They are annuals, biennials, perennials, or shrubs. The species may be annuals, biennials or perennials. The herbaceous plants can be annuals, biennials, or perennials, without basal or terminal leaf aggregations. Parsnips are biennials, but are normally grown as annuals. They can be annuals, biennials, or perennials, upright or decumbent. Pansies are perennial, but normally grown as biennials or annuals because of their leggy growth. Most are seasonal plants (annuals or biennials), but some are small shrubs. True biennials flower only once, while many perennials will flower every year once mature. Suh has participated in numerous biennials, including the 49th Venice Biennale in 2001. There are far fewer biennials than either perennial plants or annual plants. Seeds that germinate in late autumn become biennials. Though perennial, cultivars may be short-lived and thus best treated as biennials. The perennial species are short-lived and in cultivation treated as biennials. Saar's work has been exhibited in museums, biennials, galleries, and public art venues. Many biennials require a cold treatment, or vernalization, before they will flower.