Can I “winter” the Star of Bethlehem plants which I bought from a nursery for my summer planters ?
Star-of-Bethlehem is the name given to the star-shaped flowers from the genus Ornithogalum, which are perennial bulbs; as such, one can overwinter them, depending on the hardiness of the individual species in question.
The Ornithogalum species most commonly used in the cut flower and nursery trade (O. arabicum, O. dubium, O. saunersiae, and O. thyrsoides) are all frost tender. If you want to overwinter it, bring it indoors and treat as a houseplant, or lift and store over winter and replant in Spring after all danger of frost is past.
There are also two Ornithogalum species that are hardy in Canada: O. nutens (drooping star-of-Bethlehem), which is hardy to USDA Zone 6 (Canadian Zone 7), and O. umbellatum (garden star-of-Bethlehem), which is hardy to USDA Zone 5. In fact I have a patch of O. umbellatum under my Serviceberry tree that produces dainty green and white flowers every year in late Spring/early Summer; their leaves go dormant entirely by August.