February 19th, 2018

General Tree Care

Here are some tips to help you become a tree expert!

Location and Selection


When deciding to buy a new tree, the location in which the tree will go should be the first major deciding factor. Trees live for a long time, and while some may grow slower than others, and growth will reduce with age, they never stop growing. It is best to keep in mind how much space they will need, the soil and irrigation conditions, the wind conditions, and the amount of sunlight the tree will receive. Once all those factors are considered, then you can choose the right variety that will grow in those conditions.

The next step is to choose a healthy specimen. Form and habit are going to vary between differing species, but there are a few things to look out for in general when selecting a new tree. A tree that has well distributed and well spaced branches that create a balanced crown, and have wide angle branch crotches will help get you off to a good start and ease any further management down the road.

Planting


Dig a hole double the width of the pot, and the same depth, if not a little shallower, as they tend to sink with time and irrigation, the key is to not bury the zone of cell division, which occurs where the trunk begins to flare. Place the tree so it is straight, and back fill with the native soil dug from the hole, if the soil is mainly clay, you can add some organic matter, or compost (if it is not too hot) to the back fill, but no more than a third. You want to avoid creating a pot in the ground by adding too much soil amendments and discouraging roots to branch out into the native soil. After the tree is planted, mulch the tree in a doughnut fashion, making sure not to pile up mulch near the base of the tree.

Fertilizer is not recommended when planting a tree, if you feel the soil is very poor and want to give the tree some extra nutrients, a slow release fertilizer can be added, and/or mycorrhizal fungi, which can for an association with the tree roots, helping them uptake more nutrients.

 

Pruning

The reason for pruning trees is mainly for the health of the tree and to create a sturdy structure. After that is accomplished, then pruning for aesthetics can occur. Many people have different ideas on what is aesthetically pleasing, but some of those ideas can be detrimental to the health of the tree and are discouraged on this page. When pruning, always make correct pruning cuts, and avoid reducing the trees overall canopy by more than 1/3. The best time for pruning most trees is in the mid to late winter, when the tree has gone into dormancy and stored it’s nutrients for the year, unless it is coniferous tree*. Pruning is quite simple once the process is understood, but for beginners, we recommend getting some hands on education and taking a class. Keep an eye on our schedule of events for an upcoming Japanese Maple Pruning classes.

Pruning for health: When pruning any tree or shrub it is important to first start by pruning any diseased, damaged, and dead branches. Then prune out water sprouts and suckers that will take energy away from the main structure growth.

Pruning/training for structure: This is a very important step, and should start when the tree is young. Pruning/training for structure takes a little more imagination, and is best done by picturing what the tree should look like 5 years in the future and how to prune and train it to accomplish that goal.

OSU Pruning Basics

Some info on pruning mistakes

* Check out our page on Conifer Care for tips on how and when to prune conifers

Pest Management


Pests are often not as problematic on shade and ornamental tree as fruiting trees, but it is never a bad idea to regularly check the health of your tree, and if pests do arise, knowing a good pest management strategy can really help get you off to a good start.

Monitor: In late spring it is a good idea to monitor insect pest populations to get a understanding on when the best time to apply treatments are and how much pest management is actually needed. There is no need to treat for a problem that doesn’t exist yet, and can actually be detrimental to do so. Spraying pesticides, even low impact ones, can harm beneficials, like honey bees and predatory wasps, and should only be used when needed. Also, the more pests are exposed to a certain product, the more likely it is for them to build up a resistance, therefore it is one’s best interest to hold off on spraying until optimum conditions arise. Insect pests can be monitored by visually examining the trees on a regular basis and with pheromone and visual traps that are available at most farm and garden stores.

More information on pheromone traps

More on starting a pest management strategy

Attract Beneficials: Beneficial insects are insects that provide services to the grower that will aid in the health of their crops, such as pollination and pest control. The most common beneficial insects people think of are honey bees, lady beetles, and praying mantis, but there are many, many more, often looking like pests themselves, therefore it is important to identify insects before deciding they are pests and spraying. Beneficials can be bought and introduced to an area, but they can also be attracted to an area, and will be more likely to stay in that area if it provides them the correct habitat. Planting a diversity of specific plants, and providing access to water is the best way to create an attractive environment for beneficials.

More on attracting beneficial insects

More on releasing commonly sold beneficials

Low Impact and Dormant Sprays: When pest populations are too great for other approaches to be effective, and pesticides are needed, it is important to choose and use pesticides carefully. Pesticides can harm beneficial insects. If trees are properly planted, healthy, and monitored for pests, a low impact spray (one with little to no residual effect) should be sufficient. Commonly sold low impact sprays include, insecticidal soaps, horticulture oils, pyrethrins, organic spionsad, and neem. Rotating pesticides is crucial for reoccurring success and limiting resistance, it is recommended 3 different pesticides per season.

One of the most effective times to use pesticides is when the tree has gone into dormancy. Some effective dormant treatments include, lime sulfurs, horticulture oils, and copper fungicides.

More on dormant treatments

Even more on dormant treatments

OSU extension’s guide to managing diseases and pest in the home orchard

More Info


Check out OSU’s article Selecting, Planting, and Caring for a New Tree for more detailed information on general tree care

nursery plants online
nursery plants online