ground cover plants and question about Meeting in Berkeley

Jane McGary
Fri, 13 Apr 2012 11:48:48 PDT
Elaine wrote,
>I'm new to PBS. I'm located in Silicon Valley, CA area. I'm growing 
>summer growing bulbs like cannas, tulip, kniphofia, watsonia, 
>amercrinium and some winter ones like galanthus, bletilla 
>striata(not sure if this orchid is considered a bulb). I'm wondering 
>what are good ground cover plants that remain evergreen or 
>preferably bright green(not dull algae green) through the mild 
>winters here. I've started on some achillea millefolium 'Sonoma 
>Coast' and low growing manzanitas I got from Yuerba Buena Nursery. I 
>water once or twice a week in summer. Are there drought tolerant 
>plants that can do well (in SF Bay south peninsula area) to cover 
>over the bare ground while the summer bulbs are dormant besides 
>vinca or ice plant?

I'd not recommend Achillea, because it forms a dense, semi-woody 
crown through which smaller bulbs couldn't emerge. The same would be 
true of the South African composites often used as ground covers in 
your area. The low-growing manzanitas (Arctostaphylos spp.) are good 
companions for winter-growing bulbs, but in the summer you will have 
to water your cannas, bletillas, and other summer-growers, and this 
may kill the manzanitas (root rot). Hebes would be a better choice 
for a summer-irrigated area. and there are dozens of kinds available 
in your garden centers, including very low-growing ones. If you have 
room, I'd set aside one part of the garden for the big bulbs you 
mention and another for the manzanitas, prostrate ceanothus, 
prostrate dwarf pines, and winter-growing bulbs, including Pacific 
Coast natives. If you use evergreen shrubs judiciously, you can make 
appropriate habitat areas even in a small garden. For instance, I 
have one small bed largely planted to the summer-growing, 
moisture-requiring bulb genus Eucomis, preceded in spring by 
trilliums and primulas and eventually to be "carpeted" with small 
Epimedium varieties, punctuated with some Heuchera varieties; and 
another area on top of a dry bank that is a "chaparral" with 
Arctostaphylos, Cistus, Ceanothus, small species bearded irises, and 
larger bulbs such as Brodiaea californica, just mulched with grit.

Thymes are good drought-resistant ground covers for small bulbs, but 
they couldn't coexist with the large subtropical subjects you 
mention. If you want something flowering in winter in between your 
cannas and crinums, there are also winter-growing annuals (e.g., the 
annual lupines native to your area), many of them native to the 
Pacific Coast, that can just be pulled out after they flower in 
spring. Check out the website of the Theodore Payne Foundation for 
seeds. Vinca and "ice plant" (a vigorous succulent, not sure what 
it's called now but it used to be Mesembryanthemum) should not be 
planted because they are listed noxious weeds.

Jane McGary
Portland, Oregon -- but originally from San Francisco 

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