the dried, powdered bark has been applied to burns, sores and wounds; and a green dye was made from the flowers. It was called “Soapbloom” because all parts of the plant contains saponin, and was mixed with water and beaten into a soapy foam. The foam is good for cleaning dirt but does not remove oil; so it will not dry skin. The flowers, especially, were nice for use as a body soap because of their pleasant perfume. Natives burned the wood for fuel and to smoke deer meat.” Red Stem Ceanothus, Ceanothus sanguineus | Native Plants PNW
Description– “3-10 feet [tall]…Erect shrub. Stems green when new, becoming red to purple. Leaves deciduous, alternate, petiole less than 1 in., blade thin, widely oval with pointed tip, tiny teeth. Flowers white on red stalks at tips on stems, cluster less than 5 in. long, very fragrant.” Ceanothus sanguineus | Redstem Ceanothus | Wildflowers of the Pacific Northwest
Similar species–Ceanothus velutinus has stipules only 1mm long, and leaves that are glossy on the dorsal surface; C. integerrimus has smooth, unserrated leaf margins; other Ceanothus in our region have opposite leaves or blue flowers.
Habitat– “This species grows in dry open sites and forest edges, often in recently burned areas. Wetland designation: It almost always occurs in non-wetlands areas in our region.” Red Stem Ceanothus, Ceanothus sanguineus | Native Plants PNW
Range– “This species is native on both sides of the Cascades from British Columbia to northern California; eastward to western Montana, with reported occurrences in South Dakota and on the shores of Lake Superior in Michigan (Listed as threatened in Michigan).” Red Stem Ceanothus, Ceanothus sanguineus | Native Plants PNW ; found almost region wide in the PNW, except absent in shrub steppe, high elevations, and west of the Coast Range
Eaten by– “Redstem Ceanothus is a favorite browse species of elk and deer as are other Buckbrushes. Snowshoe Hares also eat the foliage and rodents eat the seedlings. Birds, rodents, ants, and other insects consume large amounts of the seeds. The shrub provides good cover for birds and small mammals. Flowers are pollinated by bees. Ceanothus sanguineus is a larval host for the Pale Swallowtail Butterfly.” Red Stem Ceanothus, Ceanothus sanguineus | Native Plants PNW
“Foodplant for Pale Swallowtail, California Tortoiseshell, and Hedgerow Hairstreak. Gelechiidae: Chionodes ceanothiella. Gelechia monella. Geometridae: Common Gray (Anavitrinella pampinaria). Drepanulatrix falcataria. Yellow-banded Looper (Drepanulatrix foeminaria). Blotch-lined Looper (Drepanulatrix secundaria). Eudrepanulatrix rectifascia. Eupithecia misturata. Hesperumia latipennis. Sulphur Wave (Hesperumia sulphuraria). Darwin’s Green (Nemoria darwiniata). Brown-lined Looper (Neoalcis californiaria). Rindge’s Pero (Pero mizon). Bordered Fawn (Sericosema juturnaria). Sericosema wilsonensis. Noctuidae: Abagrotis apposita. Rusty Shoulder Knot (Aseptis binotata). Saturniidae: Ceanothus Silkmoth (Hyalophora euryalus). Western Sheepmoth (Hemileuca eglanterina).” https://www.cnps-scv.org/images/handouts/CaliforniaPlantsforLepidoptera2014.pdf
Charley Eiseman (Leafminers of North America – 2nd Edition – ©2021) lists the leaf mining larvae of the moths Stigmella ceanothi, Lyonetia prunifoliella, Tischeria ambigua, and Marmara spp. as using this plant; Clark/Ledoux, et al (2004) list the leaf beetles Altica prasina, Brachycoryna hardyi, and Scelolyperus varipes as having been found on these plants, and though that is no guarantee that either the adults or larvae eat them, Eiseman also records Brachycoryna hardyi mines on C. sanguineus; I find several members of Pentatomidae listed for other Ceanothus, but nothing specific to this species.
Reproductive timing– “Bloom time: May-July; Capsules ripen: June-August.” Red Stem Ceanothus, Ceanothus sanguineus | Native Plants PNW
Etymology of names– Ceanothus is from “Greek keanothus, name used by Dioscorides for some spiny plant” Ceanothus in Flora of North America @ efloras.org. The specific epithet sanguineus is from Latin and “means blood red, referring to the stems or flower stalks” Red Stem Ceanothus, Ceanothus sanguineus | Native Plants PNW