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Why plants climb
Climbers have evolved as plants pushed upwards through the forest or shrubby undergrowth towards the light.
Techniques for climbing differ but all climbing plants used another plant as a support as it strove to reach the light and to hold a place where few other plants can compete with them. It is natural (but sometimes frustrating for the gardener) that these plants flower in the light, right at the top of the plant, with long, leggy growths below.
Thus most climbers are fast growing, and their long, usually supple growths find support before leaves form and the plant becomes heavy and the stems thickens.
How plants climb
Twiners
Twining vines wrap themselves around the host.
Curiously twiners twine in either a clockwise or anti-clockwise direction - and the direction is specific to each species. The growing tips of twining plants make a wide circle to increase the chances of making contact with a potential support.
The higher a twining climber goes, the more closely it holds its support. New Zealand's Tecomanthe speciosa and wisteria are twiners. | |
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Climbing vine | |
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How plants climb
- Twining vines wind
- Hooks, spines or prickles grasp
- Tendril climbers - stem, leaf and leaf stem or petiole tendrils
- Adhesive discs attach
- Adventitious aerial roots attach
- 'Scandent' plants 'throw themselves' over the host
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Clematis are twining climbers | |
Other climbers have hooks, spines or prickles that attach to the host and enable the plant to pull itself up and scramble towards the light. Roses climb by this method.
Tendril Climbers
Tendril climbers have specially modified organs that grasp the host or support. The tendril clinging to smaller objects than twining climbers- the wire netting on your fence, a twig on a host plant. The central stem then grows upwards before developing more tendrils to establish an anchor to the support.
Tendril climbers fall into three groups. Stem tendrils grasp the host as the stem lengthens and the twining action will bring the plant close against the host. These tendrils are often 'spring-loaded' and sensitive to touch as in the passionflowers.
Leaf tendrils are a modification of the leaflets of compound leaves, the commonest example being a sweet pea, where the terminal leaflets are modified into tendrils.
A third type has no tendril but the leaf stem (or petiole) twines about and clings to the host - the most well known example being clematis.
Adhesive Climbers
Other climbers have an adhesive disc at the stem tip this holds the plant firmly against its support, as anyone who has tried to remove Virginia creeper (Parthenocissus sp.) can testify. |
Adventitious Climbers
Some climbers produce short adventitious roots from the stem, and these so-called 'aerial roots' cling strongly to the host. The roots can penetrate and open up cracks in a tree trunk or wall and will hold to its support with remarkable tenacity. Ivy climbs in this way.
'Scandent' Climbers
'Scandent' plants are those that 'throw themselves' over other plants and thus are able to climb out above the undergrowth into the light. |
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Twining vines twine in one direction, and cast their growing stems wide to make contact with a support | |
 More Garden Botany
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