Questions Answered Series: Rain Gardens

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How To Plant, Grow & Care For Rain Gardens: Your Questions Answered!

Rain gardens have taken the horticultural industry by storm, no pun intended. These purposeful gardens have become a wonderful and sustainable way to manage stormwater runoff while beautifying your landscape, having both an aesthetic and ecological impact. By collecting rainwater and allowing it to slowly infiltrate into the ground, rain gardens can reduce the amount of water that enters storm drains, which can help prevent flooding and erosion. Additionally, rain gardens can provide a habitat for pollinators and other wildlife while creating charm in your landscape.

Here, Great Garden Plants answers all your questions about designing, planting, and caring for rain gardens.

Beautiful Rain Garden

What is a rain garden?

Simply put, a rain garden is a garden designed to filter rainwater. These gardens are typically planted in a depression where rainwater runs off a roof, driveway, or higher ground. This will help to capture and absorb the rainwater, preventing it from running off into storm drains and potentially causing erosion or pollution. In addition to its practical benefits, a rain garden can enhance a landscape’s beauty and provide a habitat for wildlife, such as butterflies and birds.

Unlike ponds and wetlands, rain gardens only hold onto water briefly, typically draining within 12-48 hours. Creating a rain garden can be as simple as adding a few water-loving (and salt-tolerant) plants to your landscape. Or make it complex by creating a bioretention area! Like anything in your garden, it’s entirely up to you. Later on in this blog, we’ll discuss the plants best suited for rain gardens due to their solubility and water-loving nature.

How do rain gardens work?

Rain gardens filter pollution, keeping fertilizers, pesticides, and other chemicals from drains and local water sources. This happens when storm water flows over the plants and the top mulch, before being absorbed into the soil. Over time, pollutants and nutrients are broken down in the soil. By directing rainwater away from storm drains, ponds, and rivers and into a rain garden, you create a beautiful landscape that works to reduce water pollution. These purposeful gardens also capture and divert runoff from gutters and patios. 

What perennials are best in rain gardens?

There are plenty of perennials that grow well in rain gardens. Generally, they don’t mind having wet or water-logged soils for a short period of time. We don’t recommend planting any pond or stream-loving plants here, as rain gardens shouldn’t stay wet for too long. Explore our full list of rain garden plant recommendations HERE.

Hostas: These shade-loving plants also prefer wet soil, making them a color and compact addition to your rain garden.

Bee Balm: Most commonly found alongside streams and in boggy areas, bee balm is a natural fit. Pollinators will love this rain garden addition too!

Cranesbill: This hardy and highly adaptable plant will thrive in wet soil, making them great rain garden additions. Not to mention, their various purple and blue blooms and tall habit add a whimsical feel.

Phlox: While phlox may require more sun than other rain garden plants, they also thrive in wet soils on sloped landscapes.

Columbine: The dense root system of Columbine makes it able to easily absorb water and manage erosion in your rain garden. Their colorful mix of petals makes them a vibrant addition between hostas and phlox.

Daylilies: Rain garden plants don’t ever need to be dull and drab! Daylilies’ colorful blooms make look beautiful in a cottage or woodsy garden.

Siberian Bugloss: What’s not to love about the heart-shaped leaves and beautiful spring blooms from Siberian bugloss? These plants make great woodland garden additions and prefer moisture-rich environments.

Cardinal Flowers: This moisture-tolerant plant attracts pollinators in troves and has an extremely high tolerance for wet soil. 

Feather Reed Grass: The feathery, light pink blooms from varieties of feather reed grass feels add a nautical aesthetic to any landscape, making them perfect for growing near ponds or streams.

Ninebark: This plant is natively found in boggy areas or along streams, making it a seamless addition to your rain garden.

What shrubs are best in rain gardens?

Whether you want to add a splash of color with flowering shrubs or create a pollinator sanctuary in your rain garden, these shrubs will do the trick! Here is a list of our favorite shrubs that prefer wet or water-logged soils to complement the perennials in your rain garden. Explore other shrubs for rain gardens cultivated by Proven Winners ColorChoice Shrubs HERE.

Dappled Willow: Dappled willow adds multi-season interest to the rain garden. Its tri-colored foliage turns heads from spring through fall, with red stems adding winter interest.

Summersweet: This native shrub does best in shady environments with moist, even wet soils. Where it grows wild, it is often found alongside rivers and streams, making it a perfect addition to the rain garden!

Viburnum: Viburnum is a shrub that has it all! Sweetly scented flowers emerge in spring, then give way to stunning foliage and berries come fall. This shrub grows in any moist soil and occasionally tolerates wet areas.

Buttonbush: If you want to add pollinator value to your rain garden, look no further than buttonbush! This native shrub is a magnet for bees and butterflies, who can’t resist landing on their sweet spherical flowers.

Aronia: The low-growing mounded habit of aronia is excellent for adding structure to your rain garden or creating a pathway near a body of water.

Shop our collection of plants for rain gardens:

What is the best spot for a rain garden?

A rain garden is a beautiful and eco-friendly addition to any yard or landscape, but determining where to put it may leave you feeling lost. When designing your rain garden, look for places where rainfall runoff naturally occurs, like near driveways, downspouts, and slopes. You can plant your rain garden alongside these areas or find a spot where the water pools in your landscape. They’re usually small depressions (but not ditches). But be careful! You’ll want to avoid areas that collect too much water and turn into ponds.

Additionally, consider factors such as sun exposure, proximity to trees and other plants, and the size of the garden. Most rain garden plants thrive in full sun or partial shade, so a spot with at least six hours of direct sunlight is ideal.

What are the benefits of a rain garden?

Rain gardens have several positive environmental impacts. One of the most significant is reducing the amount of stormwater runoff. When rainwater runs off hard surfaces like roofs, driveways, and streets, it picks up pollutants like oil, fertilizer, and other chemicals and carries them into local waterways. This can cause pollution, erosion, and harm to aquatic life. Rain gardens capture and absorb this water, allowing it to slowly infiltrate the ground, filtering pollutants and recharging the local groundwater supply.

Rain gardens also provide habitat for wildlife, particularly pollinators like birds, butterflies, and bees. Native plants in the garden supply food and shelter for these creatures, helping to support local ecosystems.

How do you design a rain garden?

Before designing any garden, it’s important to determine its purpose. Luckily, rain gardens are incredibly purposeful and take the “why” out of the equation. Designing a rain garden involves several vital steps to ensure it is aesthetically pleasing and effective at managing stormwater runoff.

Once you have chosen a location, it is essential to consider the size and shape of the garden. A good rule of thumb is to make the garden at least 100 square feet or 10% of the size of the impervious surface that is draining it. The next step is to determine the depth of the garden. Most rain gardens are between 6 and 12 inches deep and should have a 2-3% slope to encourage water to flow into the garden. Ensure that the garden is not too deep, which can lead to poor drainage and waterlogged plants.

When choosing your rain garden plants listed earlier in this blog, opt for a mix of grasses, sedges, and wildflowers to provide diversity and create a natural look.

Rozanne cranesbill growing in a rain garden

What zones are best suited for rain gardens?

Rain gardens are well-suited for various climate zones but are particularly effective in areas with heavy rainfall and soil draining poorly. Rain gardens are generally best suited for areas that receive at least 20 inches of yearly rainfall.

Regarding specific climate zones, rain gardens are well-suited for temperate and humid regions, such as the Pacific Northwest, the Midwest, the Northeast, and the Southeastern United States. These regions receive ample rainfall and often experience heavy storms that create runoff.

Find your gardening zone:

What type of maintenance does a rain garden require?

Rain gardens are low-maintenance gardens, but they do require some upkeep to ensure that they remain effective so they don’t warrant any unwanted pests or diseases. Here are some maintenance tasks to consider for a rain garden:

Watering: During periods of drought, it may be necessary to water the garden to prevent the plants from drying out.

Weeding: Regular weeding is necessary to keep the rain garden free of invasive species and to allow native plants to thrive.

Pruning: Some plants in the rain garden may require pruning to keep them from becoming too large or to promote healthy growth. Check our “How To Grow” section on every rain garden plant to determine if yours needs pruning!

Shop plants suited for rain gardens from Great Garden Plants:

In conclusion, rain gardens can be an easy and aesthetically pleasing way to reduce erosion and pollution in your landscape. The horticultural experts at Great Garden Plants have assembled a collection of rain garden plants (over 160!) to help you create the rain garden of your dreams. From show-stopping grasses to colorful perennials, there’s a rain garden plant available for your unique setup. Shop rain garden plants for sale:

Written by: Lindsey Griffith, click here to read bio.

Questions, comments, or concerns? Let us know! We have an experienced, knowledgeable staff ready to make sure your garden turns out perfect. Or check out our other blogs, here.