SNPA Strapline

Invasive Species

PTYB Gardens


Invasive Species and Gardens

Most of our problem invasive species were brought to this country as garden plants. They have since escaped from gardens into semi-natural habitats such as woodlands, heaths and riverbanks. These are relatively unmanaged by man and, where the conditions are suitable, invasive species can rapidly take over.

Much of the National Park is formed of semi-natural habitats, and although the human population density is low, there are many houses and gardens that adjoin or are surrounded by these habitats. Those with gardens in these areas have a special responsibility to prevent the spread of garden plants into the wild. They are in a very different situation to dwellers in urban and suburban areas.

The spread of plants from gardens can happen in several ways:

  • By seed
  • By suckers and layers
  • Through movement of plant fragments along streams and rivers
  • Through deliberate or accidental dumping of unwanted plants.

One of the big challenges is to predict which plants will be invasive. We know that plants such as Japanese Knotweed and Rhododendron are highly invasive. Unfortunately, we generally do not realise that there is a problem until far too late, when the plants are well established. Also, plants can be highly invasive in one habitat but pose no threat in another. If a garden plant starts to appear in the wild, it clearly has invasive tendencies and should not be grown.