A Guide to Rain Gardens

Rain gardens are good for the environment. They are eco-friendly because they manage runoff from the hard surfaces on your property, filtering out pollutants and sediment that can enter streams, rivers, and the ocean. Typically an intentional mix of sun and shade plants, rain gardens, while visually stunning, can also provide functional solutions to lawn care issues such as soil erosion and soggy flower beds. A rain garden organically integrated into your landscape design will be a curb appeal focal point everyone will enjoy.

What is a Rain Garden?

The purpose of a rain garden design is to alter the flow of runoff from the gutters or hard surfaces, allowing water to soak into the ground slowly, avoiding soil erosion, and reducing the volume of water and the amount of polluted runoff that can eventually find its way into rivers, streams, and oceans.

It can be created by utilizing a natural depression in the ground or digging a shallow hole dug in soft soil. Don’t forget the gutter system – buried downspouts or above ground downspouts can be directed to discharge runoff directly into the garden.

A rain garden is typically divided into three areas – the centre, the middle, and the outer edge. Plants and low-lying shrubs in the centre enjoy wet conditions; vegetation in the middle where runoff begins filtering downward likes a semi-wet environment; and plants on the outer edge thrive on drier soil.

What are the Benefits of Rain Gardens?

Rain gardens are a simple and inexpensive way to improve drainage on your property. The benefits of a rain garden is:

  • Filters out toxins and other pollutants
  • Prevents soil erosion
  • Replenishes groundwater
  • Reduces standing water issues such as breeding mosquitoes
  • Reduces the potential of basement flooding
  • Attracts beneficial insects that eliminate pests
  • Attracts birds and butterflies
  • Increases property value and curb appeal
  • Easy to maintain

Channeling water away from hard surfaces also helps prevent wear and tear on roofing shingles and driveways and pathways from becoming pitted or cracked.

How does a Rain Garden Work?

After it rains, a rain garden fills with water. The water then filters down into the soil, where it’s “stored” in the centre for 24 to 48 hours before it starts to trickle down into the middle and on to the outer edges. The soil of a rain garden of often mixed with sand and other organic materials it increase the efficiency of the filtering process.

Where should I Locate My Rain Garden?

A rain garden should be located in the direct path of the runoff or in a low-lying area where water tends to collect.

To have the most effective impact on your landscaping, it should be situated downhill, away from the foundation – a minimum of 10 feet.

The soil of the location you choose for the rain garden must be absorbent or malleable. If you would like to combine sun and shade plants, ensure that the area will receive sun for several hours each day.

As with any home improvement project that involves digging, check with the BC 1 Call website for information on how to find out whether it’s safe to dig in a specific location.

When should I Build a Rain Garden?

Before building a rain garden consider the condition of the soil. Technically, one can be installed at anytime, excluding winter months when the ground is frozen. The optimum seasons are spring when the soil is easier to dig and the fall to allow trees and plants to establish their root systems before winter arrives.

What types of Plants should I Choose?

Select native plants, flowering plants, grasses, shrubs, and trees – they will be low-maintenance because they have already adapted to the local climate. The following list is a small sample of native plants that are ideal for rain gardens in the lower mainland:

  • False lily=of-the-valley
  • Pacific bleeding heart
  • Red columbine
  • Coastal strawberry
  • Sword fern
  • Pacific nine bark
  • Red-osier dogwood
  • Nootke rose
  • Western red cedar
  • Shore pine

Since there is an extensive variety of native vegetation available, you are sure to find the perfect combination for your rain garden design.

How do I Maintain My Rain Garden?

Rain gardens are generally low-maintenance and easy to care for. Tips for maintaining your rain garden include:

  • Get rid of weeds – ensure that anyone working in your rain garden can tell the difference between weeds and native plants
  • Water a new garden once a week during its first year
  • Skip the fertilizer – avoid using herbicides, pesticides, and fungicides in and around your rain garden
  • Apply mulch when first establishing the garden – then renew as needed
  • Regularly look for debris accumulation, drainage issues (standing water), weeds, invasive plants, and soil erosion