Growing Asparagus Peas For An Edible And Ornamental Garden
Image by Hans Hillewaert
If you love eating asparagus, and growing peas is one of your passions, then the asparagus pea is for you. Here is a guide to growing this little-known tropical plant that combines the beauty of a pea blossom with the flavour of an asparagus spear.
The asparagus pea is a herbaceous annual legume with pea-like flowers that produce frilly pods. They require lots of water throughout the season and do well either direct planted or grown in pots. The edible pods are harvested very small, and steamed or added to stir-fries for a mild asparagus flavour.
Asparagus peas are fairly easy to grow if you provide the right growing conditions. The tricky part is harvesting them at the right time to get the most from the finicky pods. We will discuss everything you need to know to grow and enjoy this beautiful addition to the garden.
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The Asparagus Pea
The Tetragonolobus purpurea is known by many names: asparagus pea, winged lotus, and winged pea to name a few. However, it is neither asparagus, lotus, nor pea.
This 30cm high, low-growing plant produces dark red blossoms akin to a pea and bears edible seed pods with four frilly wings. It is an annual found naturally in many warm, sunny countries with adequate rainfall, such as New Guinea, Indonesia, the Philippines, and around the Mediterranean. Due to their bushy nature, asparagus peas are ideally suited for container growing. Though they do not need trellising, some larger plants might benefit from a few stakes to keep the stem off the ground.
It is a close relative of the Goa bean, sometimes called asparagus bean, which is a long trailing vine grown mainly for its dried seeds.
Planting And Germination
Soil bed preparation for asparagus peas is the same as other leguminous plants. A lightly worked soil with adequate compost is all that is required for this easy-to-grow vegetable.
The asparagus pea needs a spot in full sun to thrive, and a high germination temperature of 15C to 20C. It can be started in pots indoors in March or April, or direct sown into the garden after the danger of frost has passed. For sowing, plant the seeds roughly three times as deep as the diameter of the seed, and space the seeds 20cm to 25cm apart to give the plants room to grow. The seeds will typically germinate in 7 days under glass. The seeds can be soaked overnight to aid germination.
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The Growing Season
Asparagus peas have a fairly long growing season of 80 to 100 days, and they require 12 hours of sun per day on average to flower. It can be advantageous to have them in pots so they can be brought indoors as the fall frosts are imminent, and they can be positioned to receive maximum sun exposure.
To replicate their natural environment, you should keep your asparagus peas well watered. Applying a layer of mulch is very beneficial for keeping the plants moist, and also chokes out competing weeds. Asparagus peas are threatened by similar pests as peas and beans and should be treated accordingly.
Also like their more common relatives, asparagus peas are legumes and will take nitrogen from the atmosphere and fix it into the soil in a process called nitrogen fixation. Because of this natural phenomenon, asparagus peas will grow quite nicely without added fertilizer.
Harvesting, Eating, and Storing
As your asparagus plant grows, and blossoms begin the develop seed pods, the tricky part begins. The seed pods need to be picked quickly and very small. The best time to harvest the pods is when they are at most 3cm long, and the flower is just beginning to dry on the pod. Any bigger than this and the large pods become stringy and lose flavour. They should be eaten quite quickly after harvesting, as they will begin to wilt in the fridge if left more than a day.
The pods have a mild flavour reminiscent of their namesake: the asparagus. They can be added to a stir fry, or lightly steamed for 5 minutes and then eaten with butter or margarine and garnished with your favorite herbs. They also work well cooked into sauces, but they will quickly lose their flavour the longer they are cooked.
The pods can be eaten fresh, but it is not generally a pleasant experience. The pods are astringent and will leave your mouth very dry. However, the flowers can be added fresh to a salad for a beautiful garnish and extra flavour.
Since the pods are eaten so small, the yield from each plant can be quite low. If you only have a few plants, it can take a few days to gather enough for a meal. Thankfully, asparagus peas freeze very well. You can freeze them until you have enough for your next family gathering, or you can store them to enjoy throughout the winter.
If you miss a few pods that have become very developed, don’t worry. You can let them mature and dry completely to save the seeds for next year or cook them to replace dried peas and beans in your favorite recipes.
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Growing Asparagus Peas In Northern Climates
Due to its long growing season and semi-tropical nature, asparagus peas can pose a few challenges for gardeners in northern climates. But of course, if you are a northern gardener, then you are well used to the bitter tests that nature puts your garden through.
If you plan on growing your asparagus peas in the garden, you will probably have to start them indoors to achieve an adequate soil temperature for germination. Transplant them into the garden after all chance of spring frost has passed. Since the asparagus pea is so frost-intolerant, you need to make sure they are transplanted early enough so you have harvested all you can eat before the killing freeze comes again in the fall.
Container growing might be the simplest option for your cold-climate garden. Once your seedlings are established in their pots, you can put them outside for the summer to soak up the heat from the sun. As the danger of the first frost approaches, you can bring the pots in overnight, or keep them in on particularly cold days.
Don’t let the weather get you down, and keep you from enjoying this beautiful and edible legume. Experimenting in the garden is one of its joys, and what better way than try out an easy-to-grow, unique plant that will add a little extra protein to your diet.