Another W.O.W.

We’ve been beating up nurseries over Why-Oh-Why (W.O.W) do they sell things like Scot broom.  Here’s one of my  favorite W.O.W’s from the landscape side (Homeowner division).

Why-oh-Why do people think grass clippings make a good mulch?!  This photo comes from near my home.  The homeowner put the clippings down about two months ago.  All the trees were dark green and healthy before the clippings were put down.  Note how chlorotic the trees in the middle have already become and the dead lower limbs where the trunks were covered.   We’re all for mulch but this ain’t it!

13 thoughts on “Another W.O.W.”

  1. Is the problem that the grass is being treated like a volcano mulch, or is the decomposition of the grass doing something to the root zone?

  2. Maybe people think it’s a good mulch material because lots of books and websites suggest it? (I have a Rodale Organic Gardening book that suggests grass as a possible mulch material.)

    I’ve used grass on my vegetable garden before, and not noticed a problem. Could the problem here be too thick of a layer or grass that has been treated with an herbicide? Or should one truly never use grass as a mulch?

  3. I too have heard from many sources to use grass clippings as a mulch–so much better than sending it to the landfill…

    Is the problem here that the grass is too alkaline for the conifers. Or has the grass been treated with herbicide?

    Are we doomed to use grass clippings only in the compost pile?

  4. I think the clue here is “the trunks were covered.” Grass clippings can become quite compacted and reduce water and gas exchange. If the plant is stressed because of decreased oxygen availability, it will produce ethylene gas. The dieback from the bottom up is characteristic of ethylene production, as is the chlorosis on the higher branches.

  5. i think the problem here is that the mulch wasn’t applied properly. i too am wondering why grass does not make a good mulch. i could see how it might promote insects and fungus a bit more because of it’s composition but at the same time i don’t think it would hold on to as much nitrogen as wood chips do. i thought grass was a great “poor man’s” mulch, myself included.

  6. If you’re mowing correctly (high, frequently and with a sharp blade) there’s really only one good place for grass clippings – and that’s on the lawn! Returning clippings to the lawn not only greatly reduces the amount of time it takes to mow (through not lugging grass catchers back and forth), but the N, P and K they contain can replace one application of fertilizer per growing season.

    Also, it’s just as well that every other white pine in the photo will eventually die as they’re planted way, way too close together. Click on the following link for a look at an approximately 75 year-old white pine in Central New York.

    Maybe a future topic the four of you could explore are privacy planting options other than hedges?

    Keep up the great work!

  7. A couple observations here. The internode growth indicates the trees may have been in the ground for about 4 years. Looking at the surrounding lawn, its weed free. The chlorosis of the second and th
    ird pine are reminicient of wet feet which white pines abhor. Granted the volcano mulching technique probably hasn’t helped, but will it cause such severe response? The flagging of a singe lower branch on the same side of each tree is curious. I think the situation warrents a closer examination, rather than jumping to conclusions. Is it possible that the roots have finally emerged from some unseen below ground “cage” and just hit the big time where no weeds exist? Tis is a flat site and the pic may show actually a slight depression. The construction of the road/drive to the right may indicate a compaction problem? As I said, I believe more investigation is need. I can’t see the grass mulch doing that alone if at all.

  8. I often collected the bags of grass left by the road to use as mulch in my vegetable garden. The plants flourished with the addition of the grass mulch. If I see a mixture of grass and leaves by the road in the fall, I consider this a major find. Our town puts everything in the landfill. I am careful not to apply thickly. Is all that grass or rootball?

  9. Grass clippings alone will mat & compact, making it impossible for water & gasses to move freely. The top layer will look okay, but underneath is likely fungus & even anaerobic bacteria. Add to that the pesticides likely present in that grass … well, I’d have a chat with my neighbor about mulching. Looks like these trees would be better off not mulched at all than like this.

  10. I’ve been in the throes of updating a proposal this week so haven’t had a chance to chime in on the comments. To reiterate, I am as certain as one can be that the decline of the trees is due to application of the grass clippings. It’s a ‘seeing is believing’ thing. The trees were fine beforehand and have gone downhill almost immediately after the mulching. Why? I think Laura B is on target. I suspect the overall decline is root anoxia from matting of the clippings or ethylene production as Linda suggested. The lower branch die-back suggests fungal pathogens are at work. And Laura, this did pose an ethical dilemma, I suspected the clippings would cause a problem when they were put down but I was curious to see how things would turn out.

  11. The premise that matted grass clippings killed the trees root systems is ludicrous to say the least. I used over 100 lbs of grass clipping a week all summer long every year since 2007 with wonderful vegetables,trees and shrubs to show for it!

  12. Lee, are you mulching with the grass clippings or incorporating? If you’re mulching, to what depth? These guys here have about 6″ around the base of the tree. I’m interested in your experience. I have never seen good results with grass clippings as mulch, whether due to matting resulting in poor aeration, temperature build-up from decomposition, pH changes, or just odor. Just seems like mulching in place and returning the organmic matter to the lawn is a better option.

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