Mulch Ado About Mulching

Being currently in the early stages of collaborating with my son on the creation of several planting beds in his backyard, the subject of mulching has arisen. Now, my own personal preference is to not mulch at all but I also recognize that not everyone has the time available for the Eternal Vigilance of weed control (he doesn’t)….nor the inclination toward a compost bin to provide an ongoing supply of top-dressing (neither he nor I do.) So, faced with a mixed border of about 25% trees/shrubs and 75% perennials, what’s a time-challenged gardener to do?

It’s certainly not as if I haven’t gone down the mulching road in the past. In my first garden my mulch of choice was cocoa bean hulls which was the New Mulch on the Block at that time (1970s). From a tactile standpoint this is absolutely lovely stuff to handle, and of course it smells slightly like chocolate for a while although not from any distance. It’s lightweight and a joy to spread around, and is totally unobtrusive. That garden was waterfront and I was worried about it blowing away but once initially wetted down it actually does stay put.
Drawbacks: It’s not that easy to find, and prices for a 2-cu.ft bag vary widely. It’s not likely that you can find it sold in bulk like many other mulches.  It’s perhaps not the ideal choice for a sloped bed because heavy downpours can result in washdown; I found that out the first summer. If your garden has humid summers, the mulch can develop areas of a whitish mold that is supposedly harmless but not very pretty. And most important, if dogs have access to your garden you don’t want to use this mulch because the same theobromine that is in chocolate is also in the hulls, so if for some reason a dog decides to eat the mulch it will probably become sick to its stomach just as if it had eaten chocolate candy; however, there appears to be only one documented case of a dog actually dying as a result of having eaten cocoa mulch.

At my second garden I had the not-so-bright idea of using some of a neighbor’s free-for-the-taking fresh wood chips from their tree removal. The unfortunate result is related in this post!

After that nasty experience I embarked on a “mulchless forever” course and instead relied on perennial groundcover plants such as vinca, hardy geraniums, epimediums, liriope, and of course the much-maligned but undoubtedly useful pachysandra although I wouldn’t put that into a mixed bed. Empty spaces were hand-weeded.

 

I kept up that philosophy at my third garden except for a couple of smaller beds into which I put Sweet Peet®. I do think that as mulches go this is one of the best. It’s actually a mixture of peat and composted animal bedding. It’s attractive (assuming that you don’t like artificial colors or big chunks of anything), neat, and effective.
Drawbacks: The top three drawbacks to Sweet Peet are cost, cost, and cost. This is probably the most expensive mulch you can buy – other than river rocks, etc. – at an average price of $9 per bag, and they are 1.5-cu.ft bags rather than the typical 2-cu.ft. so you need more bags to cover the same area. Buying by the cubic yard is less expensive but still not cheap. Because of its composition it will break down faster than something like bark nuggets or wood chips. However, if you’re using it in the initial planting stages and the plan is that the gaps will be filled in by plants within the next 3 years, this is a great choice if the budget allows.

However, here at the Temporary Garden/Money Pit, although I theoretically have the time, my various herniated discs don’t take kindly to endless hours of weeding. That’s what prompted the Mulch Madness of 2015, in which two types of mulch were experimented with: triple shredded bark and shredded cedar.

The triple shredded hardwood bark looks like this. I have to confess that for some reason I really do not like this mulch. Maybe it’s because in my opinion mulch should look like something other than exactly like dirt with a lot of “stuff” in it. Color-wise it’s pretty darn close to black, something else I was not expecting and do not like. Does it do the job of suppressing weeds? Yes, except for the ones that germinate on top of it (Sweet Peet doesn’t seem to have this problem as often, in my experience anyway.) I’d never used this before, or even seen it, so it was one of those learning-experience, won’t-do-that-again moments.
Drawbacks: Critters such as squirrels love to dig holes in this stuff because, well, it’s so easy for them to do. Also, it is probably the most expensive of the wood mulches, hereabouts.
Update: This later turned out to be the Mulch From Hell, and I would never recommend it to anyone; see why, here.

 

I couldn’t afford to put the triple shredded on more than 1/3 of the planting areas here, which meant there were still a lot of potential weed-farms left. For half of the remainder I chose cedar bark mulch. It definitely looks like mulch, not dirt, and it smells lovely when putting it down and for a short time thereafter. I chose cedar rather than the cheaper pine bark because I really don’t want to have to reapply it (hoping to have moved before that’s needed!) and cedar takes longer to break down. However, it also lightens in color over time, eventually becoming a kind of silvery/greige rather than tan. But it’s doing as good or better a job of weed suppression as the more expensive triple shredded stuff. And it stays in place; no worries about high winds, torrential downpours, etc. And so far, critters don’t seem to like to dig in it.
Drawbacks: It’s more of a nuisance to put down in a perennial bed because the “pieces” are larger; you don’t want to smother things, especially if you’re growing things like peonies (or bearded iris which shouldn’t be mulched with anything at all). For a tree or shrub planting, I would definitely go with cedar if I wasn’t using groundcover plants instead, or as a temporary filler between newly planted ones.

 

One thing I have used around clematis is pine bark mini nuggets, until the surrounding plants get wide enough to shade the clematis roots. By the time the nuggets break down, the other plants are doing their job. The nuggets shade the clematis roots but also have enough spaces between the nuggets for a free flow of air and water. There’s probably no scientific basis for using them in this particular way but it has worked for me and so I don’t plan to mess with success!

IMPORTANT UPDATE: Before deciding on using any wood-based mulch within 30 feet of a house or where a vehicle is regularly parked, please read my December 2017 post about the Phantom Mulch Menace!! I learned this lesson the hard way. But if your area to be mulched doesn’t fall into either if those categories, you are safe with wood mulches.

In case anyone is wondering why I haven’t mentioned pine needles as a mulch, it’s because that material is almost unknown commercially here in the Northeast. In more than four decades of gardening here I’ve never once seen it offered for sale either in bags or in bulk.

To be honest, for a planting in which I did not ever anticipate adding, dividing or moving things – say for instance an all-shrub or just shrub/tree bed – I’d probably choose either a natural undyed pebble, river stone, or crushed stone mulch if I wasn’t going entirely mulch-free. Certainly the only thing I’d put next to a house foundation from now on would be a stone mulch; if there’s one thing I’ve learned to my cost here at the Money Pit, it’s that house foundations should be kept totally clear of either plants or organic mulches for at least 24″ outward. Many problems can be avoided that way, and it’s also easy to notice and quickly repair things like cracks and gaps if you have a clear view of the foundation all around.
Drawbacks: Stone mulches need deep pockets and strong backs. Depending on the color, it can absorb a lot of heat and transfer it to the soil (thus drying it out) which can be good or bad depending what you’re growing and where. If, like me, you hate dyed mulches there’s pretty much no way that a stone option is going to be unobtrusive or “look like dirt”: it’ll be some shade of white, tans, bluish grey, or reddish. And if you’re going to ever need to kneel on the stuff, better stack at least two of those kneeling pad things before you get “down and dirty” because otherwise your knees will not be happy!

A somewhat lighter weight option is Timberlite which is a volcanic (igneous) rock. Although not as heavy as standard rock mulches, it’s definitely heavier than any of the organic options. Timberlite is sometimes sold under the trade name of Sunrise. One online source claims the rock is called “anthrobrite” but I haven’t found any confirmation of that in any geology reference sites. The red, black and brownish colors of Timberlite are natural; it is not dyed. Perhaps it is a blend of various igneous rocks such as rhyolite, scoria and basalt?
Downsides: The individual irregularly-shaped Timberlite rocks average about 1″ in diameter; there is no “smaller size” version and therefore its’ really not suited for most perennial beds. I used this as a pathway surface at my last house and although I liked its appearance it is neither comfortable nor easy to walk on, because of the non-uniform surface; I always felt as if I was one step away from accidentally turning my ankle. It’s definitely worse to kneel on (even with pads) than river rocks or pebbles.

So if a mulch is to be used in my son’s new plantings, I will probably recommend a mixture of two different kinds. The first (largest) bed is backed by a row of huge conifers, has two skinny oaks, and will have a group of shrubs (pieris and fothergilla) added in the center. Eventually vinca will fill in that area but in the meantime my gut feeling is to go for the bark nuggets or larger shreds. The front of the bed will be all perennials and bulbs and so that will be trickier. If ’twere me, I’d probably bite the budget bullet and go for the Sweet Peet while crossing fingers that everything will fill in sufficiently so that I wouldn’t need to do it a second time. But faced with fiscal practicalities I’d opt for Grade A cedar (assuming the lighter color isn’t a problem) or two types of pine bark mulch: nuggets near the trees and shrubs, and the more common shredded variety in the perennials section…. being careful to keep any mulch away from all trunks and crowns, of course! 🙂