What plant hardiness zone is Rock Island
Rock Island is located at Rock Island County, Illinois (IL), USA.
Plant hardiness zone (winter frost zone or gardening zone) for Rock Island is 5b by the USDA scale.
Coldest zone's winter temperature is −15 … -10 °F.
Plants of 5b USDA hardiness zone suitable for outdoor gardening and growing in this winter frost zone 5b USDA.
Rock Island, Illinois @ wikipedia.