What is a rain garden?

Welcome to our new blog series where we will together explore rain gardens – what they are, who needs them, the advantages and disadvantages, and how to install one. In this first article, we will go over some of the basics of what really is a rain garden. 

What Is a Rain Garden? 

A rain garden is a shallow, planted depression in the ground designed to collect and absorb rainwater runoff from roofs, driveways, pavements, and other hard surfaces. Instead of letting rainwater run off these impermeable surfaces and potentially cause flooding, a rain garden slows the flow and allows water to soak naturally into the soil and be absorbed by specifically chosen plants. 

Rain gardens are both functional and attractive. They are typically planted with a mix of deep-rooted native plants, grasses, and flowers that can tolerate both wet and dry conditions. They are often designed to look like a typical garden bed, rather than a pond, and drain within 24-48 hours after rainfall. They can work as an alternative to sinking a soakaway, essentially turning a drainage problem into a landscape feature.  

Rain Garden Basics 

Rain gardens are usually positioned where runoff naturally flows, such as below drainage or at a notably low point in a garden. 

Key characteristics include: 

• A shallow basin shape 

• Reasonably well-draining soil 

• A range of deep-rooted plants 

• Placement away from building foundations 

Size depends on how much runoff you want to capture, or the size of the roof the runoff is from. A small residential rain garden might be as little as a few square meters, while larger properties may install multiple gardens to manage water flow. 

Benefits of a Rain Garden 

Rain gardens provide both environmental and practical advantages. 

• Rainwater control: They reduce runoff volume and speed, helping prevent localised flooding and erosion, rain gardens can absorb 30% more water than standard lawns 

• Water filtration: Soil and plant roots help filter pollutants such as oils, fertilisers, and sediment before water reaches groundwater or streams. 

• Lower infrastructure strain: By absorbing runoff on-site, rain gardens reduce pressure on municipal drainage systems. 

• Wildlife support: Native plants attract pollinators, birds, and beneficial insects. 

• Landscape beauty: A well-designed rain garden adds colour, texture, and seasonal interest to your garden. 

• Low maintenance: Once established, native plant rain gardens often require less watering and care than traditional lawns or ornamental beds. 

In the next article, we’ll look at one of the most important design choices: selecting the right plants and where to place them within your rain garden. 

If you think your garden might be suitable for a rain garden, don't hesitate to get in contact! We would love to start installing these and seeing the impact they have in different gardens.