Skip to main content

Mulch: The Real Scoop

  • Author:
  • Updated date:

Becki has 25 years of experience as a freelance landscaper and loves to share advice with her readers.

There is so much to learn about mulch!

There is so much to learn about mulch!

Mulch Facts

With over 25 years of experience as a freelance landscaper, I've learned a thing or two about mulch. Through trial and error during landscaping, I've found many tips and tricks about mulch. Here are a few facts that might surprise you.

What Causes Mulch to Fade?

Most suburban homeowners would mulch their flower beds every year, even if the mulch they used the previous year was 'guaranteed' not to fade for one year. Why do they do that?

Because it does fade. That's a fact.

What causes mulch to fade, whether it's color-enhanced or not?

  • Sunlight is the number one culprit
  • Moisture is second

Both are beyond our control to some extent. In the case of color-enhanced mulch, water leaches the dye out, which is why it is recommended not to use it if there is a rain forecast in the next 24 hours. The longer it can 'cure' before it rains, the longer it can hold on to some of its color. If you live in a desert and don't get any rain for a whole year, or if you never water anything in your flower beds for a whole year, your color-enhanced mulch might not fade as much, but it is still going to visibly fade from natural sunlight: if not sunlight, rain, and supplementary watering.

Mulch isn't too hard to use correctly.

Mulch isn't too hard to use correctly.

Mulch With a 'Weed-Preventer' Additive

Okay, I admit it, I was very skeptical when this kind of mulch hit the market because I know that mulch itself is a weed preventer. The more inches you apply, the less likely it is that weed seeds can find their way down to soil level to germinate.

Even though I was skeptical, last season I purchased a dozen bags of a well-known brand of mulch with a weed preventer additive for one bed in particular. As crazy as it sounds, just out of a skeptical gardener's curiosity, I dumped one bag of this mulch on a tarp and sifted and sorted through it very carefully by hand to find each and every granule of weed preventer.

There was only approximately one tablespoon of granules in the entire bag. Determined to see if this was the norm, I repeated the time-consuming process on the next bag and the next and the next until I had sifted and sorted each bag of mulch for granules of weed preventer. It was the same for all 12 bags, about one tablespoon of weed preventer granules.

Considering that the same weed preventer sold separately recommends sprinkling 1 ounce per 10 square feet, the one tablespoon of granules in a bag of mulch is half as much as it should be. Good thing mulch is a natural weed preventer to begin with. I'd rather buy my weed preventer separately and put as much down as is directed on the package and know where it's going.

Mulch with a weed preventer additive gets a resounding thumbs-down from this gardener.

Moldy Mulch

There are lots of different kinds of mulches and lots of different things used for mulch. Right now, I want to focus on just a few of the most common icky things that often grow in a bag of mulch or grow on the top of spread mulch. For easier identification for the newbie gardener, I'll stick with the common names. Feel free to Google the common name if you want to learn more detailed specifics.

White Mold on Mulch

The first one is simply white mold. Mulch is often stored for a season or two, and the little holes in the plastic bags for air circulation also allow moisture or rain to penetrate and get inside the bag. Combine moist mulch with the naturally occurring heat that results as some of the mulch inside the bag decomposes, and you've got a perfect environment for white mold to grow. Don't worry; it's not harmful to your plants, although it can be unsightly. You can pick it out by hand or leave it. Usually, the sun will eventually kill it off.

"Dog Vomit"

The next one is called 'Dog Vomit' because, well, that's what it looks like. It can sometimes form on top of spread mulch and starts out looking kind of orangey-yellow. As it matures, it turns a dark powdery brown. The sun will not kill it off. Either scoop it up and dispose of it or bury it deeper in the mulch.

White Fungus in Mulch

Then there are those aggravating little mushrooms that seem to appear by the dozens overnight. Heat and moisture automatically start to decompose wood products, making the perfect environment for a mushroom to grow. Don't waste your time or mulch by trying to pick them out or dispose of them because they will keep reappearing when the conditions are right. The good news is that usually, by mid-day, the sun has killed them off.


Louise89 on November 27, 2019:

Great info, thank you so much!

RetiredGeek on May 02, 2015:

Thanks for this information, very helpful. I had guessed what the "white stuff" was but wasn't sure if it would hurt the plants. The "yellow stuff" I had no clue.

Johng256 on August 13, 2014:

Great, thanks for sharing this article. Really Cool. dcegbkedeebd