Anna Pavord: 'Pennard Plants reveals the unusual fruit and veg we should be propagating'

The Somerset nursery has picked up on a trendy demand for novelties such as oca, New Zealand yams, fruiting fuchsias and Vietnamese coriander

Chris Smith, Hilary the chicken, and Mike Milligan of Pennard Plants (Jim Wileman)

Pennard Plants, near Shepton Mallet in Somerset, has the easy, slightly ramshackle air of the best kind of allotment sites. The nursery, co-owned by Chris Smith and Mike Milligan sits inside the tall, red-brick walls of the kitchen garden that once belonged to Pennard House, just down the road. Polytunnels have replaced the old glasshouses, though the dipping wells still exist, along with some of the original cold frames and remnants of box hedge.

The two-acre site is still intensely productive. And in the cold frames and polytunnels are growing many of the crops that would have been entirely familiar to the tribes of gardeners that worked here in the late 19th century: different varieties of kale, the handsome grey-leaved Babington's leek, old-fashioned herbs such as English mace, hyssop and caraway, different kinds of rhubarb snug under their terracotta forcing pots.

But the Pennard nursery has also picked up on a trendy demand, particularly among those new to growing food, for novelties such as oca, a knobbly tuber confusingly called the New Zealand yam (although it comes from South America) and yacon, another tuber, though less knobbly, from the Andes. They sell goji berries, fruiting fuchsias and a fruiting honeysuckle (Lonicera caerulea) known as the honeyberry. In one of their polytunnels you'll find Vietnamese coriander (larger-leaved and much hotter than the kind we usually grow) and lemon grass. In another, loquats and ugni, supposedly Queen Victoria's favourite fruit – but then she never had to pick the wretched things.

It's an evergreen shrub from Latin America that produces purplish berries – the kind of thing you might usefully include in the understorey if you were gardening the forest garden way, but not the kind of thing you'd want to stand between you and starvation.

I went over to Pennard Plants when the first green was beginning to show in the hedgerows and the primroses were flowering lush along the banks. It was glorious inside the walled garden (open by appointment only), the brick walls soaking up the sunshine and a companionable clutch of chickens scratching about on the manure heap. There I found Fiona Blackmore, who, like everyone associated with the nursery, has spent much of her working life doing something else.

For the whole of the previous day, Fiona had been taking cuttings from Daubenton's perennial kale, so perhaps it's not surprising that when I asked her which of the more unusual plants on the nursery she thought were most worth growing, she put the kale at the top of the list. She'd taken some of the young shoots home to steam for her supper. "Superb," she said. "And what else is there at the moment that you can pick fresh from the garden?"

It's true. And it's why these kales, cottager's kales, acquired names such as 'Hungry Gap'. They are easy, perennial and they produce succulent fresh greens at a time when there's nothing much else fresh to pick, except dandelion leaves. And nettles. The kales get full marks, too, in The Vegetable Garden brought out by William Robinson in 1905. "Very hardy and excellent vegetables," he writes, "often more delicate in flavour than the hearting Cabbages."

The nursery sits inside the tall, red-brick walls of the kitchen garden that once belonged to Pennard House (Jim Wileman)

Flavour is an important criterion for the fruits, herbs and vegetables that the nursery chooses to grow. You pick that up from their website (pennardplants.com) where you'll find the taste of yacon characterised as "a touch of pear or a sweet cross of early apples, watermelon and celery". Turkish rocket, a hardy, long-lived salad green, is described as having a "nutty, pungent, mustardy broccoli flavour". I wasn't surprised to learn from Fiona that Chris Smith is a Master of Wine. They use the same kind of vocabulary.

She'd been taking cuttings of kale, because it doesn't set seed and cuttings are the only way to propagate it. The new shoots (the bits you'd be eating if you had it in your garden) root quite readily and provide the plants that will be ready to send out in 9cm pots to customers in May (£7.50 each). Pennard's also sell a handsome variegated form of Daubenton's kale (£9.50 each), with cream edges to the frilly leaves. Once you've got it, it stays with you, and all you have to do is mulch it each year (all leafy vegetables need plenty of nitrogen) and make sure the plant doesn't dry out in summer.

What else was on Fiona's well-worth-bothering-with list? Oca was next after kale, but success with this depends on the recent run of long, mild autumns continuing into the future. You have to think of them as you might dahlias. You plant a tuber in a pot this month but you can't set the sprouted plant out until late May, because they are tender. Tubers form late in the summer, so if there's an early frost, you won't get much of a crop. But oca is easy and not a vegetable you can easily buy.

"Nutty", "lemony" is apparently what it tastes like (I've not yet tried it), and you can eat it either raw – grated over salad – or cooked. Some say it's best stir-fried, others that you should microwave it.

Fiona's third choice of unusual plants worth trying was the jostaberry (£7.50), a cross between a gooseberry and a blackcurrant, but thornless. The taste of the fruit changes as it ages – gooseberry dominant in young fruit, with blackcurrant taking over as it ages. Like blackcurrant bushes, the jostaberry grows fast – up to about two metres – flowering in mid-spring and producing its harvest by late summer. If you have room for only one bush fruit, this, says Fiona, should be it.

The Pennard Plants nursery at The Walled Gardens, East Pennard, Somerset BA4 6TP is open by appointment. Chris Smith is holding an open day on Thursday, when he'll be demonstrating easy ways to produce food with perennial vegetables and fruit. Tickets cost £25. To book, go to pennardplants.com or call 01749 860039

WEEKEND WORK

WHAT TO DO

* Continue to sow seeds of annual flowers and prick out seedlings that are showing their first pairs of true leaves. I have been pricking out Salvia farinacea 'Victoria' (Suttons £2.99), sown on 10 March.

* Mulch and feed shrubs while the ground is still damp from recent rain. This helps to conserve moisture and will also provide a slowly released reservoir of nutrients.

* Continue to dead-head daffodils, leaving the stem intact to feed goodness back into the bulbs.

* Fuchsias that have been overwintered under cover are breaking into growth now. Gradually increase watering and move them to a place where the temperature can be maintained at about 10C/50F.

WHAT TO BUY

* If you are looking for more unusual things to grow, try cucamelon (Chiltern Seeds £1.80) which look like baby watermelons but which taste of cucumber and lime. Start seeds off as you would cucumbers. Tomatillo 'Verdelino' (Chiltern Seeds £2.45) is a heritage variety from Mexico with striped fruit that hang like little lanterns. To order, go to chilternseeds.co.uk or call 01491 824675.