planted some roses last November - now beginning to grow - should I prune them and how severe should the pruning be?
Surely there were pruned when you planted them in November and have not had much chance to grow since.
The roses I planted are just starting to show buds behind where they were previously pruned, so there is no old wood to prune. Thus I am leaving well alone. But its not easy to say without seeing them. For the record most plants respond to day length rather than temperature, in terms if inducing flowering (which is why you prune) But Roses are unusual in that they don't respond to changes in day length
Yes they were pruned when I planted them - the stems are now about 15" long with the beginnings of buds. Should I prune them down to just above soil level?
It all depends on what sort of roses you planted, that is species, climbing, Hybrid Tea, Florabunda or rambling. Assuming they are Hybrid Tea or Florabunda, they will be grafted onto the root stock of a different type of rose. It is very important that you do not prune any lower than the graft or you will be left with growth from the root stock (probably a rambler). The graft will look like a lump low down on the main stem. Having established where the graft is, at least in the first years, you are pruning to establish the shape at least as much as for flower. There could still be some damaging late frosts, so leave at least two buds on each stem in case one is killed by a frost. Generally, roses are pruned to half way at the start of winter in order to prevent them rocking in high winds and creating a hole which then fills with water and freezes, killing the plant. They are then pruned again at this time of year, and it is this one that will determine the number and size of flowers in the summer. Hybrid Teas and Florabundas tend to be repeat flowering so long as the spent flowers and the hips are removed in summer. Species roses, climbing roses and rambling roses do not tend to be repeat flowering and are pruned for shape and to clear crossing branches only.
Wait a while till any possibility of frost is past, It won't hurt to prune them in April/May if they look a bit leggy. You can cut them down to about 6 inches, take out any thin, weedy looking stems, and try to find any outward looking buds before you cut as these grow outwards giving the bush shape as they grow. Roses are quite hardy to pruning so you are unlikely to kill them unless you cut them too close to the soil, too early.
