I have a hard time keeping these two straight. Which one fills in and covers an area the best?
I hate to say it since I'm such a fan of Arctostaphylos, but I'd say Cotoneaster is probably more versatile over all. Too much has the potential to go wrong with kinnikkinnik. 'Massachusetts' tends to suffer if it gets too hot and dry... other varieties can have problems with dead patches if they get too wet. Cotoneaster is a bit more shade tolerant as well. Now if it is a dry, sunny site and you can find Arctostaphylos 'Point Reyes' or 'Pacific Mist', either of those would be a good choice.
I agree with Ian - cotoneaster spreads faster and can offer a much denser cover than kinnikinnick. Better weed control that way :-) Also tends to be a bit flashier in flower and with more pronounced berrying. In fact, the cotoneaster can be towards the more invasive scale of the spectrum although dammeri tends to be less of an issue than other species.
Bearberry is pretty consistent about turning black, even before it gets out of the garden center. Most would find the cotoneaster much more handsome and satisfactory. That said, the Arctostaphylos can be quite nice in the right spot - like a fully exposed, sandy bank. And 'Massachusetts' is supposed to resist the blackening. However, I'm beginning to think the local trade has this one mixed up, as I see stock that does not fit the bill - it should have noticeably small, dark leaves.
And, I guess, not be going black right in the pot.
The typical natural situation for bearberry is a hot spot in a cool climate. Most other manzanitas grow in hot spots in hot climates, if you want to keep them doing well here you have to give them a planting site that bakes. But with the same loose, well-aerated soil that rhododendrons and other heath family plants want - one time I pulled off the road to look at some hairy manzanita and then walked up onto a hillside behind, where recent clearing for housing had made it into a seed bed for nearby shrubs. Hundreds of coast rhododendron and hairy manzanita had come up near one another.
Cotoneaster on the other hand don't seem to be so soil specific, and in fact tend to appear to be quite suited to heavy ones. Dozens of species have been observed coming up from seed, on their own in Seattle.
This post was edited by bboy on Mon, Apr 29, 13 at 19:54
Most manzanitas chemically inhibit weed growth, but I'm not sure if that includes all of the A. uva-ursi varieties. Overall, cotoneaster is going to be less fussy with soil and lighting conditions.
I picked up a 'Massachusetts' A. uva-ursi as an impulse buy at a local nursery, and have been very impressed with it. It can take a beating (transplanted it four times during its first year) and is a nice plant in partial sun next to a once-a-week watered lawn, provided that the top of the root ball is up an inch or so from the lawn. (And don't go overboard on the watering.)
In addition to the aforementioned 'Point Reyes' and 'Pacific Mist,' 'Mound San Bruno' and 'Carmel Sur' will work as well. (The latter grows fast, but spreads quite a bit.) If you want something taller, 'Wayside' and 'Martha Ewan' will tolerate clay and some summer water, provided that drainage is decent.
This post was edited by OregonGrape on Mon, Apr 29, 13 at 18:35