Getty Images 5. Many sunflowers are North American natives, and some of those are perennials. But the Helianthus annuus species, known as common or annual sunflower, is a native annual.

Annuals can be planted any time after the last frost in spring—even in the heat of summer to refresh garden beds or pots that have fizzled out. Perennials should be planted in spring or fall.

Because of this, Aul Cervoni notes that annuals bloom for much longer than perennials, sometimes even all season long. They're ideal plants for containers or temporary gardens.

Here are 7 worth adding to the garden Gardeners are embracing native plants more and more for their environmental benefits, But native annuals are often overlooked ...