Bloom sparkles in last of summer sunshine
Nasturtiums are making a great late show of colour at the moment. Although slow to start because of chilly northerly winds, the plants then made great growth with lots of sunshine and occasional showers. It has long been a popular cottage garden flower.
Few flowers grow as fast, capable of growing shoots more than two metres long in a few months. The climbing sorts are the ones mostly seen, climbing or scrambling on banks and fences or retaining walls, and often used to spread out over a gravelled area. It can be grown in containers too and makes a great contribution of late flowers when other basket plants are beginning to tire and cease flowering.
Originally from South America, the flowers are mostly red, orange or yellow with lots of shades of those colours – peach, dark red, salmon and creamy yellow. The flowers are relatively large with five petals, two upwards and three that almost form a lip below. The petals are usually marked with veins of darker colour that act as honey guides for pollinators. In some kinds the colour of the veins is more spread-out and a blotch of colour marks the petals.
The flowers always appear cheery because of the bright colours but also because they generally face outwards to the sunshine. This attracts passing pollinating insects but it makes the flowers more decorative too.
Nasturtiums are very easy to grow. The seeds are large, about pea-sized, and are simply sown where they are to grow and flower, or they can be sown in individual small pots and planted out in early summer. They are ideal for children to try – easy to sow, quick to germinate and grow, and flower rapidly. The flowers and leaves are edible, peppery to taste.
They are not hardy and flower for just one summer. The leaves and stems collapse with the first severe frost of autumn, but that is not usually until sometime in October. Although the plants collapse and wither, there are usually plenty of seeds shed.
Remarkably, the seeds survive the frosts of winter because they have a corky covering that helps to insulate them, and they almost invariably sprout the following year. Each plant produces many seeds and it only takes a few to re-create the show of summer colour. Nasturtiums are generally trouble-free but can be attacked by greenflies or caterpillars of the cabbage white butterfly.
Do not over-feed as this can cause leafy growth and reduced flowering.