The salt spread on roads can get into the trunks, shoots and roots of hedges and trees through water spray when cars pass by. Once it melts, the salt water is adsorbed by the roots. The consequences of this can be, amongst other things, poor growth, irreparable damage or even death of the plants.
Typical symptoms of road salt damage are brown branch tips, mainly close to the ground. However, they are not always easy to spot. Water is drawn from the plants, and the leaves often go brown due to lack of moisture, starting at the edges. Road salt acts like over-fertilisation; the plant obtains too many nutrients and therefore the water is removed from it, thus damaging the plants growth.
In order to prevent salt damage, wooden palisades or other barriers can be dug in at the front of the hedge to protect it. This will act as a buffer and ensure the plant doesn't become covered in water spray. Another method of avoiding salt damage is to water the plant copiously when the ground is not frozen.
Measures in case of damage
If salt damage has already occurred, the only remedy is to water copiously as previously mentioned. A thorough shower after the winter also helps the plant to regenerate and to flush out the salt it has absorbed.
Those wishing to permanently avoid problems with salt damage should plant less salt-sensitive hedges and trees. The snowberry, for example, is considered relatively salt-tolerant. Conifers such as the thuja are considered particularly sensitive plants. These react particularly strongly to road salt, so are generally unsuitable to plant if near a main road or footpath.