Posted: 13/11/2013 at 18:18
For me alstromerias are very hardy and in flower for months. It is mild here so maybe not the best to advise but.........
. Although they die down in winter they are susceptible to spring frosts. Then they will be set back. I would certainly overwinter in coldframe. Leave it amd forget it until the spring. Harden it off gradually then but get it back under cover if frost is forecast.
Siting alstromerias is important. They have a dormant period in late summer where they die down after flowering. This leaves a big...according to size of alstromeria....gap in the border. I have moved mine behind a miscamthus and dahlia, for example, so that the gap in the border is disguised. ( My alstromerias flowered from late April to mid August )