Thursday December 01, 2005

Urban gardening

This months RHS Garden magazine concentrates on the various aspects of urban gardening.

The first article coveres the myths of gardening in urban areas, that it is a hostile environment to growing things successfully. These myths were dispelled by various unexpected facts. Urban areas can get up to 30% more rain than rural areas and are not dry arid places that people assume they are. Urban areas can also be warmer due to the heat dome that sits over towns and cities ( drive into a town and see your cars outside temperature reading climb). Buildings and tarmac can act as storage heaters soaking up the heat in the day and releasing it at night. This can result in 2-3 degress centigrade higher temperatures and extend the growing season by two-three weeks. Frost risks are also reduced. Buildings and trees can also reduce the effect of wind damage to small plants but as a negative can also tunnel winds into violent gusts between buildings. Pollution is a perceived problem but trees can reduce this by three quarters, even climbers on buildings reduce atmospheric pollution.

The next article discuss green roofs that is roofs on houses that have grass and other plants growing in a specially created living environment. These are popular on the continent where subsidies are offered to encourage their use. Such green roofs can be very useful in the avoidance of flash flooding as they soak up a lot of the rain that falls instead of it going straight into drainage systems. Also heating and air condtioning costs can be reduced as the layer acts lie an insulator.

Another artical discusses the benefits of planting unusual trees in urban areas. Selected varieties can often survive and flourish where native trees do not. This website tells us more.

One of the final main articles was on the conversion of front gardens in cities to parking places for cars. The knock on effect of this being done means the risk of flooding increasing during heavy rainfall as the water has to run off into drains. In extreme heavy rain the sewerage systems have no choice to to pass on this rainwater ( and the pollutants it now has picked up off roads etc) into rivers. This can cause immediate damage to marine life. The alternative to hard paved/tarmaced areas often look more attractive and can increase the resale price of a property. These include gravel or partial paving. This paving can be placed where the wheels of the car will stand. The other areas can be plants with low lying plants which can make the area attractive. Other options are to build pergolas over where the car stands and have plants growing on them to disguise the view of a car parked underneath.