Mulching is an excellent way to ensure that plants in landscaped areas stay healthy. We can use a wide range of materials, some of which are drawn directly from nature. All we have to do is cover the surface of the soil with mulch, sit back, and reap the benefits.
The choice of which mulch to use will depend primarily on what is available to you. Two of the most popular mulches are wood mulch and leaf mulch, and both are readily available in most places. Both are organic, and both have pros and cons. This guide will help you make an informed choice.
What is leaf mulch?
Leaf mulch is created from fallen leaves that are commonly coarsely shredded. Whole dry leaves tend to blow away and if you shred the leaves too finely, the water won’t penetrate the soil fully.
Leaves are usually very easy to get hold of and they make an attractive-looking mulch. They decompose naturally and you can eventually dig the mulch into the soil before replacing the mulch.
Beech and oak leaves are a good option in any landscape where acid-loving plants are growing. So, too, are pine needles, though these have other cons.
Another option is leaf mold, which consists of leaves that have started to decompose. It adds quality to the soil and, if already well decomposed, can be used as an amendment rather than a mulch on the surface.
What is wood mulch?
There are different types of wood mulch including pine bark, shredded hardwood, hardwood bark mulch, and wood chip mulch. They all make an attractive mulch wood cover.
All types of wood mulch are good for weed control.
Shredded hardwood decomposes quite slowly and it doesn’t wash away easily. It is available in fine and coarse textures.
Pine bark is usually a dark color and is available in different forms and sizes, from shredded bark mulch to larger nuggets. Nuggets will float and may wash away in heavy rain.
Wood chips mulch is sold in various sizes too. The smaller the wood chips are, the more quickly the mulch will decompose.
One caveat is that hardwood mulch, in general, tends to be alkaline. So, as it decomposes, it will make the pH of your soil more alkaline.
What does leaf and wood mulch do?
Leaf mulch and wood mulch have many beneficial effects on the soil and plants. But, as the Clemson Cooperative Extension points out, the mulch must be applied correctly.
We use leaves, wood, and other types of mulch to help retain moisture around the root ball of young plants until the roots are established. It smothers weeds and is invaluable for helping prevent damage to plants, including tree trunks, by trimmers and lawn mowers.
It also regulates soil temperatures. And, as it starts to decay, the mulch adds beneficial humus to the soil.
How to lay mulch
It’s a good idea to weed the area where you are going to lay mulch. Then spread it over the whole plant bed.
There are a couple of golden rules. One is to avoid piling mulch up against the trunks of trees.
It’s best to keep all types of mulch including wood, leaf, and hardwood bark mulch 2-3 inches away from the stems of any woody plants. This will prevent the wet mulch from causing decay during winter.
When you plant trees, a good rule of thumb is to create a circle of mulch that is 3-4 feet in diameter. For established trees, you’ll need the circle to be about 2 feet in diameter for each inch of the trunk diameter.
When wood, bark, and chip mulch have fine particles, don’t lay it more than 2-3 inches deep. Too much fine-textured mulch can suffocate the roots and affect growth.
Coarse mulches like bark nuggets allow air to circulate and so the mulch layer can be up to 4 inches deep.
When you use shredded leaves and/or grass clippings the mulch shouldn’t be any deeper than 2 inches. These materials have a tendency to mat and when this happens water and air supply to plant roots is restricted.
The plant scientists from the University of Connecticut Home and Garden Education Center warn that if the mulch is too thick, water won’t penetrate the soil.
They advise that you thoroughly water new bark or wood mulches. They also say it’s a good idea to add nitrogen to garden soils before you apply a wood mulch of any sort, including wood chips.
The problem here is that wood-derived mulches absorb nitrogen. Dig a little urea, blood meal, or a high-nitrogen lawn fertilizer into the soil before you lay the mulch.
Benefits of leaf and wood mulch
Both leaf and wood mulch are organic and they can help to improve the structure of the soil. As these mulches decay, the organic matter adds soil nutrients and improves the topsoil.
It encourages the activity of beneficial soil organisms too.
Mulch maintains a reasonably even soil temperature by keeping the soil warmer in winter and cooler in summer. For example, tests show that wood chips will keep the soil as much as 30 ℉ cooler than bare soil that hasn’t been mulched.
Mulches also prevent excessive evaporation from the soil.
As long as the mulch wood chips and/or leaves are free of weeds and are applied deep enough, they will prevent weeds from germinating. But they encourage the growth of the plant roots.
Leaf and wood chip mulch prevents water from splashing up from the soil. This stops soil erosion and also protects the plants from soil-borne diseases.
In the same way, the mulch prevents the soil surface from crusting as well as soil compaction. This improves water absorption into the soil.
When to apply mulch
Lay your mulch around established plants in spring. If you’re planting new flowers, bushes, trees, and shrubs, mulch straight away before weeds gets a chance to germinate.
When the mulch decomposes, replenish the mulch. This will depend entirely on the mulch that you have used.
Leaf Mulch Vs Wood Mulch: Pros and Cons
Both leaf mulch and wood mulch have pros and cons. Let’s take a look.
Chopped or shredded leaves don’t blow around very easily and they make an attractive mulch.
Leaf mulch contains valuable plant nutrients and provides good winter insulation against wind and cold. It tends to retain water providing constant moisture.
The nutrients in leaf mulch attract earthworms and other good organisms.
Dry leaves are likely to blow around in windy weather. Leaf mulch also decomposes rapidly.
If you use pine needles as leaf mulch you will find that they form a more impenetrable barrier above the soil. This is great for weed control but it can stop water from getting to the soil.
Wood chips sometimes contain wood waste products. This is okay, as long as the materials are tested and certified to be free from preservatives and other contaminants.
Also, shredded hardwood bark needs to be replaced more often than shredded softwood bark.
Wood mulch controls weeds well and it’s decorative. Shredded bark will keep the soil moist and cool, and it’s readily available. It is also super-easy to rake.
Hardwood mulch is long-lasting and is often available in different colors. If this takes your fancy, it’s a pro!
When the weather is very wet, shredded bark can sour and become toxic. This usually happens when the mulch has been piled high during storage and the inside of the pile is deprived of oxygen.
When wood chips have a high carbon content, they can cause a temporary nitrogen deficiency in the soil.
What type of mulch looks best?
Mulch can improve the aesthetics of any landscape by providing a cover that has an interesting texture and more or less uniform color.
Apart from organic mulches like leaves and wood chips, inorganic mulches may also be used. These include pebbles, gravel, and various manufactured landscape fabrics.
They all have a different appearance and personal choice will determine your choice.
You might also want to choose a mulch that complements your garden beds. Although leaf and wood mulch colors are all-natural greens and browns, some are darker than others.
Different types of mulch can help you cut back on garden maintenance. They cut back on weed growth and the best mulch will provide soil nutrients as well.
Leaf mulch and wood mulch are both popular types, and equally easy to find. Most people buy wood mulch, while you can gather fallen leaves at no cost if you are willing, able, and have a source.
It is true that wood chips and other wood-derived mulch last longer than leaf mulches. But leaf mulch and leaf mold will decompose into organic matter which is, in itself, an advantage.
Wood mulch is often alkaline, while some types of leaf mulch are acidic. Wood mulch is also heavier than leaf mulch, although this could be an advantage in windy areas.