The beauty of lupins

Flowers, stock feed, soil improver, superfood... lupins can do so much more than add colour.

Purple and orange Russell lupins

Lupins can be many things – colourful flowers, valuable stock feed, soil improver, weed – or the new superfood. The botanical name Lupinus derives from the Latin for wolf, possibly from a belief that the plants ravenously used up the soil’s nutrients. However, lupins grow in poor, sandy soils and are able to “fix” their own nitrogen, an attribute of legumes in the Fabaceae family. Close relatives are peanuts and soybeans.

Lupin seeds have been used as a food since ancient times. Also called lupini beans, they’re pickled to make a popular snack around the Mediterranean. However, the majority of lupins are grown for stock feed and green manure crops. Australia is the world’s leading grower of lupins, mainly in Western Australia where they’re used as a rotation crop with wheat to add nitrogen to the soil and break cereal disease cycles. Their deep taproots help them succeed in dry, infertile soil.

Russell lupins in Fiordland National Park on New Zealand’s South Island.

The dominant species grown is narrow-leafed or Australian sweet lupin (Lupinus angustifolius), which has white flowers. In the NSW Riverina, varieties of white lupin (L. albus) are being developed that eliminate the natural bitterness and toxicities as well as increase yield and disease resistance. Lupins’ potential as a “superfood” comes from the seeds: they’re 35-40 per cent protein, high in dietary fibre and B vitamins such as folate, low in fat, gluten free and low GI. On the downside, they can trigger an allergic reaction in a small percentage of people. Australian growers such as Lupins For Life supply products such as lupin flour, kibble, crumb and flakes to bakeries, manufacturers and consumers.

Russell lupins make excellent cut flowers

PhD candidate Arineh Tahmasian at Perth’s Edith Cowan University has identified more than 2500 proteins from lupin seeds in the quest to turn feed into superfood. “We’re looking to identify lupin varieties with lower allergenic and higher health-enhancing proteins suitable for food applications or to use in future breeding programs,” she says.

Gardeners will be more familiar with Russell lupins (L. x regalis), hybrids bred by Englishman George Russell. The spectacular summer flower spikes are packed with pea flowers in a rainbow of jewel, pastel and bi-colours; they make excellent cut flowers. These herbaceous perennials with soft, fan-like leaves die down over winter but reshoot each spring, and are best suited to cool and temperate climates. The common garden lupin L. polyphyllus looks similar but is starting to become weedy in many cool zones worldwide.

Q&A

Why would our ‘Sunshine’ passionfruit have fruited late so that the many green fruit are unable to ripen in our cold winter?

Gayle Corbould, Margaret River

‘Sunshine Special’ is a vigorous, cold-tolerant variety developed in Perth. The plants are not grafted, which avoids the problems of rootstocks suckering. It can give two crops – the main summer crop plus a small winter one that is not as sweet. It’s also possible for the fruit to stay green on the vine through winter and ripen when the weather warms. The timing of flowering can be affected by weather patterns and the amount of sun received.

My mother and I planted a daphne 40 years ago but its leaves are drooping and it looks sick. I’ve lost some azaleas in recent years and a rhododendron has some dieback. Any thoughts?

Jill Smith, Perth Hills

Daphnes are touchy plants that die suddenly; they’re prone to root rot. They’re more susceptible when affected by viruses, poor drainage or excessive heat and rain. Once the leaves look pale and droopy, death is usually rapid. Phytophthora root rot affects many plants (including azaleas) and causes dieback in the bush. It spreads through soil and water and has no cure. The best defence is keeping the soil healthy.

What vine would grow on our north-facing fence? It’s black, next to the driveway and gets very hot.

Shauna Hockley, Adelaide

The ideal would be bougainvillea that loves these conditions; choose a medium-size variety. Also look at native snake vine (Hibbertia scandens), bower vine (Pandorea jasminoides) or ivy-leafed pelargoniums.

July prize

Send your questions to: [e-mail] or Helen Young, PO Box 3098, Willoughby North, NSW 2068. Website: helenyoung.com.au. The best question for July wins Glow’s Ironbark Fire Pit of weathering steel, worth $139 from glowheating.com.au.