These plants any good?

[Gardenpro]

Like many of you my hives are a little light right now. I have no idea where my bees are foraging currently.
Blooming in neighbouring fields:
Hardhack (Spirea douglasii)
Knotweed (Polygonum)
Small amount of white clover
Aster (several different purple species)
Yarrow (Achillea millefolium)

Besides the clover, do the others look any good?

[louis1st]

I know aster is good but not sure about the other ones...

[George Fergusson]

Japanese knotweed is an awesome bee plant, and a highly invasive species. I wish I had some growing near (but not on) my property. It blooms for quite a while late in the season.

George-

[Gardenpro]

This is another species of knotweed. Similar to Japanese but it's only 2' tall with tiny pink not white flowers. Haven't seen the bees on it yet but they aren't working the clover either.
I can't figure out where they are going but wherever it is they sure aren't bringing alot home.