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How to Properly care for your Oak Trees

How to Take Care of Your Oak Trees

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How to Properly care for your Oak Trees


Got Oaks?


Then you probably are not properly taking care of them!


Many folks are over watering and fertilizing them incorrectly.


When was the last time you took a beautiful long country drive? Notice those oaks on top of a nearby mountain? I wonder who is watering and fertilizing them? I have a worker that insists that trees do not need water. That is incorrect. They need water just like all other living beings need water. However, too much water is bad for all of us. Many trees have developed over the millions of years, each in accordance with where they live. There are hundreds (600 actually) of Oak species (Quercus, is the oak tree genus). Some oaks are deciduous, while others are evergreen.



Oak trees like a Mediterranean climate : dry summers and wet winters, with some liking arid desert-like regions, and some liking subtropical rain forests. Our California oaks have adapted to a Mediterranean climate but eastern oaks, such as the white oak, grow in a wide range of climates. 


Oak Trees have both a deep central root system (not a tap root) and a branching roots system within the top 2 feet of soil which extends out at least 10 feet past the trees Drip Line. You can tell the basic root system structure by looking at the oak trees branches. The root system mics the top branches!


I like today” As above, so below.” This is especially true in Oak Trees. The main difference is that they have a deep central root system. Not all Trees have a single taproot.  Most trees do not have tap roots after their initial growth stage. Instead, they make water-seeking lateral and feeder roots. If the tree is growing in deep, well-drained soil, these trees develop deep roots surrounding the trunk.

These are not the same as a taproot. Oak trees do not have deep tap roots but have massive lateral and feeder roots. These roots should be well below the water table. If the same Oak is growing in bad soil or in conditions similar to what we have here in Malibu (hardly any real soil, depending on what area it is in), then these roots will be above the water table, and the tree is dependent on other water and nutritional sources. Many local Oaks rely on the coastal fogs for their source of water and or local streams.


Many folks think that the Oak trees roots system stays under the tree's leaf canopy. Trees in a forest have roots that reach out beyond their branches and leaves in search of water and nutrients. Tree roots can grow a long ways laterally again depending on the soil. What the tree is doing is looking for sources of Mycelium which will provide the tree with its nutritional requirements. The Mycelium also needs a certain amount of water as well as other biological and elemental requirements. Trees communicate with each other through this Mycelium being. Tree roots not only intermingle with neighboring tree roots but also with the Mycelium. The Mycelium provides nutrition to the trees even if a tree is not in an area that it can get nutrition from, the Mycelium will send it the required nutrition! The same happens when a  tree is being attacked by a pest or disease, it is the Mycelium that warns the other trees to protect themselves.


Usually, one can determine root damage of trees such as oaks by observing the damage to that same side of the tree in its branches. The same holds true for watering one side only of a tree since that side will get the water to the roots while the roots on the other side will suffer and become damaged.  However, if Mycelium is present in the soil, it also means that the soil is alive and that it is not getting over watered. Too much water makes the soil waterlogged and kills off the Mycelium.


It is the "feeder" roots that are in the top 12 inches of soil that supply your tree with most of its food and some of its water. These delicate finer roots are concentrated in that upper soil and mulch layer where nutrients and moisture are available due to microbial activity. Again, this depends on the health of the soil with healthy soil allowing for deeper roots that search for water and Mycelium sources.



An Oak tree is drought-tolerant if it is over 3 or 4 years old and you should only water it once a month during the dry season and no watering at all if it rains. During a drought, your first reaction is to start watering more. You do that for your lawns etc., which is ok if done correctly but you do not begin watering your oak trees more! The trick is to set up a drip system or a subsurface irrigation system. Give your Oaks a good deep watering once a month. The length of time depends on what soil you have.


Many folks like to plant under the canopy of their oak tree, but this is a bad idea, and it will be harmful to the tree, especially if you are growing a California native oak. Many fungal pathogens cause the various forms of root rot, such as those in the Armillaria and Phytophthora genera, that are dormant in dry soil and only become active when the soil is warm and stays wet. There is basically no cure for these diseases once an Oak Tree gets its. Therefore it is better to practice prevention. I tell folks that all plant, tree diseases start in the soil. If you use chemical fertilizers, that will also kill the Mycelium as well as all beneficial microbes. That is one reason why oak leaves are so important to the health of the Oak.



Check out my new book “Don't Panic Its Organic.”






Any questions?