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What is Mulch?

Posted on by Urban Eden

There are certain terms in the landscaping business that may stir up a bit of confusion, especially for those unfamiliar with the professional trade. Mulch seems to be one of those terms. This post will explain what mulch actually is and what forms it comes in.

So, What’s Mulch?

In essence, mulch is any cover material that is spread over the soil’s surface. Mulching has several benefits; it’s used for inhibiting the growth and spread of weeds, insulating the soil against extreme temperatures (both heat and cold), moisture retention in the soil, and to add an attractive appeal around your landscape.

There are two main categories that mulch is divided into, organic and synthetic. There are pros and cons to each category, and the type you use will depend upon your needs.

Organic Mulch

Organic mulch comes in many different forms. However, all organic mulch decomposes over time. The decomposition process means that it will, eventually, need to be replaced or rejuvenated with fresh mulch. However, as the organic mulch decomposes, it helps to build better soil by adding beneficial nutrients.


Bark mulch comes in a plethora of varieties. Hemlock, pine, and cedar are some of the most popular varieties available. Bark mulch also comes in different forms as well. The bark can be in the form of “nuggets,” “chips,” or a finer “dust.” The variety and form you use will depend upon your preference. Bark mulch is generally used around trees, shrubs, and bushes, as well as in garden beds that do not see a lot of continual digging.

Grass Clippings

Clippings from your lawn can be used as a mulch as well. Grass mulch has a tendency to retain a lot of moisture, but breaks down rapidly and will have to be replenished often. The most popular place to use grass clippings as mulch is directly in the lawn itself. When mowing, instead of bagging the grass clippings, use the mower’s mulching feature to cut the grass and leave it in the lawn. As the clippings break down, they add fertility to the soil, improving the health of your lawn. Other popular uses for grass clipping is to build up a compost pile or to use the clipping directly on unplanted areas.


Leaves, albeit, perhaps, not the most attractive mulch, works quite well. Depending on your property location, leaves are abundant, and, perhaps most importantly, free. Shredding the leaves will offer the best results, but whole leaves can accomplish similar results.  Leaves can be used in almost any location. However, the most popular location to use leaves is in a vegetable garden. Spreading piles of leaves throughout your garden has a two-fold benefit: You dispose of unwanted leaf material and build your garden’s soil!

Hay or Straw

Straw and hay are other types of organic mulch, which are most commonly used in vegetable gardens. Hay and straw can be spread out over established plants to protect the soil and retain moisture. This results in having to water your garden far less during the warmer months. Adding straw or hay to your garden also diminishes muddy conditions that can occur within your garden. Furthermore, once broken down, the straw or hay will add beneficial nutrients to your soil that your plants will love.

Synthetic/Inorganic Mulch

Synthetic (also referred to as inorganic) mulch comes in various types of materials. Although synthetic mulches work well for delaying the spread of weeds and retaining moisture, they do not break down and will not, therefore, add any beneficial nutrients to the soil.


Rock or stone is often used as a mulch. Most times, rock is used in areas that have poor drainage. Rock absorbs the heat from the sun quite well, so using it in areas which would benefit from the extra heat is ideal. As a mulch, rock does not retain moisture, but it does help channel excess water away from areas that are overly saturated. Obviously, rock or stone is heavy, so it is, therefore, difficult to move to or remove from an area; this is why it is extremely important to be sure in your decision to add it to your landscape.


Another form of synthetic mulch that is often used is plastic. Plastic helps heat the soil, so it is often used to in gardens to increase the temperature of the soil, so planting can be performed earlier in the year. The heat that forms when plastic is placed on the ground kills off weed seeds before they can germinate; it can also kill off desirable plant seeds as well. That is why it is important to note that plastic is impermeable, which means the moisture will not be able to pass through. Therefore, it is essential to perforate areas of the plastic to allow moisture to reach the soil.

Rubber Mulch

Another popular synthetic mulch is rubber mulch. Rubber mulch is made to look like bark and comes in a variety of colors to choose from. It can be used in almost any location, but we recommend not adding it to your vegetable garden specifically. Rubber mulch, like plastic and rock, does not break down (or breaks down incredibly slowly). So it is important to ensure you’re committed to this style of mulch because if you decide you do not like it, it will have to be removed manually. If you decide you want rubber mulch, it is important to remember that, since it does not break down, it will not add any nutrients to the soil.

Now that you have a better understanding of what mulch is, you can make an educated decision about what type will work best for you. If you are in the Camas, Washougal, or Vancouver, Washington areas, and are still unsure about which type of mulch you should use or would like help ordering or installing mulch, give us a call today at (360)567-6399. You can also contact us here or fill out our FREE estimate request form online.



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