Eat home-grown produce all year round without lifting a finger

But while we tend to think of perennials as an element of our flower borders, Martin Crawford sees them as a surefire way to provide home-grown food throughout the year. In his new book, How to Grow Perennial Vegetables (Green Books, £14.95) he shares the secrets of this often overlooked group of plants.

Most gardeners could name a few perennial vegetables – asparagus, globe artichoke and rhubarb are probably the best known, but we’d be hard-pressed to come up with the list of more than 200 plants that feature in this book.

“We don’t have much of a history or culture of growing perennial vegetables in our gardens over the last 100 years,” says Crawford. “In addition, in Britain we have relatively few perennial native plants suitable for vegetable cultivation. Annual vegetable species have gradually been introduced to gardeners over many years from other parts of the world, but the edible perennials grown elsewhere – of which there are many – were rarely brought with them.”

Crawford says that for gardeners, as with the larger picture of agriculture, sowing annuals, harvesting the crops then digging over the soil has become the norm in terms of vegetable- growing. This might be the routine many of us are used to, but he says there are strong arguments in favour of switching to perennial vegetables. High on the list is resilience. “Once planted and established, most perennial vegetables can shrug off problems including drought,” he says. “For example, right now I have half a dozen perennial crop shoots coming through the ground even though we’ve had no rain for a month and I haven’t watered.” Growing veg this way needs less work – you only have to plant once, so there’s less digging, and gradually less weeding, as time goes by.

From trees to bulbs and climbers to aquatic plants, the list of edibles Crawford describes is extensive. Some are plants you’ll know, but might never have considered eating.

Take beech trees. The young leaves are said to make good eating for their first three weeks (they have a lemony zing and are good in salads), after which they become a bit tough. Crawford explains that the kernels of the seeds (beech nuts) are tasty, but small and fiddly to get at. For all of the plants listed in the book he gives advice on cultivation and maintenance as well as harvesting and culinary uses.

Crawford says people might be surprised at how many perennial vegetables there are to choose from. “Some of the surprises may be finding out that they already have some edible perennials in their gardens without knowing – for example columbine, day lilies and mallows,” he says.

“The list includes trees, shrubs and lower perennial plants so hopefully there will be vegetables that appeal to everyone and that are suitable for all sizes of garden.” Columbine, also known as aquilegia is a cottage garden favourite that merrily self-seeds. As well as admiring its nodding flowers you can add the young leaves and the flowers to salads. Another surprising salad ingredient is the fleshy leaf of the ice plant, Sedum spectabile. Many gardeners grow it for its plentiful pink flowers which attract butterflies, but Crawford says that the leaves, whole or roughly chopped, are succulent and juicy and are a great addition to salad on a hot summer day.

It might comes as news that the leaves and young shoots of red valerian have a lovely broad bean flavour and can be put in mixed salads or lightly cooked as a vegetable, but other plants like cardoon, chicory, Jerusalem artichoke, chives and garlic are more familiar as vegetables. Crawford says that some plants we tend to grow as annuals in the veg patch – Swiss chard, for instance, can be kept going if you pinch out the flowering stems. Wild rocket is another salad favourite which happily over-winters. Asked for his recommendations for beginners, Crawford suggests “perennial chicory for salad leaves; Chinese artichoke for crunchy white tubers; Good King Henry as a perennial spinach; and Siberian purslane for almost all-year-round beet-flavoured leaves.”

There’s certainly plenty of food for thought, even if it takes a leap of faith to harvest plants that you might never have looked at as a food source. Bamboo shoots are one such example and Crawford’s favourite are the Phyllostachys species. The top 30cm of new growth can be harvested and once you’ve removed the outer husk and steamed it for five to ten minutes, it’s the perfect addition to a stir-fry. Other plants might be completely new to Scottish gardeners. Mashua (Tropaeolum tuberosum) is a perennial climber and a tuber crop that originates in the Andes. The leaves are edible; if autumn is long and mild it will produce seeds which can be used like capers; and when the foliage dies down after the first frosts, the protein-rich tubers can be dug up as required and cooked like any other root vegetable. You can either leave a few in the ground to regrow in spring or store them in paper sacks over winter.

With so much choice it can be difficult to know where to start in this new world of perennial vegetables, but Crawford encourages us to be brave and stop strictly dividing plants into the decorative and the edible. “The divide is gradually being eroded, both by books like this and the increasing popularity in food foraging and growing-your-own,” he says. “It’s an attitude of mind too, we need to start thinking, ‘Hmm, I wonder if that is edible,’ rather than, ‘ooh-er I wonder if that is poisonous’. If you find you have perennial vegetables in your garden that you didn’t know about, the first step is to try them before you move on to some of the many other possibilities.”

So whether it’s mashua, water chestnuts or plain old aquilegia, perennial vegetables are waiting to be discovered.

How to Grow Perennial Vegetables by Martin Crawford (Green Books, £14.95) is out now.