Last year I got two orders of SDBs in July from well known sources One batch went directly in the ground and the second was potted. The potted ones I kept in a garden cart and they were in the sun part of the day but I would pull the cart into the shade during the hottest sunniest parts of the day. The ones in the ground stayed green, rooted in, but didn't increase very much. The ones in pots really grew and put up lots of increase. When I planted them in October the pots were full of roots. This spring the ones that I planted directly in the ground all bloomed but are small plants with 2-5 increases. The formally potted ones were small clumps and some had 2-3 bloom stalks. Potting for a few months before transfer to the ground is more work but worth it IMHO.
