By Deb Wiley. Gardeners, start your trowels! Iowa gardeners dig new plants. They enjoy the chance to buy the latest trees, shrubs, perennials, annuals, or vegetables — but prefer selections that have been carefully vetted by garden center professionals. Spring is on the horizon, and Iowa gardeners will soon find an array of new — or fairly new — plants on the benches of the state’s top independent garden centers. Ready, set, dig!