Mulch: Myth or Magic?

[SuperG]

After another year of no fruit I’m taking the next step and removing the grass from around my trees to put mulch down.

I have a very poor relationship with mulch over the years. Everyone touts it’s moisture retention and weed control properties but I have yet to see it. Weeds grow right up through it, and are provided nutrients via the decomposing wood. Any weed seed that catches the wind or is dropped by birds sets itself to work right fast in the wonderful growing medium that is mulch. Even with weed barriers, weeds find a way. It’s a lot of time and money to put down, and great bedding for mice and other critters. The only ‘clean’ mulch I’ve seen in place over the years is something landscapers have sprayed with a fair amount of weedkiller and that isn’t an option for around fruit trees.

I’m still going to do it, but I’m curious to hear what experiences people have with mulch and how they deal with the weed issue. I’ll start another topic later about how I plant to go about this task.

[Auburn]

The limited mulch I have goes around my blueberries. If I had a low cost supply I would mulch my pears and apples.

[Levers101]

I don’t have so much of a problem with weeds as kentucky bluegrass growing into my mulch.

The beds I have with stone and pavers around them have less KBG invading than the mulch I have around trees, which doesn’t have mulch. But depending on the number of trees you have, this can get expensive fast.

[Susu]

This year I mulched my peach tree for the first time. So I don’t know if it is going to work like magic or not. For veggies I know mulch works like magic. Retains moisture and all the good things they say about it. I normally buy chopped up straw in a bag but this year I’m using fall leaves I collected last fall. I’ve noticed a lot more pillbugs with leaves as mulch than straw mulch. They normally don’t bother plants but they do eat seeds and emerging seedlings. Destroyed my pumpkin and beans as they were poking through the soil. So I guess what you use as mulch matters.

[MES111]

@SuperG

I would use wood chips. This is NOT the same as shredded wood chips.

These are more like wood nuggets. Lay down a single or double layer of plain cardboard (not with glossy outer layer, just the old brown cardboard). Three -four inches of chips on top of the cardboard.

The cardboard will choke off the grass underneath and the large wood chips will not give any weed seeds a place to get a foothold. Any weed that finds a nook or cranny to root in can be easily spotted and removed with no resistance.

See the photo below for my results below. Look under the trees.

Mike

[Matt_in_Maryland]

Holy sh*t, Mike. Your place looks immaculate. Bravo, sir.

[Richard]

Mulch: Myth or Magic?

Magic is quite an old word … its origins going back nearly two millennia where it was used to describe early machines, such as those designed by Heron of Alexandria.

[Richard]

The cardboard will choke off the grass underneath

In your climate. In mine, it will only make the bermuda grass mad.

[Chikn]

I keep the ground bare under my trees. Mulch gives voles winter shelter and a place to hide as they girdle my fruit trees. We are over run with those tailless varmints.

[kokopelli5A]

No se. I mulch heavily. Jellyman said it was a good idea all those years ago. I needed the water savings and I had easy access to free wood chips.
There are times when I thought it kept the soil too cool in the spring here in zone 5.
It does seem to suppress weeds, but only if I reapply every year and make heavy applications. The weeds seem to be easier to pull through all that mulch anyway.
Harvestman suggests that fresh wood chips may have mildly allelopathic qualities even if it’s not Black Walnut. I’m thinking that in the future I’ll compost them for a few weeks first.
The cardboard thing worked pretty good at suppressing weeds in a raised bed here in the Rocky Mountain foothills. I never heard anyone trying that for trees.

[alan]

There are different mulches with different assets. There are different weeds that create different issues in different climates.

Woodchips have to be laid very thick, like 4", to stop weeds at most sites without cardboard or something similar underneath. Mikes method relies on a complete weed shutout- continuous mulch. Most of us have mulch circles so weeds establish on the edges and work inward, often with rhizomes. Once these weeds establish they will always battle for a place in the mulch but are easy to pull once the chips have been renewed a few years and created a soft layer of humus under the annual mulch application.

Cardboard usually works if laid down annually- at least adequately as spring weed control is all that is essential. Here it works for a year. Landscape fabric is even more effective underneath, but you need to pull it up every time you add new mulch and place it over the old.

Shredded wood (as opposed to chips out of the arborist’s chipper) mats up and often creates an impermeable weed AND water stopping layer. Landscapers often pile it up against trunks so they don’t have to weed whack the trunks of trees. The shedded water ends up available to them but this can be a problem with young trees with this mulch over their entire rootzone. Then the mulch needs to be broken up periodically to let water through. The literature warns against stacking mulch against the trunks of trees, but it usually doesn’t hurt them- especially with shredded wood because it becomes dry and repels water in time- even in the humid region.

Wood mulch adds a lot of potassium to the soil, which may create an nutritional imbalance (reducing calcium absorption), I believe, but is only possibly a problem with apples subject to corking, IME. Over time it also enriches soil and increases available water a great deal by way of an ever thickening humus layer, which may become a problem in areas where it rains through the season, because it can make trees excessively vigorous in some soils. This has increased the size of my peaches but reduced the brix, apparently- not good. It takes about 10 years of annual application (usually) for this to become apparent.

[VSOP]

Mulch isn’t a myth or magic. It helps, but it’s not a panacea. I put down a layer of cardboard and have an inch of compost and two inches of wood chips (which I grind myself from my chipper/shredded.). That seems to give the best results. Can stuff still grow in from the sides? Yep, but I find as long as you’re semi-diligent about pulling the stuff out that creeps in from the sides every 2nd week or so, you’re fine.

Another option may be glyphosate around the outside, or a flame weeded to torch around the outside. A weedwacker you periodically scalp the ground around the outside might work as well.

I think if you want to do as little work as possible, you might have to do the most work up-front. Till an area to make a raised bed, allow the seeds to sprout, then move to dirt out of there around 6 inches down. Lay down heavy-duty cardboard. Then fill with your mixture of choice and make a raised bed at least a foot high (better two feet) and liberally mulch the top. IME, hardly any weeds get in there, and if they do, it’s easy-peasy to pull them out. Plant your trees in raised beds and I think you’ll get the best “no weed” results. In my raised bed, I get a few generic weeds (very few). I also get some Bermuda grass trying to go up and under but even that is pretty easy to pull out as long as you get it early. And I could always mulch between my beds or put carpet/cardboard down to kill the Bermuda, I just don’t want to. And if you have a non-aggressive grass like fescue, grass incursion shouldn’t be a problem. At that point, a once a month weeding taking about a minute or two per bed would be all that would be necessary.

[Olpea]

I use about 50 or 60 box truck loads of mulch per year on my orchard. I use it because it’s free. I like to use it around young trees because for young trees there are very limited herbicide options. But I generally have plenty of mulch left over to use around older trees.

Alan is correct that some mulches can be allelopathic. From what I understand, it’s the soft woods like pine and julglan species which are mostly problematic. I’ve not noticed any alleopathic problems using it on my peach trees, except perhaps this year on one tree in which the mulch was applied to about a 1’ depth around the trunk (I have a guy that applies the mulch with a skid steer, so it can get a little thick in places.) That tree is showing some dieback.

We don’t have Bermuda grass here, but we do have bindweed, which sort of acts like Bermuda in terms of tenacity and spreading. A good heavy layer of mulch will last on the upwards of 3 years. It will suppress weeds, but will lose its effectiveness as the layer gets thinner.

It’s not a panacea. It does improve soil life and tilth. Sometimes it can hold too much water. It also does keep the soil cooler (which is not bad for peaches, as it can perhaps slow bloom a little bit compared to black dirt. It is bad for tomatoes because it takes longer for them to start growing.)

I know a lot of people have problems with mulch and voles. We have lots of voles here, but I find the biggest attractant of voles is weed cover. An area thoroughly mulched seems to be a repellent to voles in my locale. I don’t think there is enough food around mulched trees (even voles can’t seem to digest straight wood chips). A thick layer of wood chips also seems to be not very conducive for vole housing. They have a hard time keeping their openings from collapsing. Almost all of my vole problems are where the chips are thin or non- existent and there are lots of weeds. I think cardboard under mulch would make an excellent vole dwelling, but not all places have vole issues (especially a lot of backyards) so I can see where the cardboard might be a good idea.

[JustAnne4]

Nice Mike. You def have the ‘Fort Knox’ thing goin on.
What are the ‘T’ shaped structres for? Bird netting?

[alan]

Alan is correct that some mulches can be allelopathic.

This has never been a noticeable problem when I’ve spread it over fruit trees- and I’ve spread fresh chips over probably thousands of them. It is tender annuals that seem to sometimes struggle under fresh wood mulch. It may also be from tied up nitrogen, but I think some woods are toxic enough to harm tender plants because supplementary N. didn’t help.

[alan]

. An area thoroughly mulched seems to be a repellent to voles in my locale.

I find that they like to make homes in woodchips if food is nearby, like when trees are growing in an area of annually mowed meadow. In such areas I protect trees with the white plastic wraps and sometimes even poison or trap out voles.

[Olpea]

Sorry, I was basing my response on Koko’s post. I’m at the orchard now. Here is the tree in question.

Voles act different here. Here are some wood chips we laid down in the last year. There won’t be any voles.

Here is where a tomato start used to be. They eat my starts.

My cell camera is screwing up and not showing the right photos, but I need to get back to work.

[MES111]

@JustAnne4

Yup. There is a 12 gauge monofilament wire running through the T’s made from PVC. The wires are barely visible in the top photo on the left against the sky. The wires run along the length and width of the orchard. The wires are used to support tenting over with knitted bird netting.

Mike

[MES111]

@Richard

“In your climate. In mine, it will only make the bermuda grass mad.”

We deserve something in exchange for Brown rot, Peach Curl, Pear Psylla, Codling Mot, Plum Curcullio, Japanesse Beetles, and all the other fungal rots, bacterial rots, scabs, mildews etc. etc. etc.

I’d trade them all for some Bermuda problems.

Mike

[MES111]

@alan

In 2012-13 ago when I first started the orchard where it is today, I used shredded wood both as a mulch and hoping that it would decompose and amend my verrrry clay soil.

That worked great while the trees got established for two-three seasons and then the wood broke down enough to cause a weeding nightmare. I found that I was using 2-3 hours of my very precious and limited weekend orchard tending time just dealing with the weeds.

The silver lining in last year’s total NO FRUIT scenario was that it gave me time to do the weed fighting by laying down the weed block (5 ounce heavy 10 year, I hope) in the walking rows between the tree rows.

Taking note of the vigor discussions threads over the last two years, I added coarser HARDWOOD chips on the surface in the growing rows beneath the trees expecting and hoping that they will break down more slowly.

It took me all summer (NO ONE TOUCHES MY BABY BUT ME) and immediately I could see that the mulched rows had one one hundreth of a percent ( 1/100%) of the weeds in comparison to the walkway rows that were waiting for the cloth and the growing rows waiting for the chips.

I had to do each row individually including, the landscape timers to hold the chips in place, because the growing rows are raised and mounded and the chips would slide off the cardboard if I didn’t.

The hoped for payoff is this year when I will have more time to devote to the reason we do this stuff in the first place…BRAGGING RIGHTS for our fruits.

As I like to say… " WHY JUST DO IT WHEN YOU CAN OVERDO IT"

Mike