Which Plant Would You Choose?

Among the plants we inherited from Mr. Previous Owner are some Agapanthus and a few Dietis (Fortnight Lily). We love the Agapanthus, but over time, I've started to tire of the Dietis just a bit. While the Agapanthus is popular with hummingbirds, the Dietis seems to have no wildlife value. It's also hard to keep under control, needing prompt removal of the seedpods and annual thinning. Finally, I'm not impressed how the strappy leaves of the Dietis contrast with the equally strappy (though less upright) leaves of the Agapanthus.

The challenge is deciding what to put in its place. And while I usually try to replace plants with California Natives, I might resort to something different this time.

Let me tell you about the location (above you can see the two plants from a different angle).

• Two plants on both sides of a little bridge.
• Currently about 4 feet high by 3 feet around, and I'd prefer not to go much higher because we want a view of the garden behind from the outside table. 
• Morning sun only September-March, more sun the rest of the year. (Redwood trees to the south).
• Acceptable colors: yellow, orange, white, rose but not pink. 
• Long bloom period in summer/fall preferred.
• Must tolerate low water condition (but will get some water during the dry season).

My first thought was Asclepias Tuberosa (photo above from Monarchwatch). I see one when walking downtown, the flowers more yellow than the photo. Similar to this photo from Wikipedia.

This butterfly weed is native to America but not California. It is drought tolerant, grows 24-36 inches. My big worry is that it seems to require full sun (though I've seen part sun listed in a few places). I'm also wondering whether this plant might get too big; the one I walk past is closer to 40 inches.

My next possibility is Sedum 'Autumn Joy' or once of its relatives. I have this plant already in two places in the garden, above in front of the bamboo fence -- a little more faded than Ms. Country Mouse's beautiful enclosure. Autumn Joy blooms at exactly the time when I'd like more going on in the Dietis spot, after the Agapanthus is done blooming.  I like the leaf shape, and won't mind that it goes dormant. But it, too, is happiest with full sun.

I've also considered a white rock rose (Cistus), and even some yarrow after cycling past some Moonbeam that was well over 3 feet tall just today. But I've had bad luck with Cistus, possibly drainage issues, and yarrow spreads a little too much for my taste.

So, dear readers, I'd love some input. When the rains start, I want to be ready to remove the Dietis and put in a beautiful wildlife plant that will cheer me in the dry doldrums of September and will attract bees and butterflies.