Trees are one of the most common types of plants we find in yards in Idaho, and are a big investment for most homeowners, and yet tree care is a subject of mystery for most people. The average homeowner, with whom I have worked over the last 10 years as an applicator, almost always tells me they know nothing in the way of what or how to provide care for their trees and shrubs. So here are a few tips to help you understand how to care better for your trees and shrubs.
Good Watering & Feeding Practices
The first misconception most homeowners have is that the sprinklers in their lawns will take care of watering their trees and shrubs. This idea is false. Sprinklers are rated and designed only to water at a depth of 3 to 4 inches to reach the root zone of the grass; whereas trees and shrubs need to be watered at a depth of 8 to 12 inches to reach and encourage deep root development. To water at the needed depth, I usually recommend setting your hose at a trickle and set it at the drip line of your tree or shrub (the edge of the canopy or the edge of where the leaves or branches are). You need to do this in a compass placement setting of north, south, east, and west with your tree being the center of the compass. Water for 30 to 60 minutes in each area of the compass—north, south, east, and west to saturation, where the water starts to puddle up. For shrubs, I recommend watering at base of the shrubs for 30 to 60 minutes to saturation. This should be done 2 to 3 time week for newly planted trees and shrubs and then 1 to 2 times a week for well-established trees and shrubs. This will give your woody plants the best access to the nutrients in the soil. Where Idaho soil is alkaline, it binds up the iron and nutrients in the soil and watering makes those nutrients available to the woody plants and helps to alleviate tree issues.
About 90% of the time; when a tree has an issue, it is in the root zone of the tree. Good watering practices are one way to help curtail these issues, but another “Best Practice” homeowners can do is to have a mulch barrier of 12 to 18 inches around your trees. Not only does this border help provide a location for watering and feeding of your trees, but it also to prevents mower and trimmer damage that can not only be unsightly, but extremely harmful to trees.
Another practice to help keep your tree healthy and strong is by feeding it twice a year in the spring and fall. This helps promote stronger and deeper root development; which in turn prevents your trees from falling over in high winds, and it also gives the tree the extra nutrients it needs. You see trees allocate the nutrients they store and take it up to use for growth, healing and defense.
Integrated Pest Management
When you see a tree weeping sap, it’s trying to defend against a boring insect that is trying to get into, or has gotten into it. With what is known as Integrated Pest Management, or IPM, professional companies can assist trees and shrubs in their fight against insects and low nutrient needs. IPM can be anywhere from a simple spraying program to control pests that harm a tree, a dormant oil spray to kill over-wintering insects and their eggs; deep root zone fertilizations and insect drenchings around the trees to help with boring insects, or direct injections into the trees for pest control and prevention.
When a tree or Pine gets boring insects into them, a systemic treatment is going to be needed to help control the pest. In Idaho, Green Ash Trees and Birches are the most common trees to get boring insects, but I have also seen them in Maples and Honey Locusts. Pines and Spruces will tend to get a boring insect known as Pine Bark Beetle. These trees all can benefit from systemic treatments, either as a treatment for active pests or for prevention so that if the pest gets into the tree then the tree will have the product there to combat the pest.
Pruning Best Practices
All these play an important role in tree care. Another, often less thought of, method that can help in the prevention of issues for trees and shrubs is annual pruning. If trees and shrubs get too overgrown, the wind cannot flow freely through the canopy, and then you start to deal with fungus’ developing on the leaves of the trees and shrubs. Anthracnose is only one of these diseases that can develop from poor air flow in a tree. Pruning helps to keep the air flow free and constant; which stops these problems. Pines also get diseases, therefore they would also benefit from pruning and an IPM practice of nutrient feedings, insect spraying, and a fungicide spraying program to help keep diseases like needle cast and needle blight from causing damage to your trees. Pruning is also our way of telling a tree or shrub on how we would like it to grow. The branches you trim off will tell the tree where to send the growth and nutrients so it will look the way you want.
Pruning is a tricky process, so unless you know what you are doing it is best to hire a company to come and trim your trees and shrubs. They have the knowledge to which and how many limbs to remove. Usually, a tree trimmer will focus on first trimming out dead, dying damaged and diseased limbs. Then they will remove any branches that are or will cross each other. This will cause damage and disease at later times, so it helps to remove the problem before it starts. Finally, the removal of little new growths inside the canopy will help with the airflow needed. Another factor to take into account is the type of tree you’re trimming. Some can be trimmed anytime, but others should be done in the fall. Maples are one of these trees. Their sap flow is strong in the spring and you can cause problems for the tree by pruning in the spring. Best to mark the limbs with ribbon loosely wrapped around and tied so know which you wish to trim during the spring and summer, and then trim those limbs after leaf drop in the fall.
A friend I know has said, “An ounce of prevention is worth a pound of cure.” This is definitely true when it comes to the care of your trees and shrubs. Benjamin Franklin said it first and the idea is sound in the Horticulture industry. Prevention is more ideal than trying to find a cure when your valued trees or shrub are starting to die.
So by watering regularly, preventing damage through an IPM program, and pruning regularly, you can keep your trees healthy and happy. Remember, these steps are ones you can either do on your own or you can ask a professional company to handle the pest management, and pruning. By understanding these care concepts homeowners and professional companies work every year to help care and prevent problems from taking and reducing the trees we desire on our properties.