how do I prune evening primrose for winter?

Question

We leave in Colorado at 6000 feet elevation

Answer 1

Oenothera biennis, aka common evening primrose is a biennial which means it lives for 2 years then dies. The first year it forms a basal rosette of leaves and no flowers. The second year, it sends up the flower spike(s) and sets seed. To keep it in the garden, it is necessary to collect seed or allow the plant to self-sow. Cut the flower stalk down or remove the plant. It will not come back next year.