How hardy is my plant?
For perennials, the label indicates to which hardiness zone it belongs. The hardiness zones were developed by the United States Department of Agriculture. This way you can see at a glance how hardy the plant is.
If the label states zone 7, it means that this plant species in the Netherlands can tolerate frost up to -17 ° C. It is important to consider other elements as well. Is the plant wet, with a north or east wind? Is there snow on the plants? You can protect the plants from frost by covering the plants with straw, leaves or branches. In case of a severe frost period, perhaps an extra fleece cloth.
For plants in flower pots, you should lower the zone by two, because plants in pots freeze earlier than in the garden. Of course it is better to let the pots overwinter frost-free.