How To Mulch Around Trees The Right Way

Mulching adds incredible benefits to your garden. It’s a game-changer for soil health and fertility, not to mention its role in keeping the soil moist and managing those tricky temperature changes.

But here’s something crucial I learned along the way – if done incorrectly, mulching can actually harm your trees.

Yes, you heard that right. There’s a practice out there called ‘Volcano’ mulching, which involves piling mulch right up against the base of trees. It might look neat or even seem like you’re giving your tree a cozy blanket, but it’s far from beneficial.

Many gardeners and landscapers, well-intentioned as they may be, aren’t aware of how damaging this can be. It can suffocate the tree’s roots, encourage rot, and invite pests and diseases. In a nutshell, volcano mulching could very well lead to your tree’s premature demise.

The Pitfalls of ‘Volcano’ Mulching

I’ve seen it time and time again, ‘volcano’ mulching, where mulch is heaped high around the base of trees. The volcano appearance is typically created from a raised circular garden bed around the tree. Mulch is put onto this bed and gets thicker and thicker the closer it gets to the tree. 

This creates a look that is as dramatic as lava spewing from a volcano. It’s an eye-catching practice, but here’s the thing – it’s not doing your trees any favors.

Mulch volcanoes can seriously jeopardize your tree’s health:

  • Pests love them. Thick layers of mulch become the perfect hideout for pests, putting your trees under attack from both above and below.
  • Fungi find a home. When mulch piles up, it traps moisture and ups the humidity around the tree’s roots, creating a paradise for harmful fungi.
  • Trees get suffocated. An overabundance of mulch insulates too well, cutting off the tree’s supply of oxygen and nutrients. This can stunt growth and, in the worst cases, kill the tree.
  • Root rot becomes a risk. Trapped moisture leads to damp conditions, which can rot the tree’s roots. Conversely, too thick a layer can prevent water from reaching the roots at all.
  • Collar rot can occur where the stem meets the root, weakening the tree and leaving it vulnerable to disease.

Why, then, do we see so much volcano mulching?

First off, it has visual appeal. A neatly piled ring of mulch around a tree can look striking. However, the aesthetics don’t justify the damage.

Communication gaps among landscapers also play a role. Without proper guidelines or under time pressure, workers might not apply mulch in the best way for tree health.

The practice of over-mulching also continues because its damaging effects are not immediately visible. You’ll notice that a lot of the symptoms due to over-mulching occur from below the tree, so they may not be apparent at first. Thus, incorrect mulching around your trees can be a silent killer.

Lastly, it’s a cycle of imitation. Seeing others pile up mulch around trees, landscapers and homeowners alike assume it’s the correct approach, unknowingly perpetuating harmful practices.

The Right Way To Mulch Around Trees

As you know, mulch benefits your garden – trees included. Therefore; it’s definitely worth mulching near your trees to support their health.

The answer is not to stop mulching but to mulch the right way.

Keep your mulch no thicker than 3 inches and never up against the tree itself.

There’s a sweet spot right around the trunk – the root flare – where you need to maintain a little breathing room. Aim for a two-inch gap here. It might seem like a small detail, but it makes all the difference.

Some gardening pals suggest keeping the mulch even thinner, almost like a gentle covering, within a foot from the trunk. This approach ensures the soil benefits from the mulch without risking the health of your tree.

Are Some Mulches Better For Trees?

Are Some Mulches Better For Trees

Now, onto the big question: Are some mulches better for trees?

Absolutely. Organic mulches like wood chips or bark are champions for trees. They’re not just sitting pretty; they break down over time, feeding the soil with essential nutrients your tree will thank you for.

Younger trees, thirsty for nutrients, do well with shredded mulches such as straw, leaves, or grass clippings. These types decompose faster, giving a quick nutrient boost, but remember, they’ll need topping up sooner.

As your trees gain wisdom and age, switch to the stalwarts of the mulch world – wood chips and bark. They last longer, continuing to enrich the soil as they break down gradually.

How To Tell If My Tree Is Damaged From Over Mulching?

Figuring out if you’ve been a bit too generous with the mulch isn’t hard. You just need to know what signs to look for:

Off-color foliage: If the leaves of your tree are not their usual vibrant color and instead appear dull or discolored, this might be an indication of over-mulching.

Stunted growth is a big red flag. If the leaves are looking more petite than usual or the twigs seem weak, it’s a sign that the roots might not be getting enough oxygen. That cozy blanket of mulch could be suffocating them instead.

Another telltale sign of a lack of oxygen is the presence of secondary roots or girdling roots.

Girdling roots are roots that grow around the trunk of a tree in a circular or spiral pattern. As both the tree and root expand in diameter with time, the root can encircle and constrict the trunk, limiting the circulation of water and essential nutrients within the tree. This can lead to a decline in the tree’s health, instability, and even premature death.

Dieback of older branches: This problem is due to waterlogging and root suffocation because of excessive mulch. This will kill the tree over time due to a lack of nutrient and water uptake and the spread of diseases. The term die-back refers to the death of branches and twigs from the tip downward.

Softening of the tree’s bark at the base: Lastly, if the bark at the base feels soft, that’s not a good sign. Too much mulch piled against the trunk can lead to decay, opening the door for infections and pests.

If you notice any of these signs, it’s important to take action immediately to remediate the over-mulching and give your tree the best chance of recovery.

Repairing An Over Mulched Tree

Repairing An Over Mulched Tree

If you’ve noticed your tree suffering because of too much mulch, don’t lose hope.

While it’s true that “mulch volcanoes” can cause significant harm over time, with some trees showing damage after just a few years and others hanging on for much longer, there’s often a chance to turn things around.

The first step in the recovery is to remove the excess mulch. How you go about this will depend on how long the tree’s been over-mulched and whether or not girdling roots have formed.

Sometimes, a simple rake will do the job. In more complicated situations, an air spade might be needed. This nifty tool can expose those troublesome roots without harming the tree itself.

Next up, carefully prune the girdling roots. It’s a delicate process, but necessary to give your tree a fighting chance.

Once you’ve dealt with the roots, it’s time to reapply the mulch – correctly this time. Remember, no more than a 3-inch layer and keep it away from the trunk! A bit of extra watering may also do wonders to help your tree bounce back.

Signs That Your Tree Might Be Too Damaged

Despite our best efforts, some trees can’t be saved.

Look out for these signs: significant die-back in the crown, rot at the base, large patches of missing bark, signs of fungal infection, or girdling roots that are just too big to handle.

If the tree’s vascular system is badly compromised, affecting more than a third of its canopy, it might be time to say goodbye and consider planting a new tree. Remember, gardening is as much about new beginnings as it is about nurturing what we already have.

How To Safely Recreate Mulch Volcanoes

You’re probably intrigued by the dramatic look of mulch volcanoes that many gardeners rave about.

I get it, the visual appeal is undeniable, but here’s the thing — we want to keep our trees healthy while indulging in this trend. I’ve got you covered with two smart approaches.

First off, consider raising the soil level before you even plant your tree. It’s like crafting a mini hill in your garden. This method gives you that volcanic appearance without risking the health of your tree by piling mulch against its trunk.

Alternatively, lowering the ground around your tree is another clever tactic. By digging a trench ring around your tree’s base, you’ll create an illusion of elevation for the mulch, making it stand out against the landscape without harming your beloved tree.

Both of these methods allow you to achieve that sought-after ‘volcano’ look safely.

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