There is a huge bed of these near Upper Asian Way, mixed in with Rodgersia. I think they have opposite simple leaves around the size of the Rodgersia leaflets, nodding flowers a bit over 3cm in diameter with six rounded petals, lots of stamens, bisexual, white petioles, no fragrance apparent to me.
Ha-ha. I'm sure there is, under all those leaves. Thanks for the ID. I'm always relieved when I've never heard the name of something I post for ID, which is certainly the case this time.
Wikipedia says they have "relatively large "fishtail" leaves (cleft at the apex)." I see that I captured one in the first photo. It also says " Leaves are easily damaged in direct sun exposure", so it would seem a really good idea to have them covered by the Rodgersia leaves. Hydrangaceae.
Douglas Justice included this Deinanthe bifida in his October 2017 in the Garden | UBC Botanical Garden blog among a list of six Hydrangeaceae that will have to be renamed Hydrangea. For once, the new name will be easier to remember. We found this today by the fishtail (bifid, notched into two part) leaves. I don't know what the optimum time is to capture the fruits or what they ultimately will look like, but I seem to be the only person in the whole world who has photographed them, so these so far are optimum. The Missouri Botanical Garden page for this mentions that "deinanthe is an herbaceous perennial whereas hydrangea is a woody shrub or vine." Well, I guess we can't say that about Hydrangea any more.
It's so easy right now, white the Rodgersia are just getting going, to check out the leaves on what is still has the Deinanthe bifida label.