Since most carnation species are biennials, they could survive at least one winter, especially since many are considered to be extremely frost hardy. In practice, however, carnations are often only cultivated as an annual, since they do not die due to frost but due to moisture.
Sub-zero temperatures don't usually bother cloves
Overwinter cloves properly
Many types of carnations, including the very robust Carthusian pink, are considered to be extremely hardy. These plants prove to be frost-resistant even at temperatures of around - 25 °C and are therefore also suitable for regions that are very cold in winter. However, other Dianthus species are more sensitive and should therefore be provided with light winter protection. For example, it makes sense to cover it with brushwood (especially spruce branches), as this still allows the plants to get enough air and light.
Carnations often die when wet
However, the biggest problem with cloves is not so much their sensitivity to frost, but their sensitivity to moisture. Garden carnations and country carnations in particular do not die in winter because of the cold, but because they are simply too wet and they rot. After all, these are plants that love drought. So if you want to get your carnations through the winter successfully, you should try to avoid excessive moisture as much as possible.
Overwinter cloves in pots
Like their relatives in the garden, carnations in pots are basically hardy and can overwinter outdoors. Since the root system freezes faster in the narrow pots, the planters should be protected against penetrating frost. This is done by placing the bucket on a styrofoam plate (€45.00) and wrapping it with an insulating material, such as a raffia mat. Furthermore, pot carnations also have - or especially - the problem of moisture: On the one hand, the plants have to be watered on frost-free days in order not to dry out - on the other hand, moisture also leads to root rot and thus to the death of the plant.
tips
Actually, you don't need to worry about overwintering or not: just leave the last flowers on the plant and finally either collect the ripe seeds (and sow them in spring) or wait for the self-sowing. In this regard, carnations are very reliable.