Dark Hemlock in the foreground, Cedar Chips make up the path in the background.
Mulch? What is it, what is used for and more.
Mulch is a layer of material applied to the surface of the soil. So that definition is pretty encompassing, and it kind of needs to be. Mulch can range from wood products, to stone and even shredded tires. But for the sake of this post I am going to concentrate on wood mulch.
I should note that I am writing this here in Portland, Oregon, so the types of materials that are available to me, may be different than what is available to you. That said the concept surrounding wood mulches is relatively universal.
Wood Mulch has a number of positive attributes.
First and foremost it improves the aesthetic of your yard and gardens. A freshly weeded and primped garden with a new layer of mulch makes you look like a home owning rock star and makes your neighbors envious. Plain and simple, it looks good.
Freshly spread Dark Hemlock mulch allowing this Ceasars Brother Japanese Iris to shine in contrast.
But when you get below the surface of the beauty, quite literally, there is much more going on with your wood mulch.
It acts as an insulator. In the summer a 2-3” layer of wood mulch will keep your garden soil temperature cooler. Conversely in the winter it will help keep your soil warmer. Which is important to your plants.
Wood mulch also helps shade your soil and slows evaporation of the moisture just below the surface. In the summer sun this is important as it helps keep your plants hydrated and conserve the water you had given your thirsty plants.
Because wood mulch is organic it breaks down, in doing so it adds nutrients to the soil. Now that doesn’t mean adding compost to your soil from time to time is unnecessary (see postscript below). But I would characterize organic material being worked into your soil as an added value.
Last but not least, and likely most important to most people, it helps prevent weeds. By shading the soil as was mentioned above it can prevent weed seeds from germinating and taking root in your gardens. Before you get too excited, this mulch is not miraculous. You’re going to get weeds and the best way to deal with weeds is to pull them, root and all. But mulch will help your cause.
Now as long as we are talking about weeds there is something you need to know. DO NOT use weed fabric with wood mulch. If you are using decorative stone in your landscape, then a layer of weed fabric is a must, but not with mulch. Even though I wrote in capital letters, DO NOT, and my mother would tell me that writing with capital letters is rude because it implies that one is shouting, someone out there reading this will do it anyways. If you scroll down to the postscript I will blather on about why this is a no-no.
Example of using weed fabric beneath the gravel (1/4" minus #10) but not under the Dark Hemlock
No mulch is created equal. There are a number of different types of wood mulch and they can be used for different scenarios.
Medium Dark Hemlock Mulch
Medium Dark Hemlock: Admittedly this is my favorite and the one I use most often. I like this mulch because it is relatively durable, it has a nice dark chocolate color and it will not give you slivers. It can be applied 2-4” thick.
Fresh Fir Mulch
Fresh Fir: Another option that is slightly more economical is Fresh Fir. The color is slightly similar to the Hemlock, a bit lighter, maybe not as durable. This one however can be prone to slivers, making gardening a little painful.
Cedar Chips: If you have an area where there is dog traffic or you want to create a walking path or even mulch a children’s play area then Cedar Chips are a great option. There are a few things to consider if Cedar Chips are a mulch option you are weighing.
Cedar Chips tend to be quite durable, thus a good choice for area where dog traffic is heavy, paths, and kids. I haven’t found them to give slivers, so that’s a plus. The chips tend to not cover as much area as the hemlock or fir options and the chips also don’t bond together like the others will. When applying these I tend to spread them a bit thicker, 3-4” deep.
Example of using Cedar Chips for a path, dark hemlock on the sides of the path
Personally I don’t like using cedar chips for planting beds. They are initially very bright and blond in color before later graying. It is my opinion that they look unnatural and do not contrast well with plants.
Hog Fuel: The last option to consider is called Hog Fuel. Sounds sexy right? How this mulch earned this name is in question, but likely derived from the machine that processes the wood waste into mulch. Anyhow, Hog Fuel is a rough cut of mulch. It can come from different types of wood so it may have a different look from one supplier to the other. It is an economical mulch option that can be good for walking paths, and covering areas not in plain view.
A few last thoughts on mulch. And if you have read this far, you are probably wondering how one can have so many thoughts on mulch. I’m a gardener, what can I can I say?
The urge is to mulch early in spring when things are beginning to come to life. One tip is to wait just a bit. The rain and moisture break down mulch, spreading your mulch in mid to late spring will help it last a bit longer. And last, if you have a new garden, you’ll likely be mulching it. So the following year you should mulch your gardens again. After that you should have a good base of mulch in your gardens. Now mulching every other year should be sufficient. With that, happy mulching!
Compost + Mulch=Happy Plants
If you have planting beds of perennials, shrubs and trees it is always a good idea to over time add compost to your soil. Compost and mulch are different things. Compost is decomposing plant material; mulch (wood mulch) is waste material from the processing of wood. Compost is full of nutrients that will help nourish the soil and make your plants happy. The proper order of operations can be to add a layer 2-3” thick of compost to your gardens. Then add a layer of mulch, options discussed above.
Much + Weed Fabric=NO
When you spread wood mulch atop weed fabric you are setting yourself up for the trials and tribulations of immediate gratification, and long-term displeasure. In the short term (6 months to a year) everything will look great. In the long term (1 year to the time between when you grumble about your misdoings until the time you re-do the project) it will become a hard to maintain mess.
As I noted previously wood mulch breaks down over time. So essentially it breaks down into soil. When this happens you have soil on top of the fabric, which is on top of the soil. A soil-fabric sandwich. Weed seeds just blowin’ around or seeds eaten and digested by a bird that drops a present in your yard now have a fertile space to take up residence. The weeds put down roots in the soil atop the fabric. But as they establish their bad self those roots spread and bond to the fabric, their roots will continue to grow and wiggle between the tiny spaces in the fabric to the soil below. When this happens the weeds become very difficult to remove.
If you need gardening and mulching services in North and Northeast Portland Oregon, Contact Wheel & Barrow Landscape Design and Maintenance.