Residential rain garden design

Have you heard of a rain garden? If not, it’s time to find out what it is.

A rain garden is a new type of garden that is a great addition to the landscape design. A rain garden is a type of tropical garden arranged in such a way that the structure collects runoff water and allows it to linger rather than soak into the ground. The secret is that the rain garden is filled with moisture-resistant plants.  It’s easy to make, looks great and, importantly, has a positive effect on the environment. What is the peculiarity of the rain garden design? Its main purpose is to collect stormwater from the roof, driveway or other impervious surfaces. Instead of going into a storm drain, rainwater collects in shallow recesses in your yard. This area is specially planted with plants and flowers chosen for their ability to gradually absorb and filter rainwater.

Rain gardens can have a significant impact on your area’s water quality. Studies have shown that up to 70% of pollution in streams, rivers and lakes is caused by stormwater. By taking responsibility for the rainwater that falls on your own roof and driveway, you will help protect our rivers, streams and lakes from stormwater pollution. 

Site placement

Your rain garden should be located at least a few feet away from your home. You should choose a natural area for its placement, which would be the lowest spot in your yard that often collects water after a heavy rain. Ideally, this area should be exposed to sunlight throughout the day. If that is not an option, you can limit it to half of the day, but it should never be a completely shady area. The combination of high humidity and constant shade can turn this area of your garden into a real swamp. 

The site should have a natural slope away from the water gathering area (your roof or driveway). 

Once you have located the new garden, remove the sod and dig a shallow depression of about 10-15 cm. The side slope should gradually go from the outer edge to the deepest area. Use the soil you remove to create a slightly raised area on the underside of the garden. This will help contain stormwater and allow it to slowly seep through the rain garden.

If your rain garden is no more than 15 cm deep, rainwater will be absorbed in about 7 days. Since mosquitoes lay and incubate eggs for 7 to 10 days, this will help you avoid problems with pesky insects. If you want to create an area with standing water for fish and amphibians, you can make one part of your rain garden deeper, up to 50 cm at the deepest point. Depending on the type of soil on your property (sand, clay, loam), you can line the bottom of this area to help keep the pool of water longer.

Most people calculate the size of a garden based on their available space. It depends on the size of the roof surface, the type of soil, and the distance from the rain garden to the house.

The drain from the roof or pump outlet from the basement should point toward the location of the rain garden. This can be accomplished either by a natural slope or by piping along the site.

rain garden

Filling with plants

Any moisture-loving plants will be suitable for a rain garden. They can withstand difficult growing conditions and do not require special care. When choosing plants, consider the height, flowering time and color. Bushes of three or seven plants of the same variety will look better than a patchwork quilt of singles. Be sure to mix ornamental grasses and sedge with perennial wildflowers to provide the garden with a strong root mass that will resist erosion and prevent weed growth.

All moisture-loving plants are suitable for planting in a rain garden, including flowers and shrubs as well as trees.

Flowers and shrubs:

  • valerian
  • geranium
  • periwinkle
  • rush
  • callas
  • globe-flowers
  • merlin
  • turpentine
  • boxwood

Moisture-loving trees include:

  • quince
  • mountain ash
  • hawthorn
  • weeping willow.

Even berries such as blueberries and blueberries can be grown in humid conditions.

Water the newly planted plants every day for the first two weeks. Once they have taken root, your garden can do without watering. Fertilizer will also not be needed. All your care for your rain garden will come down to minimal weeding after the first summer of growth.

Most rain gardeners wait until early spring to remove plants left over from the previous year. If you leave seed heads and fallen foliage over the winter, it provides the garden with a kind of protective roof as well as food for insects. As spring arrives, the best way to get rid of last year’s leftovers is to burn them. Not only will it get rid of the excess trash, but it will also stimulate the growth of new plants.