Ground Effects Nursery here in the Lower Mainland has two species of the Ceanothus ground covers, C. gloriosus and C. griseus. http://www.groundeffectsnursery.com/pig-c.htm (Scroll down to Ceanothus) Does anyone have experience with this plant in the Lower Mainland? How do you think it might do in shallow, well drained, soil?
You will have to protect it as it is not fully hardy. Pick a sunny spot against a wall and protected from the wind. Expect some winter damage and if it is a concrete wall you plant it in front of mix in some peat moss during planting as the lime leaching off the wall could affect pH. Mabye even go so far as to Litmus paper the soil check pH
So are the people at Ground Effects embellishing the truth of its hardiness, to help sales? Not that I don't trust you, just curious why it would say C. gloriosus is hardy to -18c and C. griseus is hardy to -12c on their catalog?
I think it's kind of hard to put exact numbers on cold hardiness. There will be a range of temps tolerated depending on other conditions. Plants growing in California are going to get the benefit of warm (hot) dry summers. Plants growing in BC will experience cooler summers and wetter conditions. They may not grow as vigorously as the plants in their native environment and might succumb to the cold at temperatures a few degrees higher than the CA plants. Nurseries will choose the most appealing numbers from the range. I know that many people lamented the loss of their Ceanothus in the Lower Mainland in recent winters. I have some on the Sunshine Coast, which were damaged, though not killed by last winter's weather. Here is an interesting study of various Ceanothus cultivars at Oregon State. (They did not look at C. griseus.) Interesting to note the advice not to water the plants. [edited by wcutler: I have replaced the link, which was no longer working. I hope this is the same] Ceanothus Evaluation for Landscapes in Western Oregon | College of Agricultural Sciences | Oregon State University
Few kinds last indefinitely in plantings this far north. Hot and lean conditions produce the best results, do not mix peat into the planting area! Water for the first year or so until establishment is assured. Mulching with stones probably a good idea.
