Explore Plants


Ask Mr. Smarty Plants

Ask Mr. Smarty Plants is a free service provided by the staff and volunteers at the Lady Bird Johnson Wildflower Center.

Search Smarty Plants

Can't find the answer in our existing FAQs, submit a question to Mr. Smarty Plants.
Need help with plant identification, visit the plant identification page.

rate this answer
Not Yet Rated

Monday - November 30, 2009

From: Aurora, IL
Region: Midwest
Topic: Rain Gardens
Title: Plants for Bioswale in Illinois
Answered by: Anne Bossart


I have a 300ft by 15 ft bioswale in Aurora, Illinois. What plants would be best used? Is there a percentage of each plant to take into consideration?


What a great project!  A bioswale or rain garden is the ideal marriage of function and form.  It will slow down storm water runoff to allow infiltration of water into the soil.  This prevents erosion, facilitates the removal of pollutants by soil biota and reduces irrigation requirements to adjacent garden areas. On top of these not insignicant benefits, the choice of appropriate native plants will also provide wildlife habitat. Because of your location not far from Lake Michigan, you will find the website Rain Gardens of West Michigan very helpful.

Your area is long and narrow so you will likely be planting a garden that will simulate a stream and bank.  The light conditions will impact whether you are creating a "woodland" or "sunny meadow" stream and control your plant choices.  You have an area that is large enough to incorporate trees and shrubs as well as perennials and grasses. Plant percentages are entirely up to you; you will design this garden the same way you design any other "mixed border" in your garden.

Although your swale will look like a stream and will some times have an (over)abundance of water in it, your plants will also need to be adapted to dry conditions as well.  Fortunately, many plants that can survive in saturated conditions are also able to handle dry and even compacted soil. If it is possible to amend the soil before you begin to remediate compaction, you will have more success as the water will infiltrate the soil quicker.  You need to evaluate your conditions before you select plants to determine how long you actually have standing water.  If the water stands for an extended period, you will want to choose only plants that can tolerate those conditions.

Ultimately, your plant selection will be limited by what is available in your area but our Native Plant Database will be a great starting point. By doing a Combination Search choosing Illinois and Wet Conditions along with your light requirements and plant types, you will find many plants to choose from. You can narrow your choices even further, if you start by clicking on Recommended Species for Illinois and narrowing the search according to conditions.  This will result in a much smaller list of plants that are readily available. There is also a list of recommended suppliers linked to that page.

Here are some choices from that list:


Calamagrostis canadensis (bluejoint)

Carex stipata (owlfruit sedge)

Spartina pectinata (prairie cordgrass)


Asclepias incarnata (swamp milkweed)

Athyrium filix-femina (common ladyfern)

Chelone glabra (white turtlehead)

Gentiana andrewsii (closed bottle gentian)

Iris virginica (Virginia iris)


Cephalanthus occidentalis (common buttonbush)

Physocarpus opulifolius (common ninebark)

Viburnum opulus var. americanum (American cranberrybush)

Small Trees

Alnus incana (gray alder)

Amelanchier arborea var. arborea (common serviceberry)







More Rain Gardens Questions

Pond Plants for Eureka Springs AR
May 16, 2012 - I have a 1 acre pond that we are cleaning up. This area will be used for recreation and fishing. We plan to put native rock around some of the edges and need perennial plants that do well in rocky are...
view the full question and answer

Riverbank retention in VA
March 26, 2012 - I need some groundcover/bank retention for a Virginia riverbank in mixed sun and shade. I want to plant something native to VA. the area is out of the water but subject to occasional (4-5 times per y...
view the full question and answer

Rain garden plants for Ketonah, NY
March 30, 2010 - Rain garden plant selections for lower NY state
view the full question and answer

Expanding clay soils near rain garden
May 11, 2009 - I want to put a rain garden in my yard in central TX (Kyle). My subdivision architectural review committee expressed concerns about the expansive clay soils becoming saturated and possibly shortening...
view the full question and answer

Rain Garden plant for N. Mississippi
March 03, 2010 - Rain Garden Plants for North Mississippi/Mid-South Region. I wish the search parameters included plants which tolerate seasonal flooding and droughts, so that each state might search for its own r...
view the full question and answer

Smarty Plants's Facebook profile Support the Wildflower Center by Donating Online or Becoming a Member today.

Mr. Smarty Plants wants you to be his Facebook friend. Click the Facebook icon to add yourself to Mr. Smarty Plants list of friends.