Organic tree care is like the other parts of our organic landscape and garden system. The key is caring for the soil and letting the soil care for the plant, in this case, your trees.
Happy and healthy trees
Healthy trees, by and large, don’t easily succumb to insects, pests, and diseases. Stressed trees are like magnets for insects, pests, and diseases. There is a reason this happens. Pests and diseases are natures way of taking care of weak and diseased plants. These plants are removed naturally to give healthy plants a better opportunity to grow and mature while returning the nutrients stored in the sick plant to the environment. It is the natural ecological cycle. The trick is to keep your plants happy and healthy, especially your trees. Trees are probably the biggest investment most people make in their landscapes. Trees are the only part of a landscape that can add value to the property. It behooves anyone to take care of this important and long-lasting part of our landscapes.
Stressed plants are almost always a reflection of environmental issues They are either getting too much water, not enough water, too much fertilizer, the wrong kind of fertilizer, are being treated with toxic pesticides, the soil is unhealthy, or the tree is planted too deep. In many cases, it is a combination of these that lead to the biggest problems.
Another problem is people planting species and varieties that are just not suited for the area in which they live.
We try to keep our systems simple and straight forward.
Organic Tree Care System
Stop using synthetic salt-based fertilizers, pesticides, and herbicides.
If you spray a toxic pesticide on your trees to kill or prevent insect infestations, that same pesticide will kill the beneficial organisms in the soil. You are effectively sterilizing your soil. If your goal is to have healthy soil, which is the foundation of healthy plants, then you can not continue to use toxic chemical-based synthetic products on your landscape.
One of the worst things you can do for your landscape is to apply a combination product that we commonly call weed and feed. The weed treatment part of these products is a broadleaf systemic poison. If this stuff kills weeds, it will surely kill any other broadleaf plant in your landscape. Trees are broadleaf plants.
Trees are usually planted too deep
Most of the trees that I see in landscapes around town are planted too deep. This may have been done when the tree was planted or may be the result of infill that occurs over time. Whatever the reason, trees should have a portion of the root flare exposed. The root flare is the point where the tree bark begins to transition to root. Covering the root flare keeps this part of the bark moist and susceptible to a host of diseases and pests, can lead to root girdling and inhibit the growth of the tree. Exposing the root flare on large trees is a job best left to professionals with specialized tools. Smaller trees can be done by the homeowner. However, it should be done with great care to prevent damage to the tree.
Aerate the root zone
The root zone of most trees planted in urban landscapes is compacted. It is important that the soil be able to breathe. DO NOT TILL AROUND YOUR TREES! Disturbing the soil by tilling, plowing or ripping destroys the microbiome and can injure the larger feeder roots of the tree. On many species of arid landscape trees, the system of roots lay just inches below the surface of the soil.
The best method is to use a fork or a core aerator to punch holes into the soil. Core aerators are designed to pull a small plug of soil out of the hole, leaving a space for air and water to infiltrate.
Another method of aeration is to spray a hydrogen peroxide solution on the soil around your trees. Mix drug store hydrogen peroxide (3% solution) 50/50 with water and apply at a rate of 1 gallon per 1000 square feet. As the hydrogen peroxide breaks down in the soil, it releases extra oxygen into the soil and helps flocculation.
Feed and Amend your Soil Organically
I like to top-dress the soil around my trees with a mixture of rock minerals, cornmeal, dry molasses, and compost. The rock minerals such as greensand or decomposed granite add needed minerals and grit to the soil. The cornmeal is a natural disease fighter. The cornmeal and molasses provide a quick sugar boost to the microbial life in the soil, encouraging them to multiply. I apply this treatment to my landscape in the spring and the fall. The spring application is made just before the trees start to bud out and the fall application just before the trees start to drop leaves as they go dormant. This provides a boost to the tree in the spring when it is emerging from dormancy and a reserve of nutrients when it is getting ready for winter.
The best method is to apply a one-inch layer of the amendment mix over your landscape and under your tree canopy. If you do not want such a thick layer, spread the mixture over several applications, allowing the material to work its way down and into the soil before making another application. This can be done on turf. Not only will your trees benefit, but your turf will get the same added boost.
Feed with Compost Tea
We routinely feed all of our landscape plants with compost tea. We often add some orange oil if we are having insect problems. We use the compost tea as a foliar spray and as a drench in our beds. Use the compost tea generously. You can’t overfeed with it. I make five gallons of compost tea and then filter it to remove the solids so I can spray it with a tank sprayer. If you don’t filter it well, it will continually block the tip of the sprayer. Once I have my compost tea ready, I mix two cups of the compost tea with a gallon of water in my sprayer. I add about two tablespoons of liquid dish soap as a surfactant. I then spray everything. Every plant in our landscape gets a good spray of this mixture. We even bring our potted plants outside and give them a spray and a good dose of sunlight.
After you have sprayed, you can pour the remaining liquid directly into your beds as a drench. Pour it around the circumference of the canopy of your trees as well.
Treat wounds or damage to tree trunks and limbs with tree goop
Tree goop is a mixture of equal parts of rock phosphate, diatomaceous earth, and compost. Mix the dry ingredients with enough water to make a slurry that is thick enough to stick where you put it. Slather the goop on wounds, cuts, splits or evidence of insect damage like borer holes. Put it on thick. It will eventually wash or weather off. Mix some more and keep the damaged spots covered until they heal. The goop makes great fertilizer as it weathers or rains off and hits the ground.
Overwatering is one of the biggest problems with most trees. Landscape trees tend to be planted in areas with other ornamentals. Flowers take more water than trees and putting flowers around the base of a tree is an invitation to overwatering. We recommend that you never put a flower bed under or around the base of a tree.
Another culprit to this overwatering is automatic sprinkler systems. The problem is that we often see a shade tolerant grass such as fescue planted under trees in the landscape. Fescue requires much more water than most trees, so you are building an incompatible landscape. It can be managed, but the use of an automatic irrigation system is not the answer. Water only when your landscape needs the water. Turn off that automatic control and water based on what the soil and the plants are telling you, not the calendar and the clock.
Organic Tree Care in Summary
Organic tree care and management in an organic system are much the same as caring for the other parts of your landscape. A little common sense and some attention are necessary. Remembering our mantra, Feed the Soil, Not the Plant, will tell you a lot about what you should be doing, when and how.