Poor soil, incorrect maintenance practices, or simply wrong plant selections by a previous owner result in unhealthy or invasive plant materials on some residential sites. All weak and diseased woody vegetation should be carefully pruned or completely removed depending on the type and extent of the problem. Again, improving soil conditions will also help plants grow more vigorously. Plants that are in the wrong location because of improper hardiness or water requirement should also be taken out. Vegetation that is poorly located because of inappropriate sun exposure, soil, or drainage should be transplanted to a better location on the site if possible.
Invasive plants are nonnative plants that aggressively take over a site at the expense of other plants. Invasive plants often exist because they were incorrectly introduced or because of generally poor growing conditions that weaken native plants and permit invasive plants to dominate. One good source of information on what plants are considered invasive on a national basis is the Web site “Weeds Gone Wild: Alien Plant Invaders for Natural Areas” maintained by the National Park Service
(http://www. nps. gov/plants/alien/index. htm). Another excellent source is Native Alternatives to Invasive Plants, published by the Brooklyn Botanic Garden. In addition to identifying invasive plants and what states they are considered invasive in, this publication also provides a list and description of alternative native plants. Additionally, it is advisable to consult a local county or university extension service, botanical garden, or horticultural expert to determine what plants are considered invasive for your particular region. Some invasive plants such as Arborvitae (Thuja occidentalis) and English ivy (Hedera helix) may be a surprise because of their common usage. Even some species of lawn grass are invasive.
All invasive plants should be eliminated from a site, a task that may be more difficult than expected. Unlike typical plant removal or “grubbing,” all parts of invasive plants including their root systems should be cleared away. This may require extra excavation and handwork to do a thorough job. Weeds in established planting areas call for removal by hand as well. Large areas of weeds and invasive herbaceous vegetation may involve the application of nontoxic herbicides.