I've grown blyxa japonica before, when you plant it first of all it goes through a transission stage where it dies back totally and then regrows, this seems to happen for everyone with this plant, so the condition it arrives in won't really matter tbh. The root stalks are fairly robust anyway so you should have no problems.
It does need a fair bit of light though and CO2, at least 2WPG or it just dies back totally never to reappear again
I will check out Wackers tomorrow, thanks for the tip off.
Got some nice Cryptocoryne balansae in aquatic village last week so it ain't all bad!