Rain Gardens are a fairly simple and beautiful way to practice Florida-Friendly Principle # 9 – Reduce Stormwater Runoff. What is a rain garden? Well it is not a pond, nor is it a “water garden.” It can almost be more compared to a municipal drainage retention area, although much smaller and much more attractive.
Rain gardens take advantage of the flow of water in your yard, capture it for a short time, and allow that water to infiltrate the soil and promote aquifer recharge.
Take a look at your yard during or right after a rain event. Where is the water trying to go? Where does it come from as it leaves your yard and becomes stormwater runoff? You are not looking for an existing low spot that already collects water, but you are trying to stop the water that leaves your yard.
If you have downspouts, see where that water travels. Then build a rain garden to stop that water in its tracks from leaving your yard, and becoming stormwater runoff, which is pollutants’ favorite express train to the nearest waterway.
Call 811 before you dig! Phone lines, cable lines, water lines, electric lines – we don’t want to cut any of those! This service will find the line locates for you.
The size and depth of your rain garden will depend on the slope of your yard and the distance from your downspout or other water source. They are rarely deeper than 8 inches, and usually they are around 4 to 6 inches deep. They are usually 10 feet long, but that depends on your soil type and distance from the water source. Sandy soils can have smaller rain gardens and function properly, whereas clay soils will need a larger garden to slow down the water flow. They are usually kidney shaped in design. The high side, the one on which you build a berm with the dirt you have dug out, is facing the uphill slope, so the water flows into the raingarden and stops at the berm and spreads out.
You will want to fill up your rain garden with plants that are happy with wet or dry feet. The water is not meant to stay more than a day or so, usually less time. Some great plants to use in your rain garden would be Muhly Grass, Purple Love Grass, Elliott’s Love Grass, Purple Cone Flower, Rosinweed, Blue Eyed Grass, Coral Bean, Native Milkweeds, Blazing Star, Canna Lilies, Rosemary and others. Utilize The Florida-Friendly Landscaping Guide to Plant Selection & Landscape Design to choose plants. This free publication can be downloaded on line at http://fyn.ifas.ufl.edu/pdf/FYN_Plant_Selection_Guide_v090110.pdf
Look for plants that grow well in central Florida, (Zone 9a.) Look for plants that grow in sunny to partly sunny locations. Look for plants that thrive in dry or wet conditions. Don’t plant your rain garden under or near a large tree. The roots will be a big competition and the tree will shade out your plants. The swale in front of your house may look like a great location, but that is county Right of Way, so stay on your own property.
For specifics in how to build a rain garden, complete with math (eww!) look up Rain Gardens for Central Florida at http://hillsborough.ifas.ufl.edu/documents/pdf/lawn_garden/2010_Rain_Garden_Manual.pdf
You may also email me at LillyB@hernandocounty.us for a pdf version of my DIY Rain Gardens presentation.