How to grow Tropaeolum speciosum the flame flower

Its common name is  Flame flower because of the bold swathes of red comprising many tiny scarlet flowers. It is a perennial unlike its relative, the Nasturtium, which is a colourful annual.

The striking red Flame flowers look good anywhere in the garden and never more so when grown through evergreens. This combination enhances the contrast between the strong green and red and looks most effective. It also provides summer interest to the evergreen host. If grown in the right place and conditions, it can be vigorous, but it is a notoriously tricky climber to get established.

Tropaeolum we usually see the common annual Nasturtium ( T.majus) illustrated in the central image. This is the lesser known, and lovely perennial variety  called T. speciosum, whose major fault in the plant world is having an unpronounceable name, but is a great climber.

Not for nothing is it also known as the "Scottish Flame Flower" because, although tricky to grow, it sometimes seems to be easier to establish in Scotland.

Ideal growing conditions are acidic soil, and sun, but not too hot, which may be why it grows well in Scotland.  It is hardy down to around -12C as H5 under the RHS Frost hardy classification.

Tropaeolum will grow best with its roots shady in hummus rich soil. I have never pruned my plant because it dies back each winter and although it returns each year, it doesn't get out of hand. In areas where Tropaeolum gets established and vigorous, it can be pruned back in early spring before it starts growing in earnest. T.speciosum has many flowers of a strong, intense red which flower for several weeks in midsummer.

Tropaeolum belongs to that group of plants which likes its roots in the shade and its top in sun.  This is why it is ideal to grow up through other plants. In the right conditions, it is said to be rampant and so it comes with a gardening warning. That said, it has never been anywhere near rampant in my garden and I am happy to plant and grow it, compared to, say Fallopia common names Russian Vine and Mile a Minute plant which I find to be rampant in any garden conditions, although pretty. 

Interestingly, given that the Tropealum is happiest in cooler conditions, during the long hot summer of 2018 the one in my garden barely flowered at all I think unhappy with the dry hot conditions produced that summer.

It is difficult to germinate from seed. The seeds need to be soaked for a day before seeding, and sown into compost and covered with a light sprinkling of grit. Seeds need to be kept cool for several weeks, 5 degrees and can take months to germinate. It can be easier to propagate from a root cutting, or better still buy  a small plant. 

To get it established, ensure it does not dry out and protect from the scorching sun.

If Tropealum is not the climbing plant for your garden, get inspired by the 10 Best climbing plants for your garden.