By Mandy Darrington
Iowa State University
If you are a gardener, who loves seeing a touch of blue in your flower bed, tweedia (Tweedia caerulea) is the perfect plant for you. The genus, Tweedia, was derived from the surname of James Tweedie. During the mid 19th century, he was the head gardener at the Royal Botanic Garden in Edinburgh. After immigrating to South America, Tweedie traveled throughout the continent sending plants that he found during his travels back to Scotland.
Tweedia is known for its distinctive turquoise blue star-shaped flowers and green/gray felted leaves. Prior to being identified as Tweedia caerulea, tweedia belonged to the genus Oxypetalum meaning sharp petal. Its five-petaled flowers bloom in loose clusters, which give way to boat-shaped seedpods. The seedpods are characteristic for the plant family in which it belongs, Asclepiadaceae.
In its native habitat of Uruguay and Brazil, tweedia is a tropical vine or subshrub. An individual plant can reach a mature height of 2 to3 feet tall and may require staking to retain its shape. However, in USDA Hardiness Zones 4 and 5 it is an annual and will grow 12 to 24 inches tall. Grown as an annual, tweedia will tolerate a wide range of growing conditions, but prefers full sun and moist soils. It is also wise to plant this annual in a sheltered location away from heavy wind and rain to protect its delicate flowers.
View a collection of tweedia, in Joey & Jesse’s Herb Garden at Iowa State University’s Reiman Gardens. In this garden, it accents a collection of Elephant Ear with its sky blue color and tiny star-like flowers.