Lisa's Landscape & Design

Saving the Planet One Yard at a Time
Mycorrhizal fungi in mulch

Mulch, It’s Not Just Pretty

Mulch is a very undervalued commodity in our garden space. This is one of those area’s where I seem to get the most resistance. You will hear me say, 4″to 6″ over and over again as I speak about gardening. There is a very valuable reason for this.

Most of us have yards that have rock, builders sand and other hardships for your plants to contend with. Isn’t life hard enough for our little plants here in Central Texas to at least a fair advantage? I have spoken about compost and will again many times, remember…”Compost can save the world”. Today however, we are going to discus the value of mulch.  I use compost as my mulch in the spring as it adds nutrients and most organic compost’s are made up of shredded wood and decomposed matter which serves and an excellent mulch.  Mulch is important for a number of reasons. One being that the barrier it provides keeps weeds at bay, it is a moisture retainer and finally, it protects the plants from the heat burning away at the ground which aside from zapping the moisture, also destroys/steals the nutrients and nitrogen. This depth of 4-6″ of mulch plays a huge part in all of this. This is not to suggest that you would add this much mulch each year, but that you would maintain this depth over all.  By placing a shallow depth of mulch, you have far more weeds, moisture and nutrient issues, than you do without it. Simple as that. The depth recommendation comes from years of experience by gardeners and Master Gardeners and should not be taken lightly.

Now a couple of tips on how to apply and where. One important point to remember, never place mulch up to the top of the foundation of your home which is where your weep holes are located. You should have a minimum of 4″ between the top of your foundation (where foundation meets house) and the top of the mulch. Mulch has a lot of little insects housing in it and you don’t want to encourage them to make the wood in your home a new nesting place. Keeping a safe distance from the mulch layer to the top of your foundation prevents this.

Also very important is how to apply mulch around trees. NO Muffin tops and no tree Volcano, we are not trying to build the great pyramids out there. Piling your mulch up high around the tree flair (or bell shape at the base of the tree, where the tree hits the ground), encourages bad fungus and wood borers. You want  to create what is called a “berm” or “well” around trees under two years of age and a flat circle level with the ground around mature trees. The young trees collect water at the base, older trees collect water at their canopy or dripline. The well for saplings and newly planted  mature trees should begin at least 4-6″ away from the trunk of the tree, then make a berm or mound in a circular fashion around the parameter to help with that collection.

This is a great example of a Badly mulched tree, this should have a well around the tree with the tree “Flair” or bell shape visible in the center of the berm. Your tree should never look like a stick coming out of the pile. This is bad tree care, all around and it’s ugly.

The berm need only be a few inches tall, I have seen some that are a foot tall, and this isn’t necessary, it’s also a good way to squeak me more money from you for nothing.

Mulch berms around trees are valuable for a number of reasons, like I said previously, they are a weed barrier, water and nutrient protector. Also Important to note, is they create a barrier between them and your lawn tools. Weed wackers and lawnmowers are not our tree’s friends. Quick side bar to a bio lesson… The trees vascular system is just beneath the bark, at about 1/4 inch in depth. when you scar a tree at that depth, you have cut off its Xylem and Phloem (vascular). That means it can no longer transport food and water. This can be death to a tree part or worse as the injury to an Oak can result in Oak Wilt and for others may be a gateway to a fungus or borer that can be the demise of any tree. Frankly, once a tree is older than 3, it really no longer requires a berm, the mulch only serves as a barrier at this point and about 2″in depth  is ample. Make these rings as big as possible in your space because let’s face it, you aren’t going to find sod under any tree in the forest. 

Mulch comes in all sorts of fancy colors and shapes. Do not use colored mulch unless you know its source. Most of the colored mulch are not organically colored, they use chemicals to produce these unnatural hues and can be harmful to the plant. If you have drainage issues, use a hardwood shredded mulch, these will have less chance of floating away. The large mulch bark has its function but it makes a great little boat in heavy rain and it encourages bugs to live amongst it, particularly large cockroaches and crickets, so be careful if you are using it close to the house. Pine straw is an excellent mulch for the TX garden to help add acidity to our other wise alkaline soils and you can find it at most local nurseries. I do not recommend the cocoa mulches as they are dangerous to animals and be a problem for a dog who might eat it. Also, consider the convenience of having a load of mulch delivered over hauling bags, if you have a large job, a delivery in bulk may be a better option and more cost effective. You measure the length and width of the bed and the desired depth and the landscape service will give you the calculated quantity.

Once your beds are prepared, add a “top dressing of about 1/4 – 1/2” of mulch each fall to maintain the depth. You will lose more than you would think to run off, wind and decomposition, not to mention the air takes its share to carbon. I compost and mulch my beds in the spring and compost and mulch in the fall, every year like clockwork.  This is a great way to encourage growth in the Springtime and winterizes snd feeds roots on dormant s plants and trees while it protects your plants in the Winter.

Happy Mulching!

Lisa LaPaso

Lisa’s Landscape & Design

“Saving the Planet One Yard at Time”

1 Comment

  1. Thank you so much for sharing all this wonderful info.

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