Increased plant diversity has often been linked to lower levels of herbivore abundance in a variety of managed and natural ecosystems. Yet, an analysis of data collected from 212 residential landscapes in suburban Maryland revealed significant positive relationships between the number of insect and mite pests in a landscape and the total number of plants and plant species at the site. A series of studies with the azalea lace bug, Stephanitis pyrioides Scott, revealed the following. Lace bugs were exceedingly rare in residential landscapes with high levels of vegetational complexity. Several mechanisms underlying this observation were investigated. Differences in host plant quality and movement of lace bugs associated with immigration and emigration did not explain differences in lace bug abundance. However, natural enemies and alternative prey were more far more abundant in complex landscapes. Not surprisingly, predation pressure and subsequent, lace bug mortality was greater in diverse, complex landscapes. A corollary study found that the addition of flowering plants to a simple planting of azaleas significantly accelerated the extinction of lace bugs cohorts in the patch. From this study and other related ones, it appears that bottom-up forces related to the diversity and complexity of landscape plants alter the strength of top-down forces and their suppressive effect on some eruptive pests such as azalea lace bug. Altering landscape design may be an effective strategy for making urban landscapes more sustainable.