Getting to the Root of the Problem with the RHS Advisory Service

A cautionary tale from Hertfordshire shows just how careful we have to be with the siting and choice of trees in our gardens and just how useful the Royal Horticultural Society (RHS) advisory service can be.

A keen gardener and member of the RHS was worried about surface water not draining away from a well kept and maintained garden. He was even more perplexed because the property was a new build.

So with the help of RHS advisory staff and the local council an investigation into the problem led to something of a shock for the gardener. What they discovered was a blocked drain, not with the usual offending matter but with over 45 metres (150ft) of tree root! The offending root belonged to a willow tree nearing a hundred years old and planted two metres from the drain.

Although the house was a new build the drains probably dated back much further but the shock did leave the gardeners wondering if the old saying about tree roots seeking out water was true.

The RHS runs a free advice line for all its members and offers a back catalogue of guidance and top tips on its website. Helen Bostock of the RHS advisory service says that roots down drains is not an uncommon problem, just one many people do not think of.

She said, "There is a misconception that roots sense water - technically this is not the case. Sound drains are not a worry but if there is a hole or a leak then a plant root will reach it, enter the drain and proliferate inside, sometimes for many feet. It is more common in older drains which have not been maintained over the years. We recommend that unsound drains are fixed, your house insurance may require that drains be well-maintained, and that root barriers are fitted if necessary.

"When deciding to plant new trees, check where and how deep your drains run and how far away your new tree will be. British Standard 5837, specifies recommended distances for new trees to be planted from drains. Trees such as willows or poplars are unsuited to most gardens due to their vigorous roots. However, trees and drains interact in unpredictable ways and just because a tree is close to a drain it should not be automatically suspect."

The RHS recommend the following top five trees for smaller gardens -

For more information on tree roots and any other gardening issues visit www.rhs.org.uk/advice. RHS members can take advantage of a free and personal helpline service by calling 0845 260 8000 (Mon - Fri 10am - 4pm)

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