Sometimes, people ignore plants simply because they're common. We see them all the time, even growing by the side of the road, and they sink into our subconscious and simply fail to emerge.

What is sometimes called the perennial sweet pea, or everlasting pea, is a case in point. Lathyrus latifolius is easy to grow, we see patches thriving along sunny roadsides in Britain and in North America, and in gardens it may annoy us as it can be uncomfortably vigorous. But it’s very colourful, very productive, clings to fences or shrubs with its tendrils and is a splendid long lasting cut flower. If it were scented there’d be hundreds of varieties.

It’s been used to control erosion in North America, and its ability to prevent the germination and development of shrubs has led to its planting along utility lines to ensure access remains unblocked by shrubby growth. A variety has even been developed, ‘Lancer’, specifically for practical use. It grows more upright than others, has superior seedling vigor, is a good seed producer and also has a better blend of colours than other mixtures.

In a few parts of the US it’s seen as a noxious weed but, on the other hand, the United States Department of Agriculture provides detailed instructions on how best to sow it and grow it when using it for erosion control etc.

In gardens it can be quite a spectacle, and is lovely clinging to a rustic fence or to a robust old shrub rose (right, click to enlarge). There are three basic color forms – magenta, pale pink and white – but, in his book on sweet peas, Roger Parsons lists ten varieties (plus a number of synonyms) although the names are not now applied with much care or precision, especially with regard to flower size. But look for ‘Blushing Bride’ (blushed white), ‘Rosa Perle’ (pink, above - click to enlarge), ‘Red Pearl’ (magenta) and ‘White Pearl’ (white). And if you come across ‘Wendy’s Joy’, with mauve flowers, grow it and pass it round – although dividing the root is the only way to be sure it stays true.

Lathyrus latifolius also makes a long lasting cut flower, with up to a dozen flowers on a spike, and is valuable in itself and also to fill out bunches of scented sweet peas. The challenge is to control the vigor of the beast and encourage it to produce long stems. Training the stems on wires does the trick and tends to create long straight flower stems which are easy to reach for picking.

So next time you notice Lathyrus latifolius flowering by the side of the road (as in Suffolk in eastern England, below, click to enlarge) remember what a fine garden plant it is and look out for the best varieties.