A member of the borage family, viper's bugloss, or blueweed as it is commonly known, is a biennial flowering plant. It produces blue or violet flowers from late spring through fall and prefers soft soils that the deep roots can quickly penetrate. Viper's bugloss is considered an invasive weed in many regions and is an aggressive self sower. Being a biennial, it will live two years and die. Allowing it to go to seed is critical to maintaining a constant stand of the plant. Protection from frost will keep the plant performing well for its life.
Protect viper's bugloss from frosts, as it can easily be damaged by them. Mulch around the roots of plants growing in temperate climates to shield them from cold. Use a few inches of cocoa bean hulls, shredded bark or leaf mold to insulate the plant, extending the mulch at least six inches beyond the drip line of the plant foliage.
Cut back the plant tops and mulch over the crown of the plant in the fall in climates where it does not overwinter. Do this after the first hard frost when viper's bugloss top foliage has started to die back. This will help to preserve the plant for its second year of growth and protect the seeds from being displaced before they can germinate and take root.
Uncover the plants gently from their mulch blanket in the spring after the last frost has passed. Leave the mulch that surrounds the plant to keep down weeds and retain moisture. Cut away any damaged or dead foliage and stems that didn't make it through the winter, and discard.