Can’t wait for spring to get growing? Try the versatile, fast-growing cup and saucer plant

How was your January, did you brave the cold to sow something? I didn’t. But that’s because I made a vow several years ago not to sow seeds in January as it is not the best use of my time. Most things only really get going once the days get longer – of at least equal length to the nights, meaning around the spring equinox on 20 March. Sowing before then, for me at least, means lots of little trays of soil on resting on windowsills and propped under windows on boxes – fussing at a time when I want to be as unfussy as possible.

There are, however, a couple of plants that break this rule. Nicotiana is one – for the scent come summer – but even more compelling is Cobaea scandens, a superfast climber (scandens means “staircase”) that delivers cut-worthy flowers for months on end. I have rarely been more grateful for the actions of my former self than when marvelling at the fat purple flowers merrily blooming in a sycamore tree, three metres above where it had been planted. I’d sown them nearly a year before – it was the middle of December.

The common name is “cup and saucer plant”, but like “money plant”, the phrase is used for all sorts of different flowers, so for me Cobaea scandens stays in Latin for ease. They bloom in deep, Quality Street purple from fat green buds, or a cool, sometimes purple-streaked white depending on the variety you choose. Cobaea scandens f. alba covers the arches over the path in Sissinghurst Castle’s white garden, if that’s the kind of plant heritage you fancy.

You can buy them as plants from May onwards, but they really are a doddle to germinate from seed. As evidenced by my December show-off, they are also half-hardy, meaning you can plant the seedlings out before the garden fully explodes if you’re sowing now, or sow direct once the risk of frost has passed in late April and May, depending on where you live. You can give the seeds a head start by soaking them in water before offering them patience: germination can take up to a month.

But good things come to those who wait. Despite their extravagant potential – they can grow up to four metres tall – they make a good container plant, especially if you want to grow up a trellis or a wigwam. They will flower after the sweet peas, meaning you can plonk them in the same (well-fed) pot, or plant them in window boxes for an opulent trailing curtain of purple bell-like flowers. The flowers don’t have wildly long stems but they will last in a vase if you sear the bottom of the stems in boiling water.

Mostly, though, I love the sheer profligacy of them: metres of happy, blooming vine to take over a fence, arch, arbour or unsightly guttering. Your future self will thank you.