URBAN FARMER:Most of the vegetable beds have been dug up for the winter but the sweet peas bloom on, writes FIONNUALA FALLON

DESPITE the jewel-coloured dahlias, fiery red nasturtiums and golden helichrysums still flowering brightly within the confines of its old brick walls, autumn has finally arrived in the Victorian kitchen garden.

And so its two gardeners, Meeda Downey and Brian Quinn, have begun busily preparing for the long winter ahead, harvesting any remaining produce and slowly but steadily emptying the large vegetable beds in readiness for their annual mulch of soil-enriching manure.

But while the very last of the walled garden’s potato crop has now been lifted, its sweetcorn plants dug up, its young espalier apple trees carefully trained on bamboos and its crop of old and spent strawberry plants pulled out, the garden’s wonderful wigwams of sweet pea remain untouched. The reason for this, it seems, is not only because their delicate flowers fill the air with a perfume that holds visitors quietly spellbound, but also because Meeda and Brian are determined to harvest their seed.

“We had to send away to England at the beginning of this year to get seed of some of the heritage-type sweet pea varieties that would typically have been grown in Victorian or Edwardian times – ones like ‘Queen of the Isles’ (1885), ‘Painted Lady’ (1731), ‘America’ (19th-Century), ‘Dorothy Eckford’ (1901) and ‘Lord Nelson’ (1907),” explains Meeda.

“Some of them were very hard to find, so our plan now is to harvest and store the seed ourselves over the next few weeks. Sweet peas are annuals that need to be sown each year and this way, we’ll have our own store of seed for sowing early next spring in the glasshouse.”

And so the OPW gardeners have deliberately allowed the plants to set seed over the last few weeks, watching and waiting as the distinctive pods swell, ripen and dry to the palest shade of brown before harvesting them.

But how, I wondered, could Meeda and Brian be certain that the sweet pea seed they’re gathering will be true to type rather than the random result of cross-pollination between two very different varieties? “Because sweet-pea almost always self-pollinates,” Brian says confidently.

Slightly doubtful, I contacted Roger Parsons (rpsweetpeas.co.uk), a UK-based sweet pea expert and the man who supplied the seed to the OPW garden via Meath-based wholesale seed supplier MG Seeds, to check if this was true.

A professional horticulturist, and former RHS judge, Parsons is not only a much-respected member of the National Sweet Pea Society and author of the recently-published Sweet Pea: An Essential Guide, but is also the custodian of a UK collection of Lathyrus species that includes over 1,100 different varieties of sweet pea or Lathyrus odoratus.

“Yes, what Brian is saying is absolutely correct, sweet pea varieties will almost always come true from seed,” he confirms. “So if you save seed of a blue-flowering variety, then that seed will produce a blue-flowering plant. The reason for this is that the sweet pea flower self-pollinates before it opens, so by the time any pollinating insects get to it, it’s already too late.”

Parsons also confirms that it’s very easy to save the seed of sweet pea.

“It’s quite fun to do – you just wait until the seed pods are dry and you can hear the seeds rattling when you give it a shake. But it’s important to catch them before they open, so I pick the pods when they look ripe, put them in a paper bag and then leave the bag somewhere warm and dry (like a glasshouse or conservatory) for a week or so. After that, you can just store them somewhere cool and dry until it’s time to sow them.”

While the sweet pea varieties in the walled garden are being grown quite separately from each other (each on their own individual willow wigwams) Parsons says that problems can arise where gardeners are trying to harvest seed from a mix of different varieties grown close together.

“At least once a year someone will ask me why they ended up with just white-flowering sweet pea, despite the fact that they’re sure they’d harvested the seed from a mix of different colours. The problem is that after harvesting the seed-pods the gardener then hand-selected what they thought was the best-looking, biggest, smoothest and roundest seed, which usually turns out to be the white-flowering types. So when you’re collecting seed from a mix of different sweet pea varieties, look carefully at the seed. They should be a range of different sizes – some big, some small, some smooth, some wrinkled.”

Parsons advises sowing seed of sweet pea anytime between October and February, although autumn sowings are best suited to those with glasshouses and/or milder gardens. “Sweet pea are perfectly hardy down to a temperature of -5degrees, although those sown in late winter/very early spring will need some heat just to germinate. But after that they should be grown as hard as possible (with the minimum amount of heat) to prevent them getting leggy. Just remember to keep them in full sun and give them some temporary extra protection if the temperature does drop below -5 degrees.”

As for his own personal favourites when it comes to the traditional, old-fashioned varieties of sweet pea, Parsons rattles off the names with ease. “First would be ‘Flora Norton’, which has a lovely, pale blue flower, while next is the lovely, bicoloured ‘Cupani’” (This variety is named after the 17th-century Sicilian monk, Francis Cupani, who first sent its seed to Britain). “Third would be ‘Painted Lady’ , while I also love ‘America’ and ‘Black Knight’. But my all-time favourite sweet pea would be the variety ‘Unique’, which has the most wonderful blue flowers.”

And of the 1,100 different varieties of sweet pea that he grows, which, I wondered, are the most sweetly scented? “The variety ‘Albutt Blue’ has the most outstanding scent of them all while ‘Matucana’ is also beautifully perfumed.”

Back in the walled Victorian kitchen garden, the sweet pea flowers’ distinctively heady perfume will soon disappear as the colourful blossoms begin, one by one, to fade in the autumn sunshine. But with the seed now carefully harvested and stored away, Meeda and Brian can safely look forward to enjoying both flowers and scent again.

The OPW’s walled kitchen garden is in the grounds of the Phoenix Park Visitor Centre, beside the Phoenix Park Café and Ashtown Castle. The gardens open daily from 10am to 4pm

Fionnuala Fallon is a garden designer and writer

WHAT TO: sow, plant and do now

Outdoors: sow direct into the ground, to possibly cover with cloches later in the month in cold gardens, or sow in modules for later planting in the ground: Winter lettuce, Broad Beans, round seeded peas, claytonia, corn salad, landcress, spinach, radishes, overwintering onions, fast growing early carrot varieties, oriental greens like Mizuna, Mustards, rocket, and fast growing salad mixes for baby leaves. All of these will benefit from covering with cloches or fleece suspended over hoops later in the month to protect from potential frost and wind damage.

In a greenhouse, polytunnel or large cold frame: sow all of the above along with mangetout Oregon Giant, garlic for a really early crop of big bulbs next year and sugar peas Delikett and Delikata for pea shoots.With a little warmth you can also still sow flat leaf parsley.

Please bear in mind that none of these are hard and fast rules, as the weather is unpredictable and conditions may vary widely in individual gardens – check the website nickykylegardening.com for further details.

Do: Clear/manure/cover empty beds, water young module/container plants, plant up polytunnel with winter crops, plant out any remaining well-established, module-raised plants, garlic bulbs, inspect brassicas for cabbage white caterpillars, continue harvesting/ storing produce, finish planting strawberry runners.