The Somewhat Definitive Guide to Local Ceanothus

What better way to start off your day than with a dose of oxymoron.  For years the identification of our local ceanothus (no it’s not ceanothuses or ceanothi) has driven me literally batty.  Queries to local experts were of limited benefit.  My favorite online references also failed, seemingly mocking my exasperation.  Well as my great uncle Ignatius used to say, if you want something done right, you’ve got to do it yourself.

OK so believe it or not we have six (6!) local ceanothus.  If you call it California Lilac you are banned from the blog for one month.

Let’s get the rare (for down here) one out the way first.  Ceanothus leucodermis, or White thorn ceanothus:

White thorn

White thorn

Generally found only at elevation.  Aside from a stray on Matilija (just before the first stream crossing) and a couple up Sisar, this one is very common on Howard Creek, and downright ubiquitous on Potrero John.  The flowers can be anywhere in the violet to purple range, and the branches… you guessed it.. whitish and pointy sharp.  Late bloomers too, generally May.

That leaves 5.  Let’s do the easy ones.  Ceanothus spinosus is very common round these parts, can even be found by the coast.

Green bark, violet flowers

Green bark, violet flowers

The new and young bark is quite green, turning brown as it ages.  As the species name implies, the branches that hold the inflorescences can be quite spiny.  The flowers are a very light lavender.  The leaves are shiny green and alternate, generally ovate.

Alternate leaves, spines

Alternate leaves, spines

You can find them on literally any local trail.  Cozy Dell and Kennedy Ridge are dominated by Green Bark.

Next up is my all-time favorite local, Ceanothus oliganthus, or hairy ceanothus.

Hills of purple

Hills of purple

Lovers of part shade and canyon areas, the rich vibrant purple is starting to light up our hillsides.  Best spots for these beauties are Rice Canyon and Chaparral Crest trails at the Ventura River Preserve, up Gridley in the shady areas near the trough and Matilija Canyon.  The leaves of oliganthus are dark, shiny, distinctly veined and most importantly SOFT.

Shiny soft, veined leaves

Shiny soft, veined leaves

Unlike the other ceanothus and most evergreen shrubs in our area who sport tough, stiff leaves to survive the long dry summers, hairy ceanothus has malleable leaves in an alternate arrangement, slight fuzzy on the underside.

Finally to my bugaboo, the white flowered ceanothus.  There’s three of them and differentiating them would bring me to tears at one point.  But no more.

Ceanothus megacarpus or big pod ceanothus has darn big seed pods, the biggest of the six, but that’s only helpful a few months a year until they fall off.

Alternate leaves, big pods

Alternate leaves, big pods

The key to identifying these the rest of the year is the alternate leaf arrangement.  The final two white-flowered ceanothus both have opposite leaves.  These are currently putting on a spectacular show along Route 150 to Santa Barbara, up Laguna Ridge, and there are quite a few up Pratt Trail.

Megacarpus up Laguna, note the large pod receptacles

Megacarpus up Laguna, note the large pod receptacles

That leaves us with the final two white flowered, opposite-leaved ceanothus.  Crassifolius, or hoary-leaved ceanothus is found on the Ventura River Preserve on the parking lot side of the river, up Gridley, Horn Canyon, and some up Pratt.

Notice the toothed leaves

Notice the toothed leaves

The leaves are opposite-arranged, with distinctive small teeth while otherwise large and ovate shaped.  The undersides are “hoary”, as in very whitish or frosted looking.

Opposite arranged leaves

Opposite arranged leaves

Last but not least is Ceanothus cuneatus, or buckbrush.

Wedge-shaped leaves, opposite arrangement

Wedge-shaped leaves, opposite arrangement

Also with opposite-arranged leaves these are much smaller than crassifolius, and “wedge-shaped” as this ceanothus is also known.  They are currently in bloom all over the Ventura River Preserve on the OTHER side of the river.   East side of river, crassifolius, west side, cuneatus, no strays as far as I know, pretty interesting I think.  I believe there are some on the Thacher trails as well.

Cuneatus on Chaparral Crest looking towards the river

Cuneatus on Chaparral Crest looking towards the river

OK let’s summarize

NAME                BLOOM COLOR        LEAVES       LOCATION

Leucodermis          Lavender                 Alternate      Potrero John

Spinosus                 Light lavender         Alternate        Kennedy ridge

Oliganthus              Purple                      Alternate     Matilija,Rice,Sisar

Megacarpus            White                       Alternate      Laguna, Rte 150

Crassifolius              White                      Opposite       Gridley, Horn

Cuneatus                  White                      Opposite       Wills Canyon

Would love to hear comments, questions, disputes, insults regarding this list… I know we have subspecies of some of these, but did I miss anything entirely?

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11 Responses to The Somewhat Definitive Guide to Local Ceanothus

  1. Brian says:

    Nice work Ron.

  2. Great to have this comparative guide, in that you surpass Jepson and everyone else for clarity and usability for this ultimately confusing species. Would appreciate seeing the whitethorn leaves along with the flowers.

  3. Also, not at all to embarrass but wartleaf ceanothus is missing which is found on the Camino Cielo Trail, southfacing slopes in the Santa Ynez Mountains.

  4. So helpful and passionate about our local chars para ecosystem, thank you for sharing your knowledge!

  5. Todd says:

    This is a good list Ron – for anyone who learns these five, any anomalies will jump out at them.

    In the Jepson, Ceanothus seem to be broken into two categories: those having knob-like stipules (once referred to as Cerastes, meaning horn-like), and those having scale-like stipules. You can find the stipules at the base of each leaf. The knob-like stipules are associated with more desert-like plants.

    For most of what we see in the Ojai Valley, the Ceanothus with knob-like stipules are pretty much all opposite-leaved, except for megacarpus (big pod), which has alternate leaves.

    Sometimes the subspecies can appear really different, so it is important to take them into account. For example Ceanothus crassifolius var. planus has flat leaves, and var. crassifolius has leaves that curl under. Both varieties have the same common name: hoary leaf.

    knob-like: alternate = C. megacarpus (big pod)
    opposite = C. crassifolius var crassifolius (hoary leaf)
    C. crassifolius var. planus (hoary leaf)
    C. cuneatus var. cuneatus (buckbrush)

    scale-like: All alternate leaves
    C. spinosa (green bark)
    C. oliganthus (hairy)

  6. JohnK says:

    I barely have time for my own children. To adopt more children and not have time for them, that would be poor parenting on my part. (c)Mary J. Blige life quotes

  7. Nancy Eldblom says:

    Being a list-person, I just had to check David Magney’s lists on the CNPS-CI chapter website. He includes 2 varieties of the wartleaf C. (C. papilosus) on his “Plants of Matilija Canyon” list.
    By the way, he now seems to have added a “Ventura County Flora” list there too. Note “Plant Checklists” there.

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