The relative abundance and frequency of problems associated with the 20 most common genera of landscape plants found at an institution in Maryland in 1981. Landscapes were monitored by university scouts.
| Plant genus | % of total plants | % of total problems | % of plants in genus with problems |
|---|---|---|---|
| Quercus | 20.3 | 39.2 | 69.7 |
| Ilex | 19.6 | 2.2 | 4.2 |
| Pinus | 9.9 | 17.4 | 63.5 |
| Acer | 4.9 | 4.6 | 34.4 |
| Juniperus | 4.4 | 0.3 | 2.8 |
| Taxus | 3.4 | 0.0 | 0.0 |
| Rhododendron | 3.3 | 9.1 | 63.2 |
| Malus | 3.2 | 7.5 | 85.4 |
| Prunus | 3.1 | 2.8 | 32.8 |
| Ligustrum | 2.7 | 0.0 | 0.0 |
| Pyracantha | 1.5 | 3.7 | 85.0 |
| Magnolia | 1.4 | 0.0 | 0.0 |
| Buxus | 1.4 | 1.3 | 32.7 |
| Viburnum | 1.3 | 0.0 | 0.0 |
| Salix | 1.0 | 1.8 | 64.3 |
| Abelia | 1.0 | 0.0 | 0.0 |
| Forsythia | 1.0 | 0.0 | 0.0 |
| Cornus | 0.9 | 2.6 | 100.0 |
| Cedrus | 0.8 | 0.0 | 0.0 |
| Tsuga | 0.7 | 0.0 | 0.0 |
| Total | 85.8 | 92.5 |