Raingardens: Everything You Ever Need to Know
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What is a Raingarden?
A raingarden is a water saving garden. You might have seen a raingarden before and not even realized it's a rain garden. That's because raingardens look the same as regular garden beds, but they're designed to capture storm water from hard surfaces like driveways, roofs and courtyards and divert all that water to a garden bed where it can be soaked up by thirsty plants.
Raingardens are a terrific way to save water, reduce water waste and slow down storm water run off which can lead to erosion and pollute rivers, streams and, ultimately the ocean.
"Raingardens are changing the way Australians think about gardening and are rapidly becoming an important part of garden design, particularly in Melbourne. They can even be positioned to capture overflow from a rainwater tank." -- Melbourne Water
Benefits of a Raingarden
The Victorian Government’s Melbourne Water has erected green bus shelters around Melbourne to demonstrate benefits of raingardens and how they work.
Raingardens help filter storm water before it enters our waterways. There are many benefits for both you and the environment of building a raingarden in your own backyard.
Raingardens: - Are self watering and easy to maintain - Are water saving, especially if planted with native, drought tolerant plants - Help to filter storm water before it enters our rivers and creeks - Reduce the rate and amount of storm water that enters rivers and creeks after heavy rain - Make a real difference to the environment and contribute to healthy waterways.
Types of Raingardens
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Planter box: A planter box raingarden is a built up garden just like a regular planter box. It collects storm water via a diverted down pipe and allows the storm water to trickle through the soil and the plants' roots before returning excess water back to the storm water system. This slows down the storm water and ensures it's put to good use before wastefully flowing away.
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Inground Raingarden: An unground raingarden is just like a regular garden bed, but it has a storm water down pipe which flows directly into it as well as a dedicated drainage system to deal with excess storm water that isn't sucked up by the soil and plants.
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Infiltration Raingarden: Positioned at ground level, an infiltration raingarden's job is to collect storm water so it can later soak into the surrounding soil.
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Swale: A slight depression in the landscape which can be either grassed or planted with other vegetation. Designed to slow down storm water and absorb as much as possible before exiting into the storm water system.
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Green Roof Raingarden: That's right, the popular green roof is also a type of raingarden. When the roof of a building is covered in vegetation and soil, it acts as a raingarden, assisting with the filtration of stormwater.
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Downpipe Diversion Raingarden: This type of raingarden is a roof downpipe which diverts roof water through a hose via a d-shape mechanism, allowing water to soak into the garden and surrounding soil.
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Porous Paving: Porous or permeable paving is another way to achieve a raingarden effect. By laying a permeable material - often a brick or paver with intentional gaps, it allows water to soak into the ground rather than running off into the storm water system. This is great for surrounding trees and garden and the health of your soil.
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Rainwater Tank Diversion: Like a a downpipe diversion only the d-shape mechanism is fitted to the overflow of the rainwater tank. Vegetable Raingarden: Even vegetable gardens can be set up as rain gardens. The trick is to make them sub-irrigated. By letting the storm water enter from the base of the garden the vegetables won't becomes submerged and damaged during a heavy downpour.
How to Build a Raingarden
Plus, raingardens are easy to build! They come in a range of types, shapes and sizes, so you can be sure to find the perfect fit for your home. Here is a basic step by step guide to building your own raingarden:
Step 1 – Choose the Right Type of Raingarden
Work out the best place on your site to capture storm water. It could be a down pipe, driveway, patio or even the overflow from your rainwater tank.
Then choose a raingarden type that suits your location. Check out our section on types of raingardens for some ideas.
Step 2 – Build Your Raingarden
This is the fun part. Start by either constructing your planter box or excavating your trench -- depending on the type of raingarden you have decided to build.
If you are building an inground style raingarden (including inground and infiltration raingarden or swale), dig the area with a gentle slope away from the house.
Determine if your raingarden needs to be lined with a PVC liner or if a perforated pipe at the bottom of your raingarden is required. Ensure an overflow pipe is installed to drain excess water during heavy rainfall.
Next, add your sandy soil layers one layer at a time. Have a plumber attach a flow spreader to the end of your downpipe or rainwater tank overflow to evenly distribute water flow into your garden to limit erosion.
At this point your raingarden is almost complete.
Step 3 – Raingarden Planting
There are many plants that are suitable for raingardens. Get creative with your raingarden design. You can use a variety of plants, or all the same type.
Make sure you mulch your plants with gravel to make them as water wise as possible. It's best to avoid bark or straw mulch which might get carried away during heavy rain.
Ask at your local nursery which plants are suitable for use in a raingarden. The best plants will be able to tolerate heavy rainfall as well as dry spells. native plants tend to work best because they are resilient and adapted to our harsh climate.
Step 4 - Get Professional Assistance
If you're not confident with any of these steps, one of our qualified landscapers can help.
Keep Your Raingarden Healthy
Most of the time your raingarden won't need any maintenance at all. If it's planted with native plants you'll probably never have to worry about it. That said, there are a few steps you should take to make sure your raingarden stays in tip top shape.
- Cover your raingarden with gravel mulch to retain moisture.
- Weed your raingarden until the plants have matured.
- Evenly distribute water flow into your raingarden to limit erosion from heavy rainfall. Strategically placed rocks may help with this.
- Inspect your raingarden - replace plants and repair erosion in your raingarden when necessary.
- Don't drive over or squash your raingarden as this will reduce its ability to work effectively.
- If it doesn't rain, water your raingarden until your plants have established in compliance with your local water restrictions.
For more information about raingardens, check out Melbourne Water's great guide.
5 Stunning Examples of Water Saving Rain Gardens
1. Water Tank Rain Garden
A half water tank makes the perfect rain garden.
2. Native Raingarden
Native plants are the best choice for a water wise and healthy raingarden.
3. Vertical Raingarden
Raingardens don't need to be limited to the horizontal plane...
4. Street Raingarden
Even nature strips can be turned into amazing raingardens
5. Modern Raingarden
The Edinbourough Gardens in Melbourne has a fantastic modern raingarden.
Inspired to Build Your Own Raingarden?
Get all the help you need with Service Central's team of qualified tradespeople. Whether you need a plumber to take care of the drainage, a landscaper to help you prepare the garden and choose suitable plants, or a handyman to whip you up a state of the art raised raingarden bed, we've got the best in the industry ready to help you out. Get quotes today and enjoy your new eco-friendly raingarden tomorrow.
About the Author
Brodie Norris runs Lunchbox Architect, a website featuring one exceptional, architect-designed family home every weekday.
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