Mosquitoes need standing water to breed. Even the fastest-maturing breeds require standing water for at least 10 consecutive days. A turf lawn, with its shallow root system, is more likely to be unable to soak up all the water from a heavy rain and have long-standing puddles than a natural landscape with its deeper-rooted native plants. Natural landscapes tend to be planned to take full advantage of native plants whose water requirements match the local rainfall and soils. Natural landscapes also improve habitat for mosquito predators, like birds.
Owners of ornamental ponds in either traditional or natural landscapes can take steps to control mosquitoes. They can keep mosquito-eating fish, float Bt “dunks” (floating, slow-release Bacillis thuringiensis bacteria, which kill only mosquito larvae and not beneficial and harmless aquatic life), or use pumps and waterfalls to keep the water moving.