I headed to VanDusen Gardens for inspiration on native ground cover plants that would be good for bumble bees. You don't even have to go inside the garden to find part of the Cascadia garden planted around the entrance with fabulous plants that fit the bill. This sedum is a good waterwise solution for a border plant.
There are lots of great kinds of sedum for bees. This one is blooming a lot earlier than the varieties I'm familiar with.
You can see hear how it will fill this border in nicely.
One of the EYA gardeners suggested Kinnikinik and I saw her eyes light up when she knew she'd hit on a great ground cover plant. The low growing berries are great for bees, including the native strawberries.
I have tried so many times to grow nodding onion from seed. Next year I'm just going to invest in the plants.
Wouldn't this be great in the meadow? And you can eat these onions!
This is a good variety of salal that appears to grow low to the ground. I believe the plants I've mentioned above should all be good for rooftop gardens as well.
In terms of higher plants, Hartley also mentioned snowberry, which does attract a lot of bees. My neighbor has one that is quite tall (4-6 ft) that grows along her fence under a fir tree.
Other taller native bee plants include aquilegia or columbines. You can plant the one that is native to BC and have fun planting the non native ones to see which pollinators are attracted to the blossoms. The same goes for the bleeding heart varieties. Solomon's seal, and native cranesbill geraniums are good too.
When in doubt, plant berries! Native blackberries do creep along the ground on the edge of the forest floor. Salmonberries and thimble berries are great native bee plants. The advantage of most of these plants is that they can also survive in dappled shade and some can even do well in the shadiest parts of your garden. You just have to experiment to see if they like the spot you choose for them. Sometimes it takes two or more years for native plants to really establish themselves, but it is so worth the extra time and trouble to see them flourish and feed the native bees.