The Garden Decoder: What Is ‘Ramial Mulch’?

When mulching your garden, you have many, many choices: shredded hardwood, pine needles, straw, and seashells, to name a few. One of the most common materials used for mulching is wood chips. But not all wood chips are the same. There are bark chips made from the bark of pine trees, which are very attractive and tend to last a very long time. There are industrial wood chips that are made from pallets and waste wood, which is not recommended for use in vegetable gardens due to the possibility of leaching chemicals. And there is one type of wood chips that you probably have never heard of: ramial mulch.

N.B.: Featured photograph above by Monica Willis for Gardenista, from My Garden Story: A Secret Rooftop Oasis on Manhattan’s Upper West Side.

What is ramial mulch?

Ramial is from the Latin word for branch. Ramial mulch is a type of wood chips made specifically from young hardwood tree branches that are up to about two and a half inches thick. (In some cases, shrubs are also included in this description.) In the late 1970s, Laval University in Quebec researched if there could be a use for this lumber byproduct and they found one. Another name for this mulch is BRF, an abbreviation for its French name, bois raméal fragmenté.

What makes ramial mulch special?

Because the mulch is made from the youngest of branches, it is full of nutrients and minerals, as most of the tree’s resources are directed to those fast growing branches. This makes them an  almost a perfect food for your garden. Ramial mulch is essentially a mulch that also works as a soil amendment.

What are the benefits of using ramial mulch?

There are more than a few benefits! First, they are chock full of all the good stuff that goes into making plants grow. Second, they are small, and break down faster than most mulches. And third, fungi and bacteria love it and start to break it down quickly.

What are the cons?

As mentioned above, it’s almost a perfect food for your garden—almost because the process of breaking down the ramial chips “steals” available nitrogen from the soil. And when gardeners hear that, they tend to not like it at all. But with most things gardening, it’s not that simple. Yes, the bacteria take nitrogen from the soil, but they are really just borrowing it. Once the decay process is complete and the chips have become humus, the nitrogen is released back into the soil. Keep in mind, too, that mulch is on top of the soil. Your plants’ roots are deep below the top inch of soil where all of this is happening, meaning established plants won’t be affected.

Where and when should you use ramial mulch in your garden?

You can use it at any time in established beds, but don’t add it to your vegetable beds or beds with seedlings during the growing season because of the nitrogen issue. Wait until you’ve cleared them in the fall to add it. This gives it time to break down and have the nutrients available in the spring.

How do you find ramial mulch?

Since it is a lumber byproduct, ramial mulch can be hard to find if you aren’t anywhere near commercial logging locations or near Canada. You will need to be a bit creative. Contact your arborist. In their process of trimming trees, they could offer you the chipped trimmings. This may also include larger branches. Your local fruit orchard may also be able to provide ramial mulch. Or, you can make your own by renting a chipper and feeding it the prunings from your yard.

See also:

• 5 Things Nobody Tells You About Mulch
• The Garden Decoder: What Is Green Mulch?
• Gardening 101: When to Use Compost, Fertilizer, and Mulch