April 2021
Tweedia Caerulea
Tweedia caerulea, also called blue milkweed, star of the Argentine, or southern star, is most commonly called just Tweedia. Oxypetalum caeruleum is the old botanical name. Named after James Tweedie of the Royal Botanic Gardens of Edinburgh, was the first to collect this plant mid-19th century. Truly blue flowers are rare enough, but one that blooms all summer, even rarer. It is a member of the milkweed family, and the only milkweed with blue flowers. Research into this lovely plant suggests that Monarchs will use it in the event they can’t find their preferred, more common milkweed varieties.
Yes, at first glance, it looks as if it desperately needs water, but this is the way it’s supposed to look. It invites touching. The beautiful clear blue flowers will fade to purple, and are followed by a six inch long, boat-shaped seed pod. New vines are apparently easily started from these seeds. As with other milkweeds (there’s a reason they’re called this…), it will ooze a milky white sap when cut or damaged. Be a little careful - it’s a mild irritant, and to those with a sensitivity, highly irritant. (Don’t ask me how I know.)
The plant has been called a twining vine, meaning that it will wrap around a support if one is provided. However, the experience of several bloggers might suggest that it needs help to grow on a support. So be prepared to tie if yours doesn’t show the inclination either. If no support is provided, it will form a mound two to three feet wide, and will continue to bloom all summer. This plant is native to Brazil and Uruguay, and is a tropical, only growing unprotected in zones 10-11. In our zone 9a climate, it will need to be protected from frost, or taken indoors in winter. The thick fuzzy leaves might suggest that it’s a desert-y kind of plant, but it in fact, prefers fairly rich, but well-drained soil. In its native habitat, it grows in full sun. I plan to keep mine in a pot so that it can be moved if full sun proves too much, and more easily protected in the winter.
Yes, at first glance, it looks as if it desperately needs water, but this is the way it’s supposed to look. It invites touching. The beautiful clear blue flowers will fade to purple, and are followed by a six inch long, boat-shaped seed pod. New vines are apparently easily started from these seeds. As with other milkweeds (there’s a reason they’re called this…), it will ooze a milky white sap when cut or damaged. Be a little careful - it’s a mild irritant, and to those with a sensitivity, highly irritant. (Don’t ask me how I know.)
The plant has been called a twining vine, meaning that it will wrap around a support if one is provided. However, the experience of several bloggers might suggest that it needs help to grow on a support. So be prepared to tie if yours doesn’t show the inclination either. If no support is provided, it will form a mound two to three feet wide, and will continue to bloom all summer. This plant is native to Brazil and Uruguay, and is a tropical, only growing unprotected in zones 10-11. In our zone 9a climate, it will need to be protected from frost, or taken indoors in winter. The thick fuzzy leaves might suggest that it’s a desert-y kind of plant, but it in fact, prefers fairly rich, but well-drained soil. In its native habitat, it grows in full sun. I plan to keep mine in a pot so that it can be moved if full sun proves too much, and more easily protected in the winter.