Shade should never be seen as a problem, in fact, it should be treated as a potentially beautiful garden feature
Shade is a valuable commodity in many gardens. When it’s hot, shade makes us feel cooler and indeed temperatures really are lower in shaded areas. In addition, shade provides a wonderful sense of relaxation.
Everyone can benefit from a garden with some shady spots. Children will be able to play outside longer without getting sunburnt. Glare is reduced and for many that means less headaches or eye strain and the chance of skin cancers is lessened. Even family pets benefit if they can find a shady spot to keep them cool on a hot day. Australia truly is a sun burnt country and as such, shade becomes a particularly desirable asset in any garden.
Shaded areas are usually wetter because of reduced evaporation rates, cooler, greener, less colourful and more protected from wind, frost and rain than open areas. Sometimes however, areas under large trees can in fact be drier if the foliage is dense and catches rain water before it reaches the ground.
Shade occurs in gardens for many different reasons. Sometimes it is created deliberately, other times it happens unintentionally. When developing or redeveloping any garden, it is important to understand what causes shade and to consider whether shade is wanted. Sometimes we start out with shade, such as when large trees are left on the property by a developer, or tall buildings cast shadows over parts of the property. Other times we need to create shade by planting trees or building pergolas, fences or shade-houses. Before you build anything on your property, whether a house, shed, garage, or even a garden wall, consider the shade it will create. Whenever you plant a tree you should always think about the shade it will eventually cast and how that will affect the garden around it.
Shade can become a problem
Shade might not be a problem when you start making a garden, but as time goes on a garden which started out as lightly shaded can become very heavily shaded. As trees and shrubs grow, the amount of shade they create increases. Whenever a new pergola, fence or shed is built, more shade is created. As a garden becomes increasingly shaded, plants which were originally growing well in full sun or light shade, may find themselves struggling in much darker conditions. A garden seat which was originally in a warm part of the garden, may end up in a spot which is often too cold to sit in. A window which caught the winter sun and warmed the house, may become covered by a mature tree, turning what was a pleasant sitting room, into the coldest room in the house.
USING SHADE PROPERLY
It is important to recognize both the advantages and disadvantages of shade in a garden; to understand how and where shade is created; and then to develop and use shade to get the best from your garden.
Shade commonly occurs under large trees as they grow, between boundary fences and the house, on the south side of fences, walls, buildings, hedges and so on, where neighbours have planted large trees close to your boundary, under verandahs and pergolas.
ADVANTAGES OF SHADED AREAS
A shaded area, by definition, is a low light section of the garden and when used as a recreation or relaxation area there is less glare and less chance of skin cancer. Plant foliage is also less likely to burn.
As well, plants in shaded areas require less watering because of slower evaporation and they also receive greater protection from wind and frosts.
DISADVANTAGES OF SHADED AREAS
The foliage of plants can be paler and more straggly as it attempts to reach light. Also, a shaded area can get ‘too wet’ under foot and while this might reduce watering requirements, it can increase the chance of plant disease. Mosquitos, snails and slugs also prefer shaded areas.
Other Possible Problems
- Root Competition – Roots from shade trees will often come to the surface under the tree canopy in search of moisture. If the soil is kept moist at a depth of 50cm-1m below the tree, this problem is less likely. To achieve this, avoid frequent, light watering in warmer weather. The ideal way to water a large tree is to pour the water into a deep hole beside the tree. Dig a hole 1m deep and about 10cm diameter. Insert a 1m length of PVC pipe into the hole and fill in around the outside. Water monthly as required by placing a hose into the pipe and letting it trickle slowly to saturate the soil deep below the tree.
- Matting of Roots – Often a dense mat of roots can develop under old shade trees. Once you have this problem, it is difficult to grow other plants in the soil. If existing shrubs and ground covers are struggling, it may be worth trying some hardy shade loving epiphytic plants such as bromeliads which don’t require a loose soil to grow in.
- Smothering – Large deciduous trees in particular can drop huge amounts of leaf litter over a very short period. Twigs, leaves and fruit falling from trees can end up smothering plants beneath. If this is a problem, the only solutions are to grow taller plants under the tree or to spend more time raking up and removing the litter as it drops.If you find a tree is dropping more litter than is normal, it may be because the tree is under stress. This can sometimes happen during a drought, after a storm, or some other freak change in environmental conditions.
- Straggly Growth of Plants – If plants are not getting enough light, they will grow long, straggly, weak shoots with fewer than normal leaves. Regular hard pruning can help keep these plants bushier. However, in the long-term, you are always better to replace such plants with other varieties more tolerant of the shady conditions.
- Fewer Flowers on Plants – Most plants tend to flower less in the shade. Plants which flower well in heavy shade, are few and far between. If you want flower colour in a shaded garden, it is very important to choose your plants carefully. Be prepared to be ruthless and replace plants which are not performing. Plants in general require some bright light to give their best flower displays.
- More Fungal Disease – Fungal diseases which cause spots or patches on the leaves, rotting of stems or fruits, or powdery or dusty growths, are more likely to occur in shaded places. Infected parts of plants should be cut off and burnt as soon as they are detected. Good ventilation or an airy spot will reduce the chances of fungal diseases.
HOW MUCH SHADE
Shade is a very broad term, which can mean anything from dappled light to the dark conditions under a canopy of giant trees in a rainforest. Obviously plants which grow in slight shade might be totally unsuited to the very dark conditions found below dense trees.
Light shade means shading is very mild. Light is reduced, perhaps to the point where there is no glare, but not much more.
Semi-shade means something between heavy shade and light shade. This can occur beneath some trees that provide a dappled effect.
Part-shade means there is shade for part of the day and direct sun for part of the day. The preference is for sun in the morning and shade from the hot midday and afternoon sun.
Full shade means shade all day; that is, never receiving any direct sunlight.
Heavy shade means the shade cuts out most of the light making the area relatively dark. Neither direct light from the sun, nor indirect light which is reflected, reach heavily shaded areas.
Shade can be measured in terms of a percentage of full sunlight. Shadecloth manufacturers often measure shade as a percentage of the light which might otherwise occur. For example, 75% shadecloth creates 75% shade. Shade cloth is also available in different colours.
It is possible to provide shade on a seasonal basis. For example, you can deliberately provide shade when it is most wanted in summer and remove it in winter, when natural sunlight is reduced. This can be done by using deciduous trees, lime/whitewash on greenhouses, removable shadecloth coverings and so on. This way, you can get the most out of your garden, warm up in the sun during winter and cool down in the shade during summer.
KNOW YOUR PLANTS
Plant knowledge is perhaps the most important tool anyone can have for managing shade in a garden. If you can predict how different species grow, in the garden you are concerned with; you can create the level of shade you want by your choice of large plants, and use the right species of lower plants to complement those large ones.
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