Biennial weeds need 2 years to complete the life cycle. Often the biennial weed spends the first year of its two year cycle as a small cluster of leaves. After exposure to cold winter temperatures, the reproductive mechanism is triggered, flowers and seeds are produced. Perennial weeds persist for more than 2 years. It may be woody tissue that remains above ground or it can be a rootstock that survives in the soil and regrows new vegetation each year.
Some perennial weeds require many years of growth before seed production occurs.
Most perennial weeds can be spread by vegetative plant parts as well as seed. Recommendations on this web site do not endorse any commercial products or trade names.