propogating albizia from seed

Well, I've checked one encyclopaedia and it says propagate by seed in autumn (but doesn't tell you how) and the other encyclopaedia says to propagate from seed in spring - sow in small pots under glass in March/April, so I'd go with the second one, personally.
You could try some now, specially if you have a heated greenhouse, or somewhere warm and bright indoors. If you don't have a heated greenhouse though, and they germinate, you've then got to keep them indoors all winter and they will probably get very leggy. Even if you wait till spring, without a greenhouse ,you'd have to germinate them similarly and then grow them on indoors till the weather's warmed up.