While gardeners struggle with hosepipe bans and allotmenteers try to keep their annual crops going, perennial veg may prove a better bet in the long run.
So says Harrison Fannon, vegetable gardener at Blenheim Palace and co-founder of Worthy Earth, a veg-growing company which designs, maintains and consults on market gardens nationwide.
“You can buy perennial versions of different types of vegetables, where the plant comes back year after year, it isn’t an annual.
“Once they’re established and their root systems have gone down so far, they won’t need as much watering and they are much more climate resilient,” he says.
You can also buy perennial celery, perennial kales and other vegetables which are much more adapted to withstanding hot summer weather, have longer lifespans and are less likely to run to seed, he adds.
“We are growing a lot of perennial salads like rocket, salad burnet and something called buck’s horn plantain, things you might actually find in the wild but are fantastic to add to your veg garden and don’t require half of the maintenance of annual vegetables. They are much hardier and have a much more interesting flavour profile.”
“They are becoming more common but are still a little bit off-piste,” he continues.
The most common include rhubarb, asparagus and globe artichokes. Other leafy perennial veg make good plant partners in the allotment for various reasons.
“Because they stay in the ground they are able to produce shade for your other vegetables and they also have much deeper root systems, so they are able to draw water out from deeper in the soil.”
So, what might gardeners try to grow?
Perennial rocket
“We’re growing wall rocket, or Turkish wall rocket, as an alternative to ordinary rocket, and it hasn’t bolted at all during the summer months, even in the heat that we’ve had. It’s different in its bolting pattern to ordinary rocket.”
His team have found that perennial rocket has stayed stronger in the summer months than regular rocket.
“Our conventional rocket bolted in mid-May and we only got one cut out of it, whereas our perennial rocket is being included in all our salads now, and just seems to be happily existing in the hot weather.”
Nine Star broccoli
He has also had huge success with the perennial Nine Star broccoli, a sprouting type, so called because there’s one large central head which resembles a white cauliflower, with multiple cream sideshoots.
“They completely smashed the purple-sprouting broccoli, ordinary broccoli and cauliflower out of the park in terms of how much we were producing,” he says. “We were giving Blenheim about 30 kilos of that a week throughout March and April.
“It tastes exactly like ordinary cauliflower or broccoli, but maybe with a slightly stronger brassica flavour that you might associate with kale, turnips or cabbage. It’s that mild mustardy flavour. ”
This heritage variety will overwinter to produce crops for three or four years before the plant begins to decline, says the RHS.
You need to pick all the shoots or they will run to seed and die, he warns, so be thorough with your harvesting.
Salad burnet
The leaves of this evergreen herbaceous perennial offer a mild cucumber flavour all year, and it will survive down to -23C, growing well in pots and garden beds. It’s ideal for salads, but can also be added to sauces, soups and herb butters.
Sorrel
“It’s similar in texture to spinach but has a really fresh zingy citrusy flavour, it almost tastes like a green apple or a lime, and it’s super high in vitamin C, so if you wanted to make a juice out of it, it’s incredibly nutritious and healthy.”
It can be grown for cut-and-come-again leaves to add to a mixed salad and is best harvested regularly to encourage a steady supply of fresh, young leaves.
“It’s one of these things that will be abundant most of the time in the year without really having to do very much to it at all.”
Do perennial veg need protection in winter?
“No – you can just kind of chop them down to ground level a little bit like you would artichokes, which are a common perennial vegetable. They naturally fall over at the end of the year and then you might cut them down at the base and they will regrow from the base.”
What about flavour?
Some perennial veg taste different from their more recognised annual relatives, with a slightly more bitter flavour, but your palette soon adjusts, says Fannon.
“The perennial vegetables are a bit stronger in flavour and a lot more nutritious. They carry a lot more vitamins in them than annual veg.
“Sometimes they require slightly different cooking. Perennial kale might be slightly tougher but then again you have it every year and it can grow into quite a large plant, which can offer shade for the rest of your garden.”
Fannon is currently trialling Korean celery, which requires patience, a bit like asparagus where you have to wait two or three years for the plant to establish itself before you can harvest it, he explains. “It’s a lot stronger in flavour than ordinary celery.”
Where can you find perennial veg?
A lot of the more unusual ones can be found online at specialist seed companies such as Kings Seeds, Incredible Vegetables and She Grows Veg.
More common perennial veg such as asparagus, globe artichokes and rhubarb can be found in garden centres.