The Casual Gardener: Much ado about mulching
Mulches come in many forms and serve a number of purposes but their primary purpose is to lock in moisture
IF YOU'VE been off road in recent weeks, you'll no doubt have noticed how sodden everywhere is. The snow at the beginning of the month fell on to ground that was already saturated, so when it melted there was nowhere for all that moisture to be absorbed, meaning much of it now lies on the surface.
In moderation rain is good for the garden, as it is water which enables plants to take in nutrients from the soil through their roots. However, they tend not to need much moisture during the dormant season when they're not actively growing.
Ideally, the gardener wants to be able to store the water that falls in greater quantities over the winter months and stockpile it for the summer. You can do this using a water butt. However, realistically there are limits to how much water you can harvest in a butt or two.
This is where mulching comes into play. It may sound complicated, but mulching is a very simple but effective way of keeping your ground moist during the drier months.
A mulch in its broadest sense is any layer of material that covers ground, whether cultivated or not. Working as a barrier that slows the dehydration of the soil during the warmer months, the mulch traps the moisture below.
Mulch materials can be organic or non-organic; permeable or impermeable; strictly functional or aesthetically pleasing – or both. Mulches I've used in my own garden with varying degrees of success include cardboard, carpet, polythene, grass cuttings, bark chips and stones/gravel.
What you need the mulch to do will dictate what it's made from. For instance, a leaf-mould mulch is great for beds and borders in late spring, while at the opposite end of the scale you could have a permanent mulch of recycled glass pebbles for an ultra modern space.
The latter type of mulch is deployed where a low-maintenance solution is required, and is essentially a permeable membrane covered with the topping of your choice. In my experience this will work as a weed suppressant but if organic matter accumulates – dead leaves etc – weeds will grow on top.
This approach ticks many other boxes, but it can be a bit lifeless and dull – what many may regard as the antithesis of an attractive, living garden.
The appearance of the mulch will therefore be greatly enhanced if punctuated by planting, whether alpines, herbaceous perennials or shrubs.
Biodegradeable organic mulches are designed to break down gradually, releasing nutrients into the soil and helping improve its structure. This method also acts to suppress weeds, retain moisture in the soil and make your beds and borders more presentable.
Among the best materials are leaf mould, garden compost, spent mushroom compost and well-rotted manure. This sort of mulch is best applied from mid to late spring and autumn, when the soil is moist and warm.
To be effective, biodegradable mulches need to be between at least 5cm thick.
Beds and borders can be mulched entirely, taking care not to smother low-growing plants or to pile mulches up against the stems of woody plants. If the mulch material comes into direct contact with the stems of trees or specimen shrubs they can cause the stem to soften, making it vulnerable to attacks from pests and diseases.
There's also the possibility that by applying a poor quality mulch full of seeds and grass roots that you'll merely introduce weeds – and diseases such as honey fungus too – that wouldn't have otherwise been there.