What Is Living Mulch?
Living mulch is a type of organic soil amendment that consists of shredded leaves, grass clippings or other organic matter such as wood chips. The term “mulching” refers to the practice of adding material (usually leaves) to improve drainage and hold moisture in the soil surface.
The main benefit of using living mulches is improved drainage because they trap water droplets when it rains or snows. They also act like a sponge holding excess moisture in the soil.
Mulches are often used in gardens where there is little space between plants and no room for natural drainage systems. These types of garden beds may include trees, shrubs, flowers and perennials.
Plants that require constant watering such as vegetables or fruit trees will benefit from having a mulched area around them.
Types Of Living Mulches
There are two main types of living mulches: perennial and annual. Perennial living mulches are added year after year while annuals last only one growing season.
Both types have their advantages and disadvantages. Let’s take a look at each type and its benefits and drawbacks.
Perennial Living Muds
These mixtures consist of shredded leaves, grass clippings or other organic matter such as wood chips. The shredded material is broken down in size from large to small.
The larger pieces allow for air flow while the smaller pieces allow moisture to reach the roots. The most common types of living mulches include gravel, hay, pine needles, cedar and hemlock.
The most popular living mulch used is shredded hardwood leaves, which are usually available free of charge. It is very easy to apply and will help soil conditions by improving its structure.
Be sure to layer the leaves or grass clippings 2 to 4 inches deep. If you are using this type of living mulch, be aware that it may carry harmful diseases or insects that could damage your plants.
The next most popular is pine needles. There is some debate concerning the use of this type of mulch.
Many experts claim that it prevents the plants from absorbing certain nutrients such as nitrogen while others believe it acts like an acid and actually releases nutrients for the plants. Most gardeners have observed neither effect and claim that it is just a natural organic mulch that looks good.
Another type of living mulch is cedar mulch. It does not break down easily, looks good in the garden and has a nice smell.
Be careful with this type of mulch because it may contain harmful chemicals that could be released when it comes in contact with the soil. If you are using this type, layer it at least 3 inches deep and away from the base of the plant’s stems.
Heathmulch is another type of living mulch that is similar to cedar. It has many of the same positive attributes as cedar with one exception: it is not dyed bright orange.
Living mulches are very easy and inexpensive to use. They can be top dressed as the plants grow and require very little maintenance.
They do have one drawback: they do not control weeds as well as some other mulches. Weeds must be pulled or tilled under to prevent them from going to seed and re-appearing the next season.
Annual Living Muds
These types of living mulches are very easy to apply because they are seeds that you simply scatter over the area you wish to cover. They will germinate and grow into a lush green cover that will eventually die and break down during the winter months.
Annual mixtures usually consist of a mixture of rye, oats, and buckwheat. These plants germinate quickly, suppress weeds, add organic matter to the soil and release nitrogen.
The problem with most of these living mixtures is that they are annuals and will have to replaced every year. If you live in an area that has a mild winter (not freezing), these mulches can be sown in the fall and will germinate in the spring.
Annual bluegrass, ripgut grass and some clovers are also used as living mulches.
The same drawbacks apply to these types of living mulches: they will have to be replaced every year so you need to find a place to store the seeds over the winter; they may come with their own share of weeds and they may not suppress other types of weeds that are already in the area.
When purchasing any living mulch, be sure to get one that is suited to your particular needs and one that you can obtain locally. It would be a real pain to have to order your mulch from somewhere else and have it shipped in.
More than likely, you will have forgotten what the exact types of seeds were by the time they are to be planted next year!
Inorganic mulches are not organic. They will not rot down and add to the soil and they may even affect the chemical nature of the soil.
This type of mulch consists of several different materials such as gravel, sand, stone, rubber, metal and plastics.
Gravel and sand are often used around the base of a plant to keep weeds from growing and to keep the root system cool. The problem with gravel and sand is they can keep water from draining into the soil profile.
Concrete and brick pieces can also be used as mulch in a landscape. They keep weeds from growing but cannot be kept permanently around a plant’s root system because they will cause the soil to dry out quickly.
Wood mulches can be used around shallow rooted plants such as flowers and shrubs. Cedar is often used, but is rather expensive.
Other types of wood can be used but they may attract insects or rodents. Wood mulches keep weeds from growing but they will also dry out the soil. They also need to be replaced every once in a while because they tend to decompose and break down.
Pine needles are often used in a landscape. They are less expensive than wood mulches and they tend to help the soil around them stay moist longer.
The only problem with pine needles is that they can make it rather difficult for some plants to grow. Pines also have a habit of blowing around in the wind and spreading their seeds.
Straw and hay are also often used as mulches in a landscape. They are a little heavier than pine needles, but not as heavy as wood and will not decay as quickly as wood does.
They are often inexpensive and can be purchased locally from a farmer.
Newspaper is an unusual mulch used by gardeners. It is lightweight, breaks down quickly and is not very expensive.
It works well around plants with shallow roots because it helps to retain the moisture in the soil. It comes in large sheets so it can also be used to prevent weeds from growing as well.
Rubber mulch is made from recycled tires. It is not very expensive and can be found at many nurseries.
It helps to prevent weeds from growing because nothing can get through it, unless you also put fertilizer in with the rubber mulch. If you do this, you will have to water the plants more often because it prevents the moisture from soaking into the soil.
Fiberglass bark is often used around trees and shrubs. It is not very expensive and can be found almost anywhere.
It does prevent weeds from growing, but it can also dry out the soil around the plant because it does not allow water to soak into the soil.
Weed barrier is not a mulch but it can be used in place of one. It prevents weeds from growing and keeps the soil around plants moist for a longer period of time.
However, it is rather expensive and hard to find at most nurseries. It can be placed over the soil and then covered with mulch.
Inorganic mulches are not recommended around trees and shrubs because they do not allow moisture to soak into the soil properly. You may need to water these types of plants more often than those that have mulch around them.
Maintaining mulched plants
As I stated above, many mulches will need to be replaced every once in awhile. This is especially true if you use mulch like gravel, wood chips, or crushed stone.
You will also need to replace these types of mulches more often if you live in a place where there is a high concentration of limestone in the soil. These mulches tend to break down quickly under these conditions.
Many types of mulches, such as wood mulch, pine needles, and straw will need to be raked loose around the base of plants. This prevents the plant’s feeder roots from being covered.
If these become covered, the plant will not be able to get the moisture and nutrients it needs and it can die.
Synthetic and organic mulches can also be applied too thick. This can prevent moisture and nutrients from evaporating into the atmosphere.
A good rule of thumb is to apply a two to three inch layer of mulch around your plants. If you are using wood chips, you will need to replace them more often because they tend to break down more quickly.
Mulches can also hold onto moisture, which is great during droughts. The problem is they can also hold onto the water during heavy rains.
If too much water is held by the mulch, it can cause the plants to float out of the ground and be damaged from the excess water or the mulch could wash away altogether. If you live in an area that has heavy rains, it might be a good idea to remove mulch from around plants during these times.
Organic mulches such as manure, grass clippings, leaves and hay will usually need to be replaced once a year. They also need to be mixed in with the soil each season.
This is because over time they break down and provide less of the nutrients that plants need.
Using mulch around your plants can be very beneficial if done properly. It can save you a lot of time and energy that you would have spent cleaning up around your plants.
It also can prevent weeds from growing as well as keep the soil around your plants at the right moisture level. Happy gardening!
More information on mulches
Types of mulches – There are many types of mulches from which you can choose. Each has its own benefits and drawbacks.
Mulching – Everything you need to know about mulching!
Plant Diseases – Learn how to identify, treat and prevent plant diseases.
Soil – The key to growing healthy plants!
Watering – When and how to water your plants
Planting – Get tips on proper planting techniques
Pests – Identify and get rid of those pesky pests!
Weed Control – Stop Weeds in their tracks!
Composting – How to make you own free fertilizer!
Greenhouses – How to construct your own for maximum growing potential
C Flag – How to plant a C-Flagpole in your garden, for patriotism and more growing space!
Gift Giving – Garden gifts for that special someone!
Sources & references used in this article:
The historical roots of living mulch and related practices by LK Paine, H Harrison – HortTechnology, 1993 – journals.ashs.org
Managing white clover living mulch for sweet corn production with partial rototilling by VP Grubinger, PL Minotti – American Journal of Alternative Agriculture, 1990 – JSTOR
Earthworm community in conventional, organic and direct seeding with living mulch cropping systems by C Pelosi, M Bertrand, J Roger-Estrade – Agronomy for Sustainable …, 2009 – Springer
Subterranean clover living mulch: an alternative method of weed control by RD Ilnicki, AJ Enache – Agriculture, Ecosystems & Environment, 1992 – Elsevier
Establishment of asparagus with living mulch by L Paine, H Harrison… – Journal of production …, 1995 – Wiley Online Library
Reseeding of crimson clover and corn grain yield in a living mulch system by JDT Kumwenda, DE Radcliffe… – Soil Science Society …, 1993 – Wiley Online Library