Oxypetalum: The Blue Star Flower for Bouquets

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Oxypetalum is the soft blue “star” that makes a bridal bouquet or a spring arrangement look like a watercolour. True blue is rare among flowers, so florists value oxypetalum as a natural accent with no dye involved. Here is what the plant is, how to recognise it, what it pairs best with and how to keep it fresh in a vase for longer.

What is oxypetalum

Blue oxypetalum (Oxypetalum coeruleum, known in older references as tweedia, Tweedia caerulea) is a subshrub of the dogbane family native to South America. In the wild it is a twining vine with downy grey-green leaves; for cut flowers it is grown in greenhouses, so florists can get it all year round.

The flowers are five-petalled stars 2–3 cm across, gathered in small clusters. Buds are pinkish, open flowers are pure sky blue and turn lilac as they age. Besides the classic blue, there are white and pink varieties.

Why the stem “bleeds” white sap

Like many plants in the dogbane family, oxypetalum releases milky white sap when cut. It sets quickly and blocks the stem, so the flower drinks less water. To prevent this:

1. Cut the stem at an angle with a sharp knife.
2. Hold the cut end under warm running water for 20–30 seconds until the sap stops.
3. Put it straight into a vase of clean, cool water.

The sap can irritate the skin, so people with sensitive skin should wear gloves and avoid touching their eyes.

View full-size photoOxypetalum features five-petalled blue flowers in clusters.

What to pair oxypetalum with

• White and cream roses — a wedding classic in which oxypetalum becomes the “something blue”. Peony-shaped roses work well too.
• Pink and peach tones — lisianthus, spray roses and ranunculus create a soft, fresh pastel palette.
• Light fillers — gypsophila and silvery eucalyptus highlight the cool shade of the flower.

Oxypetalum works best as an accent: a few stems stand out more than a large amount, because the small flowers get lost in a mass.

Vase life and care

With the cut treated properly, oxypetalum usually stays fresh for about a week, and new buds keep opening. To make it last:

• Change the water every 1–2 days and recut the stem, rinsing off the sap each time.
• Remove any leaves below the waterline.
• Keep the vase away from radiators, direct sun and fruit.

Oxypetalum in wedding floristry

Thanks to its rare blue colour, oxypetalum is a favourite for bridal bouquets, buttonholes and table decor. It is light, has no strong scent and photographs beautifully. If you are planning a wedding bouquet, check availability in advance: oxypetalum is imported and florists keep limited stock. See ready-made options in bridal bouquets.

Other flowers and greenery for bouquets are listed in our florist’s glossary.

FAQ

What is another name for oxypetalum?

Tweedia (Tweedia caerulea) is an older name for the same species. It is also called blue star.

View full-size photoOxypetalum adds a blue accent to bridal bouquets.

Does oxypetalum come in other colours?

Yes, there are white and pink varieties, but classic blue is the most popular.

Why does oxypetalum wilt quickly?

Usually because milky sap blocks the cut. Rinse the cut under warm water and recut it each time you change the water.

Author: Maria Svitlovir

Graduated from Taras Shevchenko National University of Kyiv, Institute of Biology and Medicine (2001). BSc in Biology, MSc in Horticulture. Writes about plants, works at a garden centre selecting and repotting plants, and contributes to plant reference guides.

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