Oxypetalum Coeruleum

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.

Pollinator Plus

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:

1. Buy Tweedia Milkweed Seeds Here
   
2. Find Tweedia Seeds on Etsy

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