Posted: 04/06/2014 at 12:05
I wouldn't even consider any of the just pay postage offers, unless you have a greenhouse and have the time/inclination to mother the plants for at least 12 months before putting them in the garden.
They do work out ok sometimes, last year i got the "free" 24 lavender plugs, i planted them in modules and have kept them in the greenhouse, they are now around about the size where i could consider putting them in the garden but it's literally taken 12 months.
Probably the best ones i've had from the pay postage offers was 4 dwarf buddleja's these were actually large plugs, and being tough as old boots they only needed potting on and hardening off before going in the garden and have done fine.
Everything else, ie the perennials expect to have to pot into modules, then repot and keep in a greenhouse over winter, before even thinking of putting them out next spring. You are unlikely to get anything if you plant them out the same year you get them in the post.