When describing plant species and varieties, including perennials, the frost resistance zone is given (from 1 to 12). The smaller the zone number, the greater the frost resistance of the plants.The following zones are distinguished in Poland: 5B (from -26ºC to -23ºC), 6A (from -23ºC to -21ºC), 6B (from -20ºC to -18ºC), 7A (from -28ºC to -15ºC), 7B (-15ºC to-12ºC).
This means that, for example, perennials that survive in zones 1, 2 and 3, i.e. with a minimum winter temperature below -34ºC (not seen in the most severe winters), are the most resistant to frost and even the site is not afraid of them. exposed to strong, frosty winds where snow will not last long.
Perennials that tolerate the conditions of zone 1 in our gardens include, for example, arctic pyrethrum, zones 2 - e.g. yarrow, concentrated bellflower, meadowsweet, blue polygon, saxifrage, New English aster and Neo-Belgian, Labrador violet.A zones 3 - incl. acornfish, pearl anaphalis, large-leaved brunera, rock marshmallow, concentrated and peach-leaved bellflower, whitish cornflower, ash-leaf diphtheria, wall cymbalaria, Siberian thistle, spiky rotator, sercolist tiarella.
However, it must be remembered that even the most resistant to low temperature plants may not survive the winter if we do not care for them properly.
