Vertical Mulching

Discussion in 'Maples' started by JT1, May 11, 2017.

  1. JT1

    JT1 Rising Contributor

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    Euclid, OH USA
    This time of year it is easy to spot soil problems. Maybe you should have re-potted this Spring, but did not have time. Maybe you did re-pot and now you realize your soil mix is retaining too much water. Maybe the soil is becoming too compacted. Many times soil issues are a result of not enough oxygen or not enough nutrients getting to the roots.

    A tree that has stopped growing or a canopy that is sparse, with no back budding or branches that only have foliage at the tips are all signs related to soil issues. These issues can occur from soil compaction limiting water, oxygen, and nutrients from getting into the root zone. Or soil that is retaining too much water which limits the oxygen required for the roots to take up water and nutrients. Vertical Mulching resolves these issues and restore energy reserves and vigor to your tree.

    Vertical mulching will fix problems with oxygen, moisture, and nutrients. It will restore balance to your container soil or landscape soil.

    How to vertical mulch, tools and techniques...

    Vertical mulching creates vertical shafts in the root mass to ensure oxygen, moisture, and nutrients can evenly penetrate into the root mass that is lacking due to compaction or a soil mix that is too moist.

    What is needed to make a vertical mulch mix, components and tools.
    My mix consist of 3 components. Organic material, aggregate, and fertilizer. Must be free of silt or fine dust. All Need to be about the size of coarse coffee grounds, not fine espresso ground as that is too silty or dusty and will block oxygen and moisture; if the components are too big it will allow too much oxygen into the roots or may even block the mix from properly filling the shaft.

    I use the following.

    -PHC ROOTS 7-7-7 fertilizer. All organic, slow release with added beneficial bacteria and microbes that improve the health of your pot mix and your tree. This is hands down the ONLY fertilizer that I will use on maples. I have been using for 4 years after a 10 year hands on research project on fertilizers. This fertilizer is available from AM Leonard.
    A.M. Leonard Tools for the Horticultural Industry since 1885.

    -Sharp silica sand or similar aggregate. Again its important that its the size of coarse ground coffee and not too fine like play sand or too large like pea gravel.

    -Pine fines, also sold as soil conditioner. This is free of any silt, soil, and peat. The pine fines act as organic matter that helps retain moisture, without staying too wet or drying too quickly. It helps provide a healthy balance of moisture and oxygen.

    -A 6" L x .3 to .5" W pointed spike or medium to large Phillips-head screwdriver of similar size.

    -Mixing bucket

    mix 1/3 pine fines to 2/3 sharp silica or aggregate. Use 1/3 to half the recommended PHC roots fertilizer amount for your tree or container size. Add this to your mix, but be sure that the amount is no more than 1/3 of your mulching mix (fertilizer is no more than 1/3 of the total pine fines and silica sand mix) Mix everything together in your mixing bucket and when you take a scoop as a sample you should see an even consistency of Silica sand, pine fines with a lesser amount of fertilizer present to ensure it is well mixed.

    Measure the length from the trunk of your tree to the inside pot wall and divide by 3. For example lets say the inner pot wall to the trunk is 6". Divide by 3 and you get 2". Grab your spike and position it 2" from the pot wall and in the 12 o'clock position. Push the spike into the soil gently and rocking it back and forth gingerly to avoid damaging roots. make a hole that is 1/2 the depth of the pot. We do not want to go all the way to the bottom. It should be atleast 3" deep but not more than half way the totla depth of the pot. Most pots will allow you to go 4" to 5" inches deep and that is deep enough as most feeder roots occur in the first 3"-4" of surface soil. Rock the spoke in a circular motion so that it make a hole that is between the size of a nickle or quarter. Pull the spike out. Fill the hole with your vertical mulching mix about half way. Use spike to gently tap the mix in, then fill to the top of the hole and create a slight mound at the surface no more than an inch above the surface soil.
    Move your spike to the 3 o'clock, 6 o'clock, and 9 o'clock positions and repeat. Keep in mind that the hole should not hit the pot wall. If pot tapers inward, do your hole at an angle inward so that it does not hit the pot wall. We want water penetrating the soil mass and not escaping down the pot wall. Water the pot and if the mix settles, add more mix and water again. If soil is severely compacted you can use a thinner spike to gently aerate the surface area of the root mass penetrating 2" down but don't widen the hole like you do when making the hole for vertical mulching. The following year these steps can be repeated in the 1:30, 4:30, 7:30 and 10:30 positions or in-between the vertical mulching holes made from the season before. Or for very large pots you may want to vertical mulch in all the positions mentioned above.

    Additional fertilizer and mulch can be added to the root surface just as long as the cumulative fertilizer application does not exceed 1/2 the recommended dose.

    Please note that vertical mulching as described above is not just limited to container grown trees. The technique can be used for landscape grown trees too. It will improve the overall health of the tree increasing vigor and promote back budding and fullness in the canopy.
    Last edited: May 11, 2017
    kgeezy20 likes this.
  2. AlainK

    AlainK Well-Known Member Forums Moderator Maple Society 10 Years

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    nr Orléans, France (E.U.)
    Actually this is more or less what I do with the bonsai I didn't have time to repot : gently make holes with a chopstick, and fill the holes with free-draining mix (fine pozzolane 3-5 mm, akadama 3-5 mm and a little composted bark). Then the roots get more oxygen, the soil is not as compact as before.

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