Low temperatures leave plants in the cold David Trinklein and Michele Warmund University of Missouri Extension COLUMBIA, Mo. - Winter-hardy perennial flowers likely will survive April’s historic low temperatures across Missouri, said University of Missouri Extension horticulturist David Trinklein. Their tender annual counterparts, however, may not be so lucky. MU Extension horticulturists across the state answered numerous calls from concerned gardeners about freeze damage to their flowers and flowering shrubs as temperatures dropped into the 20s. Perennials, even those in tight bud stage, likely will face minimal damage, Trinklein said. His callers included someone who feared losing a peony planting that has been in the family for more than 140 years.