Why do gardeners place a ring of mulch around trees?
Mulch rings are used to protect young and transplanted tree roots. Mulch is a very useful material in the garden. It discourages grass, protects against frost, and can be quite decorative. But it shouldn’t actually touch your tree trunk. A good mulch ring is a learned skill, and today, we’re here to tell you everything you need to know about creating a mulch ring around saplings and recently transplanted trees.
Why We Give Trees a Mulch Ring
How Tree Roots Grow
Tree roots are an incredible system. Curling through the soil, they both secure and aerate the land. This allows them to absorb both water and oxygen. Old trees have root systems as deep and wide as the branches, if not larger. However, a sapling and a recently translated tree with a truncated root ball need time and protection to spread out into the nearby soil.
For your young tree to grow healthy and strong, the roots will need 100% of the available resources in the surrounding soil. The right mulch ring is how you secure those resources for your tree.
Healthy Tree Trunks and Bark
Trees drink water from the ground, but most need to keep their bark dry most of the time. If a tree trunk is surrounded by damp soil or smothered in mulch, it can grow sickly. This is why we make mulch rings a few feet away from the tree instead of mulch circles or discs. Your mulch should not touch the tree trunk, though older trees may have large roots that grow up into the mulch ring. At this point, the tree is strong enough to share some root space with mulch and grass.
Keeping the Grass At Bay
Grass is pretty aggressive in its tiny way. If given a chance, it will grow right over the earth you filled back over your tree’s root ball. This wouldn’t be a problem -and can be pretty – except that grassroots compete with your young tree’s roots. In fact, grass can cover your tree’s access to oxygen by forming a mat over the top layer of soil This is bad news for your little tree and will slow its growth.
Protecting Tree Bark from Trimming and Mowing
Allowing your grass to grow up to the tree trunk also puts your young bark system at risk. Trees transfer moisture through a layer just below the outer bark. So nicking your young tree with a trimmer line or lawn mower can harm and even kill it. Your mulch ring not only keeps the grass at bay, it also ensures that the bark is safe from being clipped.
How to Lay a Mulch Ring Around a Tree
A good mulch ring is essential whether you have just planted a tree, are nurturing a natural sapling, or just want to properly landscape around the mature trees in your lawn. Following this guide will help you keep your tree’s roots healthy, safe, and not competing with any other plants for nutrients.
1. New Trees: Cover Over the Root Ball with Soil
If you are planting a new tree, the first step is to place your root ball in the hole you have dug and cover it over. Do not pack the soil, instead tamp it down to recreate ground level. This level will likely be two to four inches below the grass level.
2. Lift Away Grass Up to 3-Feet from the Tree
To remove the grass, use a flat-edge shovel to cut down about 2-4 inches and lift away the grass with the top layer of soil, roots, and all. You can even save and transplant the pieces of sod if you choose.
New or existing tree, you want to remove all the grass within three feet of the trunk – in a circle with a 3-foot radius or a 6+ foot diameter. For existing trees, some clear out to the “drip line” which is the area shaded by the branches. Either is fine, but young trees need at least three feet free of competition from grassroots and ground cover on all sides.
Be careful not to cut into the roots of your tree, especially for trees already growing.
3. Place a Ring of Edging to Stop Grass Regrowth
You will want a roll of edging the length of your ring circumference. Simple roll-top plastic ending is very serviceable. Push the blade of the edging into the ground deep enough to block grass roots all the way around the ring. The edging will prevent grass from growing up through and around your mulch.
You can also use decorative edging, provided it is known to effectively block grass progress. Decorative rocks, pavers, and other landscaping accessories can make mulch rings beautiful and integrated into a greater landscaping design.
4. Dig a Shallow Trench Against the Inside Edging
To help keep the mulch in place, dig a trench up against the inside of the edging, defining the inner edge of the mulch ring circle around your tree. This trench only needs to be a few inches deep and wide to create a more stable barrier.
5. Place a 3-4 Inch Ring of Mulch Around the Circle
It’s time to lay your mulch! Your mulch ring should start at the edging and end about three feet from your tree – and this area can be as large as your landscaping design provides for. Trees can grow happily in a mulched landscape with no grass or in rings with grass nearby.
Your mulch should be about 3-4 inches thick in fluffy wood chips, shavings, and/or pine needles of your choice.
Pro Tip: Do not cover your root ball area in mulch or pile mulch against the trunk. These are very common mistakes but are not good for the tree. Mulch can deny oxygen through the soil or hold moisture against the trunk – but without competing roots or the impetus to spread.
Enjoy a Healthy, Growing Tree
Now that you have laid a mulch ring, your tree’s root ball will have all the nutrients, moisture, and oxygen from the nearby soil without competing with or through the grass. Your tree will be better able to spread its roots and build a firm foundation in the new soil, growing faster and healthier than it would otherwise.
Whether you have a mulched landscape or are carefully building mulch rings in a grassy lawn, your tree will reward effort with beauty. To explore mulch rings and other elegant landscaping designs for your property, contact us today. The Fit Turf team takes special consideration for yard and outdoor space, and you can bet every tree will have a perfect mulch ring.