What plant hardiness zone is Union

Union is located at Hardin County, Iowa (IA), USA.

Plant hardiness zone (winter frost zone or gardening zone) for Union is 5a by the USDA scale.

Coldest zone's winter temperature is −20 … -15 °F.

Plants of 5a USDA hardiness zone suitable for outdoor gardening and growing in this winter frost zone 5a USDA.

Union, Iowa @ wikipedia.