Even though xeriscapes have many positive points, there are drawbacks. The most common failure of xeriscape plantings is inadequate weed control. Our rainfall keeps weeds sprouting without natural irrigation, though it may not provide enough water for many other desirable plants.
Weed control is an absolute essential. Combinations of pre-emergence herbicides with adequate mulches or weed barriers will be effective for most weeds. Deep-rooted perennial weeds such as bindweed, whitetop, quackgrass and thistles require specialized treatments.Xeriscapes also fail because of impatience. In this day of instant landscaping, many homemakers have a difficult time waiting for plants to become established. Low-water-use plants tend to grow more slowly and therefore fill in more slowly. Closer plant spacings or adequate water the first few years will help.
A third major cause of failure of xeriscapes is improper design. Xeriscapes must be designed more carefully than other landscapes. If mistakes are made in the design process they will show for many years, and grouping plants by water use, soil type and sun requirements are all essential. The traditional overkill with water, fertilizers, etc., does not work in xerigraphic plantings.