Butterfly Pea Flower (Clitoria ternatea) is an easy growing herbaceous twining vine with striking blue flowers that can be used as natural food dye.
Butterfly Pea Flower / Clitoria Ternatea
Butterfly Pea Flower (Clitoria ternatea) is part of the Fabaceae family. Also known as Asian pigeonwings, bluebellvine, blue pea, cordofan pea and Darwin pea, the tropical legume climbs over a trellis or a fence and produces vivid blue, purple, mauve and white flowers.
Aside from its anatomical shape, the flower has risen to fame as a botanical used in gin. Ink Gin from Husk Distillers in NSW were arguably the first to harness the properties of this flower which lends a blue colour to liquids and turns pink when the pH is changed such as by adding citrus or tonic water. The flower contains colour-changing anthocyanins and for the science behind it, this article explains it in detail.
The plant grows as a vine or a creeper and reaches between 1-2 metres in height. It’s considered a perennial plant in warm and temperate climates, though I don’t have first-hand experience whether it will survive Sydney winter in my part which doesn’t get frosts. As temperatures start to cool down, the plant begins to shed some leaves and the flowers get smaller in size. I will update this article in early spring with the progress.
How to Grow Butterfly Pea Flower
Clitoria ternatea is easy to grow from seed. In spring, prepare the seeds by lightly scratching the surface with a nail file and soak them overnight in water. The next day, sow them either direct or raise as seedlings by planting 2cm deep. My preference is to raise seedlings to protect them from being eaten by birds or destroyed by other critters. If planting in the ground, for protection, cover the spot with the top half of a clear plastic bottle with the lid removed.
The seeds generally take two to three weeks to germinate. Once the seedlings have grown to at least 4-5cm in height, transplant them in the ground, against a wall or a trellis in a position that gets full sun or part shade. It takes 90 days until the plant begins to flower. It may seem slow at first, but once the flowers start forming, it is prolific and continues flowering from early summer until late autumn.
Butterfly Pea Flower Plant Care
Very little maintenance is required. Keep it moist while it’s growing, but don’t overwater. Once it’s established, it becomes drought tolerant. As a legume, its nitrogen fixing capabilities means it needs little fertiliser. If you’ve prepared the soil beforehand, as is my preference, it doesn’t need additional fertiliser. Furthermore, the vine seems to be fairly resistant to garden pests.
Harvesting & Seed Saving
The flowers bloom at their best for a day or so and they can be harvested and dried to use. However, I prefer to pick mine a couple of days later when the flowers have shrivelled and started to dry on the vine. They can then be easily harvested by gently pulling on the end of the flower leaving the forming pod behind. This has the advantage to allowing the pods to form, dry on the vine then collected for seed saving.
As the pods mature, the begin to fill out with seeds and change in colour as in the photo above. If you’re planning on saving seeds, keep an eye out on the pods as they can dry and shrivel very quickly at times and spill their seed.
Tips for Growing Butterfly Pea Flower
- When harvesting the flowers, leave them to dry on the vine then gently pull them out leaving the developing pod intact.
- Store the dried flowers in a glass jar with a desiccant inside. Keep the jar out of the light at room temperature.
Culinary Uses of Butterfly Pea Flower
The flowers of Clitoria ternatea are commonly used as natural food colouring. They don’t have any flavour and can be added to sticky rice, desserts or anything else you like to colour, keeping in mind the pH colour change characteristic.
Butterfly Pea Flower in Cocktails
The dried flowers can be steeped in hot water to make a tea, then mixed with honey. Add lemon and watch it change colour from deep blue to purple. The tea can also be made into a simple syrup to use in cocktails.
The flowers can also be steeped into spirits such as gin and vodka. The length of infusion is dependent on the colour required however, make sure you fine strain the flowers after use and keep the infused spirit in the fridge.
Butterfly Pea Flower is a beautiful vine to grow in your edible garden. In fact, growing this flower could not be any easier. The flowers add a fun element to food and drinks and as an ornamental, the plant will reward you with beautifully coloured blooms all through summer and autumn.
Want to Know More?
You’ll find more information on how to grow butterfly pea flower, how to pair it with food and spirits, and how to use it in cocktails including a full recipe in my 260+ page digital book GROW YOUR OWN COCKTAIL GARDEN available now.