It’s easy to be charmed by a well stocked cottage garden or a rambling rose around the front door, but generally unless you are a particularly keen gardener you won’t give too much thought to the outside space other than noting, for example, that there is space for the kids to play.
But before you purchase a property, it is worth considering a few points concerning the front and back gardens, in particular whether any of the greenery will affect the structural resilience of the property.
Rocking the foundations
Innocent thought they look, there may be some trees and other plants that could pose a danger. The most obvious are trees. Look out for any that are planted close to the building, and be aware that as a rule the root system is at least as large as the branches. Roots can penetrate foundations, causing cracks to your home, and can also damage drainage systems. They are also known to suck the moisture out of the ground during dry periods, causing movement and leading to subsidence.
The trees known most for damaging property are oak, willow and poplars. With these species, it is generally accepted that their roots can extend as far as to two-and-a-half times the height of the tree.
Repairs for root damage can be very costly and may not be covered by your insurance, so make sure that your Chartered Surveyor addresses these issues – the survey should highlight any concerns. If you are particularly concerned, we would advise you obtain a Building Survey (Level 3 Survey), which will provide a detailed report on any structural problems.
Not just trees
A fairly recent threat on these shores is Japanese Knotweed. This is the most invasive species of plant in Britain and spreads extremely quickly. It looks harmless, so beware!
Most of the problems are caused below ground, as it can spread up to 7m in all directions and send up new shoots. It’s capable of forcing its way through concrete, damaging foundations, walls and drains, and is famously hard to get rid of, requiring specialist contractors. It can take several seasons to kill it effectively.
All parts of the plant and any soil contaminated with it are classed as controlled waste and must be disposed of accordingly by dedicated contractors, so it is a serious business. Some mortgage lenders have even been known to withdraw their offer after Japanese Knotweed has been discovered.
RICS has a Japanese Knotweed information paper to provide the industry with the tools to keep assessment and advice consistent across the industry.
Due to increased research into the impact of Japanese Knotweed, RICS have also introduced the 'seven metre rule' into their surveys. This rule maintains that if the plant is properly controlled it does not pose a dire threat to the property and does not need to be completely erradicated by the homeowner. Surveyors will then use their own discretion when assessing they true impact of Knotweed on a property.
Take a look at our guide for what to do if you find Japanese Knotweed on your property.
Climbers
A façade that is clad in ivy, a wisteria dripping with flowers: these can all look delightful. But they can cause damage, too. In particular, English ivy can lift roof tiles, pull away guttering, intrude into mortar joints and may eventually cause masonry to crack. In addition they can cause walls to be persistently damp.
Climbers such as Boston ivy or Virginia Creeper are self-supporting. However, be aware that they can provide a natural ladder for intruders.
Time of year
As well as threats to the fabric of your home, which should be covered by your survey, there are other garden-related issues to consider. Trees can, of course, be beautiful and attract birds and other wildlife. They can provide welcome shade, as well as being useful to screen an unattractive view. But if you are viewing a property in summer, be aware that the tree which provides privacy may lose its leaves later in the year and expose you to your neighbour’s gaze. Viewing in winter, conversely, consider whether the tree may block too much light when it is in leaf.
A sticky mess
Certain varieties of tree (e.g. lime and pine) lose sap (or appear to - sometimes it is actually the secretions of aphids feeding on the trees!). This can cause the garden path or pavement nearby to become very sticky and it may damage the paintwork of any car parked in the vicinity.
Trees that drop blossom or seeds can also clog the drainage and air vents of nearby cars. Fruit trees such as cherry, fig or pear make a slippery mess which can stain. Also, birds seem to develop a favourite spot for perching on to do their business – if your car is parked beneath here this could be a disaster!
Toxic plants
Especially if you have or are planning a family, you will want to be aware that many familiar garden plants are extremely toxic. A single leaf of foxglove can kill a man. Laburnum is another common plant that is dangerous if eaten, and there are many more. Several other plants, such as the many types of decorative and fashionable euphorbia, can cause irritation to the skin. Luckily, in the average family property removing such plants is not too big a job.
Time commitment
When viewing a property with a garden, be realistic about what you can take on or pay a gardener to do for you. Those well stocked borders are going to need a lot of maintenance or they will soon let you down – if you neglect them it will show!
On the bright side
Of course, it’s not all doom and gloom! A lovely garden can give you valuable extra space for entertaining others, growing your own fruit and veg, attracting wildlife, and for the children to play outdoors. If you enjoy the garden and are prepared to put in the effort, the rewards can be great!
For further information, have a look at the Royal Horticultural Society website.
Updated February 2022