It's so hard to throw out gardening magazines. Each has info that
"might come in handy some day." So I'll post here and Google the
archive when the question next comes up.

'Organic Gardening', June/July 04 has the following:

"Plants have a longer-than-average juvenile period and sometimes fail
to bloom as expected....Juvenile plants should be fertilized only once
a year...fertilizer with a balanced NPK ratio. Established wisteria
needs little fertilizer...water only during drought and fertilize if
the foliage yellows and new growth is poor. ...produces blooms on old
wood...don't prune heavily in winter and early spring...prune after
blooming (get a book for specifics). W...needs at least 6-8 hours of
full sun to bloom best."