(Originally posted: July 11, 2019)
As promised, I am following up my previous post about edging with a post about mulching- it is the ultimate finishing touch that helps make a garden look fabulous. There is a LOT to say about this topic, so I am dividing it into two parts: a mulch primer, followed by tips for doing a top notch mulching job.
OK. Let’s start with a little discussion about mulch shall we?
Aside from really setting off the plants in your garden and giving the garden beds a nice uniform look, the value of mulch goes well beyond aesthetics. It has some really important environmental benefits too. Here is a brief low down:
Benefit #1:
A layer of mulch acts as a sort of semi-permeable barrier when it comes to water. It allows rain/irrigation water to seep through to the soil but it also helps to slow down water lost from the soil due to evaporation- delaying the need to add supplemental water during dry periods… thus conserving this precious resource! (This ability to conserve soil moisture is also why we don’t want to apply mulch to water-logged spring soils… for the health of our plants, we want to encourage these soils to dry out a little before ‘locking in the moisture’!)
As summer weather hits, our minds shift to water conservation. In a garden, mulch is an important piece of the ‘water conservation puzzle’.
Benefit #2:
A layer of mulch can absorb the impact of driving rains thus preventing your garden soil from washing away or splashing up on your plants- a relevant concern given the weather we have been experiencing as of late! Mulch fibres tend to weave together which helps the layer stay in place in conditions that would otherwise wash soil away. (It is important to keep in mind that when mulch fibres become too interwoven, the layer has a tendency to repel water- this is where ‘fluffing’ the mulch every now and then is a good idea.)
Benefit #3: Exposed soil just screams “Hey weeds! Land available- make your home here!” The barrier provided by mulch can help control weeds in two ways. First of all, a good mulch layer (around a 3” depth) can prevent existing weed seeds in the soil from taking hold by eliminating the sunlight required for them to germinate. The layer of mulch is also not conducive to rooting, so seeds blowing into the area will have little success at ‘laying claim’ to the land. With that said, it is important to weed your garden before applying mulch. You may think you have won the war by covering up your unwanted plants, but most likely you have not. Sorry. Existing weeds will often grow right through the mulch… forcing you to actually deal with the problem instead of covering it up!
Attack of the weeds! Mulch can be used as a weapon in the war against weeds in your garden.
Benefit #4: Mulch is a natural product that, when it breaks down, it adds organic matter to the soil (which in turn adds nutrients to the soil, increases the water holding capacity of the soil as well as the ability of the soil to retain nutrients). Organic matter can also help break up clay soils and ‘beef-up’ really sandy soils (in general, it improves the structure of the soil). In this way, mulch is another way we can ‘give back’ to our gardens during the growing season!
Benefit #5: Mulch can help moderate soil temperatures, buffering plants from the heat of summer and the cold temperatures of winter. This can be the difference between the survival or demise of more tender plants (or plants growing at the edge of their climatic limits).
Clematis is a plant that benefits from a generous layer of mulch to moderate soil temperatures.
Types of Mulch and How Much to Use
Organic mulches are really the only type of mulch to consider for a garden. Of the organic mulches, the most readily available ones for the home gardener are the shredded bark mulches that are found in bags at your local garden centre. Usually it becomes a choice between pine and cedar. There is also a choice in colour as dyed mulches are available in brown, black or red (gag!).
Bagged shredded cedar mulch. Note the shredded/fibrous texture of this mulch.
So how does one choose? Here are some points to consider when choosing a mulch for your garden:
Pine mulch tends to be lighter in colour and breaks down faster than cedar mulch (this is not necessarily a bad thing since you will need to reapply mulch on a yearly basis anyway; I personally like a mulch to break down quickly so that it is incorporated into the soil sooner.)
Pine is more acidic than cedar
Cedar mulch tends to have a naturally reddish colour to it
The stained mulches may look nice when first applied but they tend to fade (in full sun situations they can start looking very ‘tired’ quite quickly)
Black mulch shows every single piece of debris that lands on it
Red mulch is just wrong and shouldn’t even be considered an option! (This is the hideous orange-red mulch that tends to be used in parking lot and gas station gardens. If you love your garden and want to show it off, I am begging you…DON’T USE THIS MULCH!)
Some other variations are available when buying mulch in bulk. If you are happy to get a pile of mulch dumped on your driveway, this is certainly the most economical way to go! I personally like a composted pine bark mulch. It has a more uniform consistency than the shredded mulches and it doesn’t tend to weave together. This does make it more susceptible to swimming away in driving rains… but considering the downpours we have seen in recent years, I have found it to hold up extremely well!
Composted pine bark mulch. Note the more consistent texture of the mulch particles compared to the shredded bark mulch. This mulch lacks the fibrous quality of the shredded bark mulches and the particles do not weave together.
I realize there are even more options when it comes to mulching (straw, compost, shredded leaves, wood chips to name a few) but I will save these for future posts. Let’s get on with the task at hand… applying mulch to our gardens! (Which just happens to be covered in the next post…)
