They are an important element in the ecology of many countries, and harvesting the berries is a popular pastime. However, the plants are also considered a weed, sending down roots from branches that touch the ground, and sending up suckers from the roots. In some parts of the world without native blackberries, such as in Australia, Chile, New Zealand, and the Pacific Northwest of North America, some blackberry species, particularly Rubus armeniacus (Himalayan blackberry) and Rubus laciniatus (evergreen blackberry), are naturalised and considered an invasive species and a serious weed.[4]