The Perennial Vegetables That Pay Back More Than They Cost

There is a particular satisfaction in a vegetable that asks nothing of you in March and still delivers in June without being sown, pricked out, hardened off, or transplanted. Perennial vegetables occupy a quiet corner of the kitchen garden that most growers walk past on their way to the seed rack, and that is a genuine missed opportunity. Not because they are miraculous, and not because they will replace the annual beds, but because once they are properly established, they offer a return on effort that no courgette or French bean can match. The catch, such as it is, is that you have to be prepared to wait, sometimes for two or three seasons, before the first decent harvest. For gardeners conditioned to picking salad leaves six weeks after sowing, this requires a small act of faith.

It is worth being honest about the space question, too. Most perennial vegetables are not compact plants. A globe artichoke, fully grown, occupies something approaching a square metre on its own. Asparagus needs a dedicated bed that will remain undisturbed for twenty years or more. These are plants that want commitment, and the kitchen garden that already feels squeezed by the tomatoes and the climbing beans and the three types of courgette you swore you would not grow again may struggle to accommodate them generously. But even a modest allocation, a single bed, a row against a fence, a bold clump in a sunny corner, can produce something genuinely worthwhile.

Globe Artichoke: the extravagant one that earns it

The globe artichoke (Cynara scolymus) has the looks of a plant that expects to be admired, and in a warm summer it is hard to argue with its own assessment. The silvery architectural foliage alone is worth growing it for, but the edible heads, eaten young and braised with butter or shaved raw over a salad, are reason enough to find it space in the garden.

In UK conditions, artichokes are best established from offsets taken from an existing plant in April or May, or from young plants purchased from a nursery. Seed-grown plants are variable and tend to produce their first heads later, so if you are starting from scratch, a named variety is worth seeking out. 'Violetto di Chioggia' is a beautiful purple-headed Italian variety that performs well in a sheltered spot. 'Green Globe' is more widely available and reliably productive in most parts of England. Plant into well-improved soil in a sunny, reasonably sheltered position, water in well, and then largely leave it alone through the first season. You will see foliage but probably no heads in year one. In year two, the plant will begin to produce in earnest.

Established plants need cutting back to the ground in autumn after the foliage dies back, mulching generously with garden compost, and dividing every three or four years when the clump becomes congested. In colder parts of the UK, a light covering of straw in winter is sensible insurance. In a typical Surrey garden, the plants come through most winters without trouble. Each established clump can produce a dozen or more heads in a good season, which over a long summer represents a serious contribution to the kitchen.

Asparagus: the one that rewards patience with interest

If globe artichokes are extravagant, asparagus (Asparagus officinalis) is the long-term investment that quietly compounds. You will not pick a spear in the first year, and only a modest harvest in the second. In year three, the bed begins to pay in full, and it will continue doing so for two decades or more if well managed. There is no annual vegetable that can offer anything approaching that arithmetic.

The practical requirements are specific. Asparagus needs good drainage, fertile soil, and a permanent home. Raised beds suit it very well for exactly this reason: they drain freely, warm up earlier in spring, and can be filled with a deeply worked mix of topsoil and well-rotted compost without worrying about what the native ground is doing underneath. On heavy clay, asparagus will struggle unless raised beds are used or the planting area is broken up and amended seriously before planting.

Crowns, which are one or two year old root systems, are planted in spring into a prepared trench roughly 20-30cm deep, spread carefully over a low ridge of soil, and covered to just above the crown tips. Do not harvest in the first season. In the second year, harvest very lightly: three or four spears per crown at most, stopping by mid-May to allow the ferns to develop and feed the roots. From year three, harvest from late April until the longest day in June, then let the ferns grow freely until autumn.

The RHS recommends all-male varieties such as 'Gijnlim' and 'Backlim' for UK gardens because they do not produce the seed-bearing berries that divert the plant's energy and generate unwanted seedlings around the bed. 'Connover's Colossal' is a heritage variety still widely grown and reliably productive in good conditions. Weed control in the asparagus bed is critical, particularly in the establishment years: once established, the dense root system suppresses much competition, but in years one and two a patch of couch grass getting into the crowns is a serious setback.

Sea Kale: the underused British native

Crambe maritima is native to British coastlines and has been grown as a vegetable since at least the eighteenth century. It fell out of fashion in the twentieth century, probably because it takes a degree of patience and is not available in supermarkets to establish a benchmark for flavour. Its relative obscurity is also what makes it interesting: there is something quietly satisfying about growing a plant that most of your neighbours will not recognise.

Sea kale is grown for its blanched shoots, produced in early spring. The blanching is done by placing a forcing pot, a large terracotta or purpose-made cover, over the crown in late January or February to exclude light. What emerges underneath is pale, tender, and faintly nutty, eaten steamed or lightly dressed. Left unblanched, the plant produces attractive blue-green foliage and large white flowers that are genuinely ornamental.

Establish sea kale from root cuttings (thongs) taken in autumn and overwintered in a cool, frost-free place, or from seed, which is slower. Plant into well-drained, open ground in a sunny position, spacing plants at least 60cm apart. Like artichokes, the first year is establishment only: no harvest, let the plant build root. Year two onwards, blanching can begin, but take it gently and leave the plant to recover fully each season after the forcing is removed.

It is one of those plants that feels like a discovery, even though it has been growing on British shingle beaches for centuries.

Good King Henry: the one that looks after itself

Chenopodium bonus-henricus is an old cottage garden vegetable that fell so thoroughly out of fashion it became almost a curiosity. That said, it is one of the easiest perennial vegetables to grow in the UK, tolerant of partial shade, not fussy about soil, and producing reliably from early spring. The young leaves can be used much like spinach; the shoots, blanched in the same way as sea kale, have a mild asparagus-like flavour. The flower spikes are edible too, lightly steamed.

From my own experience, Good King Henry is useful precisely because it fills the hungry gap in April and May when the annual beds are still getting started and there is not much coming out of the kitchen garden. It dies back entirely in winter and re-emerges dependably in spring without any intervention required. Sow seed in spring, allow the plant to establish without harvesting in year one, and it will look after itself with very little encouragement after that.

It does have an undeniable plainness about it, and it will not stop visitors in their tracks the way an artichoke does. But a plant that requires nothing from you and produces reliably for years is not to be dismissed on aesthetic grounds.

The case for committing to a perennial patch

The honest argument for perennial vegetables is not that they replace annual growing. They do not, and they should not be expected to. The argument is that a small, well-chosen allocation in the kitchen garden, perhaps a quarter of a raised bed for asparagus, a couple of artichokes in a sunny corner, a row of sea kale along a sheltered fence, provides a consistent, low-maintenance return that frees up attention for everything else.

The establishment years are the investment. They require a degree of discipline, particularly with asparagus, where the temptation to take more than you should in year two is real and the consequences of doing so are felt for several years afterwards. But once that patience is banked, the reward is genuine. A bed of asparagus in its fifth year, sending up spears for six weeks in late spring, costs you nothing but a weekly cut and occasional weeding. A mature globe artichoke in July, producing heads faster than you can use them, is one of the more generous things a kitchen garden can offer.

If you are planning any new beds this summer or autumn, it is worth reserving a section now for whatever you decide to try. Asparagus crowns are best planted in spring, but the bed preparation is most sensibly done in autumn, working in compost and checking drainage before the ground closes up. Sea kale thongs are available from specialist suppliers in autumn. And a packet of Good King Henry seed costs very little and asks almost nothing of you in return.