Blue-flowered Tweedia Milkweed Vine for Pollinators
Oxypetalum Coeruleum common names: Blue milkweed vine, Star of the argentine, Southern star, Tweedia caerulea
Oxypetalum Coeruleum Plant Specs
- Perennial: USDA hardiness zones 10-11 (lows -1.1 °C or 30 °F)
- Annual in cool zones with overwintering
- Full sun to part shade
- Height: 2 to 3 feet- in perennial regions can vine up to 10 feet with support
- Spacing: 2-3 feet
- Flowers: pale blue flowers or turquoise blooms with specks of dark purple
- Long, fuzzy, heart-shaped leaves
- long, slender milkweed pods
Oxypetalum Coeruleum Pros
- Long summer bloom period
- drought-tolerant milkweed variety
- Attracts bees and smallinators
- Grows well in Containers
- Blue-flowered milkweed- the only one!
- Leaves turn beautiful deep red in fall
Oxypetalum Coeruleum Cons
- Not enough data from North America growers – monitor for potential issues
- Prone to get late-season milkweed bugs like most milkweed varieties
- Not a preferred host plant or nectar plant for monarchs, but used as a host plant by monarch butterflies in continuous-growing warm zones when other milkweed is unavailable
- Our Minnesota monarch caterpillar hatchlings refused to eat it, but if eggs are deposited on tweedia plants, baby caterpillars will eat, grow, and thrive:
Tweedia Milkweed Plant Propagation Methods
- Start seeds in late summer and overwinter indoors
- Start seeds indoors 2 months before final frost OR
- Seed Starting- Use a traditional seed starting mix with peat moss, perlite, etc.
- Sow seeds after final frost in annual zones
- Sow seeds directly in perennial zones
- Soak seeds in warm water 24 hours before planting
- Use a heated seed mat for faster germination
- Propagate from softwood stem cuttings using rooting hormone
- Start seeds in water
Tweedia Milkweed Growing Tips
- Overwinter in pots for annual zones. Cut back to about 12″ before bringing inside
- If you don’t want additional seedlings next spring, simply cut off the seed pods before they pop open or bind them shut with twist ties, rubber bands, or tie organza bags over the pods if you want to collect milkweed tree seeds. Seeding is not an issue in annual zones.
I’ve seen no monarch activity in our northern garden, but a wayward tussock moth caterpillar scarfed down an entire tweedia caerulea stalk last season. Other pollinators that frequently sip nectar from the flowers: bumble bees, cabbage white butterflies, sweat bees, red admiral butterflies.
If you’ve seen other wildlife activity on your blue milkweed, please share your experience in a comment below…
Buy Tweedia Milkweed Seeds and Plants
While tweedia is easier to say and spell, purchase plants and blue tweedia seeds that are labeled by the botanical or scientific name, Oxypetalum coeruleum to avoid purchasing the wrong plant:
I went out yesterday on a flower mission and found a plant that looks almost like the one pictured here, the leaves look like Swamp Milk Weed, it is about 18″ tall with Blue Flowers.there was a Monarch and a Swallow Tail on another plant near by .
You mentioned Hardiness Zone 10 and 11, I live in Zone 7, could it be the same plant?
The flowers on the plant I found are a little darker blue.
Hi Cliff, if you’re in zone 7 it’s doubtful. Compare to the photos here and find more photos by searching google images, or post a photo on the facebook page: Monarch Butterfly Garden
I had a Monarch caterpillar feasting on bluestar in Anaheim California and there were tropical milkweed, California narrowleaf, pineneedle milkweed and various California desert milkweeds in the yard as well.
I’m in Southern Ca and have had Monarch feeding on this plant.
Comments are closed.