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What are "Rainwater Gardens?" "Rainwater Gardens" are a storm water management strategy that has been developed by a team of landscape architects and engineers. The gardens are planted swales that help to capture and filter storm water. The plantings are designed to be colorful and attractive, and an asset to the surrounding neighborhood. How are the Gardens Built? The steps in building the Rainwater Gardens include the following: · Ifneeded, a swale or collection area is graded on the site (this would not be necessary in Centerville, as the swales already exist). The gardens are typically 6 to 12 feet wide, and have been a variety oflengths depending on the site-from 30 to 300 feet long. · Existing vegetation is removed or killed with an herbicide application. · Water-tolerant flowers and native grasses are seeded in the garden. These are species that would have been found in wet prairies and meadows in our region. We select colorful species that are attractive to birds and butterflies, as well as people. Typically they are 1-3 feet in height, so they look tidy, like perennial garden plants. · Some projects choose to add 1-2 year old plants to the seeding. The planting flowers and matures sooner with the addition of small plants. The City could choose to add these plants, or provide plants or plant lists to homeowners and allow them to supplement the seeding. If seeding is used, some plants will flower the first year, and the planting will take approximately 3 years to reach full bloom. The planting will look more mature sooner if plants are added. What maintenance is required? The prairie plants are slow to grow in the spring (they know that Minnesota can have some cold spring weather!). Often weedy plants will germinate first and grow above the prairie flowers. We recommend that the planting be mowed once in the spring (usually between June 1 and 15) for the first several years. This should occur when the weed species are about a foot tall, and before they create seeds. The mowing will expose the prairie plants to more light so they can overtop the weeds, and will keep the weeds from seeding and becoming a long-term problem. Ifweeds are a problem later in the first year, the planting can be mowed again around September 1. The planting should be mowed or weed-whipped to a height of 4-6 inches each time. Homeowners may also hand weed some problem plants, though we have found that mowing takes care of common weeds.