Rain Gardens: Answering the Rallying Cry, “Slow it, spread it, sink it!”
With climate change, we are seeing more rain coming at one time, more massive storms, more extended storms, and more frequent storms. Damage to homes and landscapes is increasing and it demands proper attention to our landscape design. And we know these past two weeks have been especially challenging for those of you facing flooding problems.
That’s why, especially for us living along the lake, we need to think about how we manage water on our property. Whenever we do landscape designs, we take your drainage issues into consideration. And, we’ve done plenty of drainage projects, which much like getting a new roof, is vitally important but not so glamorous. As we increasingly build and add more hardscapes and pavement to our communities, we need to offset those changes with solutions that are environmentally beneficial.
One solution is to install a rain garden or dry creek bed (or both) on your property.
Rain gardens help solve your own drainage issues and help protect your community from its own flooding and drainage problems. Plus, here are way more perks to think about:
- Provide a valuable habitat for birds, butterflies and beneficial insects by using native plants that also help beautify your home and neighborhood
- Increase the amount of water filtering into the ground, which recharges our local and regional aquifers
- Help protect streams and lakes from pollutants carried by stormwater, such as pesticides and fertilizers
How Does a Rain Garden Work and How Big Should it Be?
After a storm, a rain garden is designed to slowly filter rainwater into the ground keeping it from immediately running off into a storm dra in. The size of your garden depends on how much water you want to filter.
A good rule of thumb is for a rain garden to be twice as long as it is wide. You want the garden to catch as much water as possible and be level so that water doesn’t pool at one end and spill over before it has a chance to infiltrate.
The size also depends on how much money you want to spend, how much room you have in your yard and how much runoff you want to control.
Typical residential rain gardens range from 100-300 feet and a good depth is between 3 and 8 inches. Identify your soil type to determine what the ideal depth is for your garden. Sandy soils have the fastest infiltration, clay soils have the slowest. Therefore, sandy soils can tolerate smaller rain gardens.
The shape is also important. You want to shape the garden in a teardrop or kidney shape with a flat bottom (being level is important) and sloping sides; sort of like a pie tin to keep water in the garden.
Where Should a Rain Garden Go?
The key is enjoying the benefits of your rain garden while it does all the hard work for you. Ideally, it would be about 10 feet from your home and near a spot, like your patio, where you can enjoy it. You also want to put it in a gently sloping area with 6 or more hours of sun, and not in an area where water already ponds. If water is ponding, that means it’s not soaking into the ground and your garden won’t filter the water as intended. If you have an area where water is ponding, you might consider a dry creek bed.
This photo is of a client’s flooded back yard before we installed the drainage system and the rain garden to alleviate their extensive flooding issues.
Bonnie told me they had so much water in their back yard that ducks would come and swim in it. In this case, they had standing water for weeks.
Now, even after a huge rainstorm, water infiltrates within a day. For the full story and how the yard looks after installing the rain garden and drainage system, click here.
Rain Garden FAQ
- Do rain gardens form ponds? Nope. They are designed to infiltrate water in a day.
- Are they a lot of maintenance? Once established they should be just a matter of thinning or replanting bare areas as needed, and if using native plants, then low maintenance.
- Are they breeding grounds for mosquitoes? No. Since water is designed to infiltrate within a few days, mosquitoes don’t have enough time since they need 7-12 days to lay eggs and hatch. Rain gardens attract dragonflies, which love to eat mosquitoes, so that’s a win-win!
Components of a Rain Garden and Choosing the Right Plants
A rain garden has three different planting areas: the top of the berm, the basin, and the inside slope. Each area requires slightly different plants. For example, you’ll want plants with the highest wet-soil tolerance in the center because they’ll stay submerged as your plants on the edge will drain fairly quickly.
We highly recommend you use native plants whenever possible for their low maintenance benefits. They require little to no watering in between rainfall and cut down on the need for harmful pesticides (not an issue for our Greenwise customers who know we never use harmful pesticides!).
Select a variety of plants for seasonal and visual interest and cluster individual species in groups of 3-7 to make a bolder color statement. You might think about including sedges and grasses with your flowers, so plants follow their normal growth patterns and don’t outcompete each other.
When mulching your garden, use hardwood mulch to last longer and stay in place. Other types of mulch are too light weight and will wash away easily.
Here are some of our proven natives for rain gardens in our area:
Aronia ‘Brilliantissima’ (Red chokeberry)
- A tall, multi-stemmed native shrub with abundant white flowers, red glossy berries, and outstanding red fall color
- Tough, dependable plant with three-season interest, especially in shady, wet sites. It works well in a naturalized landscape or garden
Carex grayi (Gray Sedge)
- Gray sedge grows best in moist fertile soil in full sun but will tolerate light shade. It thrives at or near water
- Water: Medium to wet
- Maintenance: Low
Carex squarrosa (Squarrose Sedge)
- Adapts to light shade or partial sun, wet to moist conditions, and soil containing loam, silt, sand, or gravel
- Shallow standing water is tolerated if it is seasonal and temporary, rather than permanent
chelone lyonia (Pink turtle-head)
- Pink turtle-head is a glossy, deep green plant with uniquely-shaped pink to red flowers
- blooms in late summer or early fall
- Tolerant of wet sites and some flooding
lindera benzoin (Spicebush)
- Spicy, fragrant leaves and stems
- native to moist woodlands in the Midwest
- It is most often used in landscapes in shrub borders and naturalized areas
Vernonia fasciculata (prairie ironweed)
- Bloom Time: July to September
- Bloom Description: Purple
- Sun: Full sun
- Water: Medium to wet
- Maintenance: Low
Eutrochium purpureum (Joe-Pye weed)
- Bloom Time: July to September
- Bloom Description: Mauve pink
- Sun: Full sun to part shade
- Water: Medium
When to Use Dry Creek Beds
Dry creek beds are great on their own or in combination with a rain garden to help filter water. If your property has low areas that tend to hold water, dry creek beds are a great solution. You can also use them to create an area for water to drain to, which will protect the rest of your property from standing water.
The other advantage to dry creek beds is that they typically require less excavation than some other drainage solutions.