Is it really a flower?
Flowers often symbolise the seasons. The joyful claret of the poinsettia in the house at Christmas, the woodland glow of a hellebore in spring, and the smiling face of a sunflower in summer.
But, in the cases of poinsettias, hellebores and sunflowers, we have to forget all we think we know about flowers. The beautiful red rosettes we admire on a poinsettia, Euphorbia pulcherrimma, are not flowers, but bracts. Bracts are leaf-like growths, usually small and easily ignored, at the base of flowers and happily they last a lot longer than delicate petals – so our poinsettias can just keep going.
These bracts surround a dense cluster of insignificant flowers, each the size of a nib of a pen, in the centre. The RHS students at Manea School of Gardening recently visited Delamore Young Plants to learn about how they produce over 100,000 poinsettias to a very precise set of specifications and the red sea of these quintessential Christmas plants was marvellous.
Originating from Mexico, they need warm conditions, hence why they are grown here as a houseplant – and why the greenhouses at Delamore’s are nice and toasty!
So we don’t really notice the flowers on a poinsettia; the petals hardly merit a second glance. Hellebore petals are also surprisingly insignificant as the rejoicing colours of hellebores do not come from petals, but sepals.
Sepals, like bracts, are modified leaves which usually protect the flower in the bud. Yet in a hellebore they outshine the far less noticeable, green petals in the centre of hellebore blooms. Being sepals, their colour can last much longer, so again, pretty petals have been beaten at their own game!
Sometimes plants produce noticeable collections of flowers (such as on Buddleja, the butterfly bush) but quite often it is easy to ignore the fact that one head is made up of many flowers.
A sunflower head, for example, is not one flower. It is a collection of tiny flowers – each with an ovary for producing a seed and a source of pollen – and the collection of these flowers is named an inflorescence. This means that the majority of sunflower flowers don’t even have petals!
While flowers and inflorescences are usually bright to attract pollinators – this would be a pointless exercise in the case of wind-pollinated plants. Wind-pollination is found in grasses, sweetcorn and on many trees, such as the silver birch, Betula pendula.
The birch’s catkins are insignificant tassels, ready to catch a chance breeze for pollination, and though they are flowers they are hardly visible from the ground. This explains why many of our trees do not erupt into fragrant blossom, yet they still produce seed.
On the RHS course, we recently visited Elgood’s Brewery Garden and even when most flowers in the garden had finished with the change of seasons, the magnificent tree collection was still a treat. Among the great specimens was the rare weeping holly, Ilex aquifolium var. pendula (the tallest and largest in the county) which is a female plant – so its feminine flowers do not produce pollen. We also saw the towering spire of the monkey puzzle tree, Araucaria araucana, whose flowers are followed by cones, not conventional seed pods.
So the next time you think you’ve found a flower, give it a second glance and you may find something surprising…
Note: Elgoods have a special Christmas Open Weekend, December 5 and 6, with free Brewery tours and free garden entry. Poinsettia plants are on sale now at Delamores retail outlet.
- Manea School of Gardening (RHS Approved centre)
Plant sales on Saturdays 10am -4pm