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8 Common Mulching Mistakes

Jill likes cooking, writing, painting, & stewardship, and studies gardening through MD Master Gardener & Master Naturalist programs.

Note the diseased bark on this sad tree, the victim of a mulch volcano. Sometimes, in desperation, tree roots grow up into the mulch, seeking water.

Note the diseased bark on this sad tree, the victim of a mulch volcano. Sometimes, in desperation, tree roots grow up into the mulch, seeking water.

Want a healthier yard? Stop the mulch madness! Avoid these 8 common mistakes and make the most of your mulch.

1. Avoid Building Mulch Volcanoes

In order to grow, trees need oxygen as well as nutrients, water, and light. What they don't need are suffocating piles of shredded bark at their base.

Mulch volcanoes deprive roots of air, prevent trees from getting the water they need, provide a haven for insects and pests, and encourage disease.

So why do people pile so much around their trees year and year, creating mulch volcanoes? Perhaps they like the way a giant cone of mulch looks, or maybe they see the volcanoes as a way to protect tree trunks from weed eater damage.

Whatever the reason, mulch volcanoes are a bad idea. A spread of one to three inches of mulch, however, is a great way to promote tree health.

Mulch should extend out to the tree's drip line. Not only will that protect the trunk from mower and trimmer damage, but it will also eliminate the tree's competition with turf for moisture and nutrients. And it will look good far better than a mulch volcano surrounding a sick tree.

Best of all, a two to three-inch layer of mulch that extends to the drip line will help rather than hinder the tree's growth, well-being, and longevity.

2. Don't Miss the Drip Line

What's a drip line? When it rains, water drips off the tips of the outermost limbs of trees. Imagine drawing around the tree right below those tips. That's the drip line. Most of a tree's small roots are located there rather than at the base of the trunk.

Ah, that's better! A layer of shredded bark two to three inches deep is just right.

Ah, that's better! A layer of shredded bark two to three inches deep is just right.

3. Don't Apply Mulch in Too-Thick Layers

Depending upon their type, loose mulches should be applied in layers one to three inches thick.

Applying almost any mulch too thickly can result in the same problems that occur when plants are "volcanoed."

One-Inch Layers

Lava rock, river rock, stones, gravel and sawdust (aged one year, minimum) should be applied in one-inch thick layers.

One to Two-Inch Layers

Spread compost and grass clippings in layers of one to two inches.

One to Three-Inch Layers

Wood chips (aged one year, minimum) are best applied in layers from one to three inches thick.

Two to Three-Inch Layers

Shredded leaves, pine needles and shredded bark work best if applied in layers two to three inches thick.

The best mulch around tomato plants? Red or silver plastic sheeting, compost, or nothing at all.

The best mulch around tomato plants? Red or silver plastic sheeting, compost, or nothing at all.

4. Don't Use the Wrong Kind of Mulch

Are you using the right type of mulch?

All mulch isn't the same. Some works best for certain plants.

Like sawdust and wood chips, shredded bark is a poor choice for an herb garden and will cause plants to wilt. Neither should it be used in a vegetable garden.

Types of Mulch

grass clippings

gravel, river rocks, lava rock

compost

sawdust

straw

pine needles

shredded tires

shredded leaves

plastic sheeting

landscape fabric

cocoa hulls

wood chips

Red, silver and/or black plastic mulch are among the best mulches for vegetables, as is a one-inch dressing of compost, particularly around heavy feeders like tomatoes.

Blueberry bushes, azaleas and other plants that grow best in acidic soil benefit from mulches like pine bark and pine needles.

Which Mulch is Best for Your Plants?

PlantBest MulchWorst Mulch

Blueberries

sawdust, compost, pine needles and/or bark

mushroom compost (has high pH)

Herbs

organic matter and/or white gravel

sawdust or wood chips

Small fruits, such as strawberries & grapes

straw, sawdust, shredded leaves, grass clippings, newspaper, compost

 

Azaleas & rhododendrons

pine needles and/or bark

mushroom compost

Tomatoes & peppers

red plastic, organic matter

wood chips, shredded bark

5. Don't Mulch Everything

Mulch really is great. It protects plants, suppresses weeds, conserves moisture and more.

But that doesn't mean gardeners should use the same mulch (such as shredded bark) throughout their landscape.

Not only should gardeners avoid using the same mulch throughout their landscape, but they should also consider leaving some soil either lightly mulched or completely free of it in order to provide a home for ground-nesting bees, which pollinate fruits, vegetables and flowers.

6. Don't Mulch at the Wrong Time

It's best to mulch when the ground is damp. Perennial herbaceous plants (plants that die down in winter & come back up in spring) should be mulched in late fall to protect them from the freezes & thaws of winter.

Brush away mulch from emerging bulbs for healthy, colorful spring plants.

Brush away mulch from emerging bulbs for healthy, colorful spring plants.

7. Don't Use Old Mulch

When spring arrives, mulch that was used to protect plants over the winter should be removed.

Mulch on Bulbs

Mulch on spring bulbs like daffodils, hyacinths, crocus and tulips should be brushed off in early spring after danger of freezing has past.

If it is left on bulbs, their new shoots may be pale or even colorless. They may also break.

Mulch on Perennials

Likewise, brush mulch away from perennial plants. Mulch that's piled heavily on their crowns could lead to rot.

If voles are a problem, avoid mulching the crowns entirely, especially on small fruits like blueberries and blackberries.

8. Avoid Dirty Mulch

Pest-free mulch that does not stink is the best kind to use. Mulch that has a chemical smell (such as sawdust and/or wood chips that have not been aged) should be avoided.

Also, mulch that's teeming with ants or other insects should not be used, particularly if it will be applied around foundation plants or other plants near homes.

Top 10 Reasons to Mulch

  1. Mulch helps soil retain moisture.
  2. It suppresses weeds, especially when used in conjunction with landscaping fabric, black plastic sheeting or newspaper sheets.
  3. It can be aesthetically pleasing, making flowerbeds, pathways, landscaping islands, sidewalk edges and other areas of the garden look neater.
  4. Mulch helps soil maintain an even temperature.
  5. It helps protect plants from cold temperatures and ice damage in winter.
  6. Organic mulches like grass clippings, shredded leaves, pine needles and shredded bark add nutrients to the soil, improving it and increasing its ability to hold moisture and support germinating seeds.
  7. It can slow down water run-off, diminishing the amount of fertilizer, dirt and debris that pollutes waterways.
  8. It slows down erosion.
  9. Because mulch creates space between trees and turf, it reduces damage from weed eaters and lawnmowers.
  10. Organic mulch reduces soil compaction.
stop-the-mulch-madness-common-mulching-mistakes

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

© 2012 Jill Spencer

Comments

Jill Spencer (author) from United States on November 28, 2019:

Glad you could stop by, Louise.

Louise89 on November 27, 2019:

Great tips, thank you!

Jill Spencer (author) from United States on July 13, 2013:

Thanks, W1totalk! Lately, I've been trying to "think outside the bark" a bit more in my mulching for variety's sake. Nice to hear from you! --Jill

W1totalk on July 13, 2013:

Mulch and the various ways in which mulch can be used is extremely important. Great article.

Jill Spencer (author) from United States on September 17, 2012:

Glad to hear from you, seh1101. Good mantra! Thanks for the link. --Jill

Sean Hemmer from Wisconsin, USA on September 17, 2012:

Great hub! I see the mulch volcanoes way too often. I use my own goofy memory device of "Do not pile it - Donut it!" referring to the shallow ring around the tree.

Up vote, and I linked it to the mulch section of my Soil Preparation hub.

Jill Spencer (author) from United States on June 06, 2012:

Hey, daisyjae! So happy the hub was useful to you. Spread the word: Just say NO to mulch volcanoes. All the best, Jill

daisyjae from Canada on June 06, 2012:

I have seen so many people do the mulch volcano, I thought it was a good thing! Glad I read this hub before I did that to my own trees.

Jill Spencer (author) from United States on June 05, 2012:

Hey, savingkathy! Glad the info was of use to you--and that I found another mulch-volcano hater! Take it easy, Jill

Kathy Sima from Ontario, Canada on June 05, 2012:

I found this hub to be very interesting and informative. I appreciate you sharing all of your tips and knowledge about the different kinds of mulch and how they are best used. I don't like the look of mulch vocanoes around trees - I was glad to hear there's a good reason to avoid them, other than aesthetics! Voted up and useful.

Jill Spencer (author) from United States on June 05, 2012:

Thanks for the vote, moonlake. Glad you found the info useful! --Jill

moonlake from America on June 05, 2012:

We mulch but never in our vegetable garden. Just around flowers and trees. Your hub has lots of good information. Voted Up

Jill Spencer (author) from United States on June 05, 2012:

Thanks for commenting, Peggy W! For a couple of years, we used red plastic mulch around our toms and peppers, but ... this year, like you, nothing at all. It was just easier--and I like easy! Glad you stopped by. Take care, Jill

Peggy Woods from Houston, Texas on June 05, 2012:

We use pine bark mulch around our shrubs that like acid like our azaleas, etc. I learned the hard way not to use the same mulch in the small garden area. Now I only use compost or leave it bare. I'm having better results. So...as you say...not all mulch is the same. No tree volcanoes in our yard! Voted up and SHARING.

Jill Spencer (author) from United States on May 09, 2012:

Hey Lynn3! I know what you mean. Putting on layer after layer of mulch--it's sort of like applying more makeup instead of washing your face. Yew!

Lynn3 from USA on May 09, 2012:

Good information. I have to laugh at the mulch madness I see around my area-I just don't undrestand the thoughts behind it.

Jill Spencer (author) from United States on May 09, 2012:

Always great to hear from you, Derdriu. I'm enjoying your recent foray into cooking hubs. I just love to read cookbooks & and enjoyed your savory macaroni & cheese cupcake recipe especially, although I'll probably try making the potato salad first. Take care, Jill

Derdriu on May 09, 2012:

The Dirt Farmer, What an elucidating, enjoyable, excellent write-up on the life and times of mulch! In particular, you do a great job of differentiating between the various organic and non-organic mulches. Also, I like how you break the two groups down further into plant-group specific categories. Additionally, I appreciate the tips about caring for mulches and the plants they're supposed to protect as well as the top 10 reasons for mulching according to proper procedure.

Voted up + all!

Respectfully, and with many thanks for sharing your gardening genius, Derdriu

Jill Spencer (author) from United States on May 08, 2012:

Hey, Maren Morgan M-T! Always glad to hear from you. Glad you enjoyed the hub. Thanks for reading! --Jill

Maren Elizabeth Morgan from Pennsylvania on May 08, 2012:

Good advice here!

Jill Spencer (author) from United States on May 08, 2012:

Hi, bac2basics! Glad you enjoyed it. Thanks for stopping by! --The Dirt Farmer

Anne from Spain on May 08, 2012:

What an interesting and informative article. Thanks

Jill Spencer (author) from United States on May 07, 2012:

@ rebeccamealey--You're so lucky! Pine needles are such an attractive mulch--or maybe it's just that I love that rustic look. Glad you stopped by. Take care, Jill

Jill Spencer (author) from United States on May 07, 2012:

Hello, bythewhat. (I love your name!) Glad you stopped by. Thanks for commenting.

Rebecca Mealey from Northeastern Georgia, USA on May 07, 2012:

What an informative Hub on mulching. You seemed to have covered everything! Pine needles are my favorite mulch, it is so plentiful here!

bythewhat from USA on May 07, 2012:

Nice tips! Its nice reading articals about something that I share an interest in.

Thanks

Jill Spencer (author) from United States on May 07, 2012:

Thanks, RTalloni. I tried to be organized so the hub would be user-friendly and learned a lot while doing the research. Thanks for commenting. Take care, Jill

RTalloni on May 07, 2012:

This is a super guide to mulching. It will definitely help people avoid mulching mistakes!

Jill Spencer (author) from United States on May 07, 2012:

@ leahlefler-- Your neighborhood too? That's what inspired me to write this hub--all the buried trees in our neck of the woods. So sad! Thanks for reading! --Jill

Jill Spencer (author) from United States on May 07, 2012:

Hey, cheapstuff. I agree: gardening's great! Glad you stopped by. --Jill

Jill Spencer (author) from United States on May 07, 2012:

Hi Robie! Thanks for commenting. Grass clippings are fine, so long as you don't use too much, as they are high in nitrogen and may result in leafy tomato plants with little fruit. Also, if your lawn in chemically treated, I would not use the grass clippings from it on any vegetable or fruit crop you intend to ingest. Take care, Jill

Leah Lefler from Western New York on May 07, 2012:

What a fantastic hub! I love the breakdown of which mulch is best for various plants. We use mulch to help stop the spread of weeds and to give the emerging plants a bit of a "blanket" in the spring, when the air temperature can fluctuate wildly. I shudder when I see those mulch volcanoes around the trees in our local parks. Sometimes they pile the mulch 2 feet high around the trunks of our local trees!

cheapstuff from California on May 07, 2012:

This is amazing. A very extensive guide you have put together about mulching. Plants are one of the best hobbies imo, very tranquil and cheap if you do it right.

Robie Benve from Ohio on May 07, 2012:

Great tips, and right on mulching season!

I herd of people mulching tomatoes with grass clippings from mowing the lawn, I wonder what's your take on that?

Voted up and useful.