GARDENERS these days are mostly responsible people, but this has not always been the case.

In the past plants have been introduced and the seeds have spread and caused real problems in our countryside, especially around our rivers.

The problem has always been that these foreign plants do not have any native species which will eat them. One major problem at the moment is the spread of Japanese knotweed which is almost impossible to get rid of. In the late summer and autumn its small white flowers produce seeds, but it also spreads quickly from its underground roots and stem systems. Its leaves cast a deep shade which prevent native plants from getting to the light and so they die out. The same applies to Rhododendrons which may look nice but no plants can grow under them.

Another plant which has spread from gardens is the Himalayan Balsam. This has alternative names of policeman’s helmet because of the shape of its flowers and also Touch-me-Not.

This is because when the flower heads fade the seeds inside explode outwards especially when touched. The seeds float in water and are soon spread along the riverbanks and these also shade out the native plants.

Modern day gardeners need to be careful they know as much as possible about the plants they are buying.