The popular flowering perennial (also known as Delphinium), which has been cultivated in cottage gardens for many centuries, is absolutely hardy even in harsh climates and does not need any special winter protection.
Larkspur does not need winter protection; it only needs to be cut back in the fall
Cut back delphiniums in autumn
To prepare for winter, cut back the faded delphiniums in autumn to just above the ground and then thoroughly mulch the root area with mature, humus-like compost. This measure should actually be sufficient as a preparatory measure for the winter, because - if it is a perennial variety - the delphinium will sprout again in spring. Only with annual or biennial Delphinium varieties should you leave the inflorescences so that the plant can form seeds and sow itself again.
Overwinter delphiniums in pots
Many people prefer to keep delphiniums in pots, because the delicate green is coveted snail food - and many a snail invasion has ensured that no stately perennials could grow from the first tender shoots. Larkspur in a pot does not need any special protection either, you only need to wrap the pot in very frosty temperatures with a warming mat or similar. Otherwise, a sheltered place outdoors is sufficient, at best on a house wall.
tips and tricks
The lower varieties Delphinium belladonna, which remain significantly smaller than, for example, the Elatum perennials, are particularly suitable for containers.