Rebel Roots

 Tree Health After Extreme Weather

Extreme weather events over the last several years, including freezes, excessive heat, and drought have left trees stressed, damaged, and more susceptible to disease and pests like Oak Wilt and the dreaded Emerald Ash Borer. Like most things, though, if we look at them holistically, we can take steps to heal. Future damage can be mitigated, and current injury healed by proper fertility and a healthy soil microbiome which is critical to plant health. Species diversification is also important to help slow disease and pests.  

By far, the most important element of tree health is the soil microbiome.  No one really wants to spend a bunch of time talking about soil composition and the critical organisms, especially the microorganisms, that inhabit it. Well, except me. It cannot be overstated that without healthy soil you cannot have healthy plants. The microbes have a symbiotic relationship with plants. Microbes get carbohydrates, plants get minerals. The microbes metabolize the minerals and nutrients and make them available in a form the plants can use. Further, a healthy microbiome will keep pathogens in check. In most cases, plant disease is not really due to the presence of pathogens- it is due to the absence of a healthy microbiome to keep them in check. Create a microbiology friendly landscape. Use organic fertilizers with a hefty package of microbes; I love MicroLife products- their Acidifier Fertilizer is great to balance our alkaline soils and water but will not burn and is good for everything- turf to trees. Avoid using fungicides and insecticides. Apply granular Humates to turf and beds and around trees to improve soil quality.

As with investments and shoe collections, diversification is the smart play. We have plenty of Live Oaks. As a horticulturist and landscape designer, I rarely use them in my designs. When there is a high concentration of a species in any environment, when something goes wrong, numbers are decimated. If you have 9 trees in your yard, and only one is an oak and gets oak wilt, that is sad, but not as devastating as it would be if all 9 were oak. When an ice storm hits, some trees fare better. If you have a greater concentration of a type that is hit hard, more damage is sustained. I am not suggesting you remove healthy trees to replace them with something different- established trees are too valuable. But if you have an opportunity to choose a new tree to replace one lost, or are choosing for a new or refurbished landscape, consider something else. Mexican Sycamore, Big Tooth Maple, Magnolia, Bald Cypress, and Chinese Pistache are great choices.

Fertility is also a critical component for tree health, especially for trees trying to recover from stress or damage. To recover from damage, fertilize with a slow-release organic fertilizer. Why organic? Think of it this way. I am sick. I eat a Moon Pie. I get a little burst of energy from the sugar. Then nothing. Conversely, I eat lean protein and some great nutrient dense veggies. My system has the strength to heal. Synthetic fertilizer is a Moon Pie. Organic is health food. Your trees don’t need a quick burst of energy. They need slow, steady nutrients. Nothing happens fast with trees. Damage takes years, even decades to show. Recovery takes a while, too. Organic fertilizers also bolster microbiology. We have come full circle.

To help your trees recover, fertilize and build your soil and soil biology. I’d go out on a limb (yes, I just said that) and say most every tree sustained some damage. We need to fight pathogens and give trees every advantage we can. Diversify. Give them slow, steady health food in the form of organic fertilizer. And do everything you can to protect and grow the microscopic workforce that takes care of your trees. Give the trees these advantages, and their own natural process will help them heal so you can enjoy them for decades to come.