Best Climbing Plants for Autumn Foliage-Why Leaves Change Colour

What the autumn garden lacks in flower colour is made up for with fiery leaf shades initially on the plants then by carpeting the earth beneath in a dazzling blanket.

Why Leaves Turn Colour Before They Fall

In spring and summer leaves contain an abundance of chlorophyll, the green pigment which traps the energy from sunlight for use in photosynthesis. As the shorter, duller days and cooler nights of autumn approach, chlorophyll production ceases. Any remaining chlorophyll in the leaves breaks down and pigments which have been masked by chlorophyll are able to display their colourful hues.

Carotenoids which are responsible for the colouration in carrots and pumpkins give us the yellows and oranges in leaves. Xanthophylls are the yellow pigments found in dandelions and sunflowers and are also responsible for yellow leaves.

Before leaf fall layers of cells develop where the leaf stems join the branches. These cells block the transfer of water to and from the leaves. Sugars are trapped and anthocyanins are produced in the leaves. These are the pigments which produce blue, red and violet colours.

The duration and intensity of autumn colour is largely down to the weather. The best autumn colour comes with a combination of mild days and cool, crisp nights. This blaze of glory seldom lasts long as the foliage often falls over-night after a severe frost.

The Virginia Creeper is the Most Popular Climber for Autumn Foliage

The Virginia Creeper (Parthenocissus quinquefolia) is the most popular of the climbers grown for their brilliantly-coloured autumn foliage. The name comes from the Greek parthenos, virgin; kissos, Ivy. The specific epithet quinquefolia refers to the leaves, which are composed of mostly 5 leaflets measuring from 2.5 to 10cm long. These are coarsely toothed dull mid- green leaves above, pale and rather glacous beneath. They turn brilliant red in autumn. This vigorous climber can reach a height of 15 metres.

Other Excellent Members of the Parthenocissus Genus

• Parthenocissus henryana (Chinese Virginia Creeper) is only slightly less hardy than the true Virginia Creeper and not quite so vigorous yet still capable of reaching a height of 10 metres and a spread of 6 metres. The dark green leaves composed of 3-5 oval toothed leaflets have conspicuous silvery-white veins which turn a glorious bright red in autumn.
• Parthenocissus tricuspidata (Boston Ivy) is an extremely vigorous plant reaching 20 metres tall with variable, three lobed, deeply toothed bright green leaves often up to 20cm long which turn a brilliant red to purple prior to leaf fall.
• Parthenocissus tricuspidata ‘Veitchii’ gets up to 15 metres high and spreads to 6 metres. The large lush green leaves turn purple and red before they drop.

Growing Tips for Parthenocissus

These vigorous creepers are suitable for growing through large trees and on fences or walls.They all cling by disc-like suckers on the tips of tendrils, but often need a helping hand after planting before they get a grip. A dab of blu-tack to stick the the young stem to the fence or wall will do the trick.

Preferring fertile well-drained soil they are happy in sun or partial shade. Pruning consists of trimming in winter to fit the available space. Do keep the stems clear of eaves, doors and windows.

Vines for Excellent Autumn Leaf Colour

Two species of the Vitis genus are renowned for their autumn foliage:-

• Vitis coignetiae (Crimson glory vine) is very vigorous (20 metres high and 10 metres across) requiring plenty of room to display its large (up to 30cm across) dark green, heart shaped,leaves which turn glowing, rich-red and amber before hitting the deck.
• Vitis vinifera ‘Purpurea’ is the purple leaved version of the common grape vine. It has burgundy-purple foliage all summer with dusty grey leaf tips. The leaves go darker purple colour in autumn. It eventually reaches 8 metres tall with a spread of 3metres.

Growing Tips for Vines

These plants climb by means of tendrils which need support to twine around. They are ideal for growing over a trellis, pergola or fence or against a wall as well as through a large shrub or tree. Fertile well-drained soil in sun or partial shade is required. Winter pruning is the same as for Parthenocissus.

Finally the Climbing Hydrangea

Hydrangea anomala subsp. petiolaris (Climbing hydrangea) is a vigorous, deciduous climber with an eventual height of 15 metres and a spread to match. It clings by means of aerial roots. Thriving in sun or partial shade it does well on a north facing wall. The 11cm long ovate-rounded leaves have heart-shaped bases. The fresh green spring foliage goes dark green in summer then some turn a beautiful yellow and others take on a ginger hue in autumn. Pruning is simply a matter of trimming to keep the shrub within its allotted space.