Lord Howe Island has had a small settlement since 1834, and like most places that Europeans have settled, weeds eventually found their way into the environment. Some plants were introduced as food (Cherry guava Psidiun cattleianum), some as ornamentals (Ochna serrulata) or perhaps some were introduced as seeds in bales of hay in the days when the Island had no motor cars and relied on horses for transport and ploughing fields for farming.
Many of these plants introduced to Lord Howe Island are a minor nuisance around the settlement area. However there are a number of introduced plants that have spread to areas away from the settlement and pose a threat to the long-term integrity of the native forest. The 1997 review of World Heritage values of Lord Howe Island identified weeds as the major threat to the conservation of the Islands unique flora and fauna.
Lord Howe Island has seventeen weed species listed as noxious. These include two species of “Asparagus fern” – Climbing asparagus (Asparagus plumosus) and Ground asparagus (Protasparagus aethiopicus) as well as Cherry guava (Psidium cattleianum), Sweet Pittosporum (Pittosporum undulatum), Bitou bush (Chrysanthemoides monilifera ssp.rotundata) and Madeira vine (Anredera cordifolia).