Meet your Chicagoland Stormwater Storage Requirements with a rain garden!

Rain Garden Mulch Options

MulchMulch is a material put down over the soil to help prevent soil compaction, erosion, weeds, water loss, and frost heave.

Mulch is an important part of any garden, but rain gardens add a little bit of difficulty with traditional organic mulches as they tend to wash away.

To be honest, I have not quite figured out a great solution to this problem and have found that each material has its own advantages and disadvantages depending on the situation.

Below I list the pros and cons of using some different mulches in your rain garden.


One thing to keep in mind as you go through these options is that if you install your plants on 1′ centers the aesthetics of the mulch will mostly be hidden by the plants themselves.

Gravel/Rocks


+ Doesn’t float
+ Walkable/Weed-able when wet
+ Prevents compaction
+ Prevents soil erosion
+ Good weed suppression
+ Adds moisture retention
+/- Moderate help against frost heave
Medium/High labor install
Difficult to Weed
Permanent/Non-Organic
Not desirable to some clients

Woodchips


+ Organic
+ Somewhat walkable/weed-able when wet
+ Prevents compaction
+ Prevents soil erosion
+ Good weed suppression
+ Adds moisture retention
+ Strong help against frost heave
+ Mycorrhiza network will help hold some mulch together in time
Low/Medium labor install
Will float initially

Leaf Litter


+ Organic
+ Higher reseeding rate
+ Somewhat walkable/weed-able when wet
+ Prevents compaction
+ Prevents soil erosion
+ Good weed suppression
+ Adds moisture retention
+ Strong help against frost heave
+ Adds nutrients as it decomposes
+/- Still somewhat floats

Nothing


+ Higher reseeding rate
+ No costs
+ No labor
Not walkable/weed-able when wet
Rain compacts soil
Prone to soil-erosion
No weed suppression
No moisture retention
No help against frost heave


Mulching Tips

Regardless of which mulch you choose, I would like to share a few tips I have learned over the years that may help with your mulching experience, and they all include the number 1 interestingly enough.

Mulch 1st
Only 1” of mulch
Only mulch 1 time

Mulch 1st

If you first install small delicate plants on 1’ centers across 200 square feet, you are in for a long afternoon of mulching afterwards.

I did this the first time, and then never again.

By mulching first and then planting through the mulch you will save yourself literally hours of bent-over, backbreaking work, while preventing accidental damage to your plant material in the mulching process.

Only 1” of mulch

I have read recommendations of 3”, 4” sometimes 6” of mulch in some rain garden guides.

I would suggest only putting down 1″ of mulch.

The 1” of mulch you put down will turn into 2” of mulch once you move the mulch aside for your new plantings.

This will be plenty of mulch to obtain the benefits we want from it.

Additionally, if the mulch is organic and floats, the deeper mulching will move around during a rain storm and smoother plants.

Only mulch 1 time

You should only need to mulch one time.

By the third year, your closely installed plants will have filled in enough to supply many of the benefits that mulch delivers in the early stages of the rain garden’s development.

Over this time, organic matter from the plants in the rain garden, as well as from surrounding leaves being blown in, will have begun to create a layer of organic matter that will continue to supply the benefits that the original mulch began.

You may need to touch up certain places during establishment, but there should be no need to redress the entire garden.


And that’s it.

Your basic rain garden design is complete!

You have now completed the designing of your basin dimensions, plant selections, conveyance system, overflow outlet, and mulch.

Congratulations! It can be a lot of work, especially the first time.

Now that you have your basic requirements met, you can decide if there are any additional landscaping elements you want to include in your garden; maybe a gravel or brick path, a small wooden bridge, or even some other plants that you want to include around the rain garden in some way.

The possibilities really are endless as long as you have your basic requirements met.

Be sure to design big because these plants will grow large and really overtake any small elements in a couple of years.

This series will continue to be added to with Special Design Considerations that I come up with over time.

Below you can find a listing of these posts.
Hillside Rain Gardens
Turf as an overflow for your Rain Garden

But if you are all done with your design process, we can continue on to my Build Section which will cover some general information on how to build your rain garden.

Thank you for reading, check back soon!

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