Celebrate Arbor Day – plant a tree

Arbor Day is the last Friday in April in Indiana; this year it is April 27. This date is strategically chosen to be right in the middle of one the best time periods all year to plant a tree in Indiana. Fall is also a good time. So, if you have been thinking about adding a tree or two to your home landscape, late April is a great time to do it! A Purdue expert offers some tips for you to increase your chances of success.

“Before planting your tree, consider the tree’s ‘fullgrown’ size,” wrote Lindsay Purcell, Purdue urban forestry specialist. “When the tree nears maturity, will it be too close to your house or other structures?” Purcell added that when selecting trees for energy efficiency, don’t plant evergreen trees near the house on southern exposures. Trees may provide some shade and screening, but will also block out the warming effects of the sun during winter months.

When considering placement of larger deciduous trees, Purcell said that a good rule of thumb is to plant the tree at least 20 feet from the house. For larger shade trees, you may need to plant as far as 40 feet from the house to ensure room for growth.

It’s a good idea to consider the site characteristics of your own landscape, specifically in the location in which you want to plant a tree. This is important because the site may favor or eliminate certain species of trees based on what conditions the trees typically thrive in, or conversely, what conditions they may be challenged in.

Consider topography, drainage, soil type, whether it’s in full sun or partial shade, and proximity to power lines and structures. For example, in areas that collect and hold water (a low spot in your lawn), a River Birch would be well-suited, but most pines or spruces would probably struggle to thrive. It’s important to do some research on characteristics of potential trees to match the right tree for the right place.

Of course, it’s also important to plant the tree correctly. Two common mistakes that homeowners make is planting the tree too deeply, and mounding a “volcano” of mulch around the tree. The rule of thumb on depth is that the root flare, or fattened area of trunk just above the first main root, should be visible above the finished soil grade. Note that when purchasing balled-and-burlapped trees for planting, the top of the root ball may not be the location of the desired finished soil grade – the root flare may be farther down. Two-three inches of mulch should be added around the tree to help reduce water loss in the root zone and suppress weeds, but none should be in contact with the trunk.

“Young trees need protection against animals, frost cracks, sunscald, lawn mowers, and string trimmers.” Purcell said. “Mice and rabbits frequently girdle small trees by chewing away the bark.” Since the tissues that transport nutrients in the tree are located just under the bark layer, a girdled tree will die. Without using caution, operators of string trimmers can get too close to the tree and cut into this critical layer of tissues. “Plastic or vinyl guards are an inexpensive and easy control method,” said Purcell.

Purcell outlined a 12-step process for tree installation in Purdue Extension publication FNR-433-W, “Tree Installation: Process and Practices,” available free at Purdue’s Education Store, mdc.itap.purdue.edu. Here are the main points of each step, plus a few clarifying editorial comments:

1) Select the appropriate tree for the location.

2) Dig the planting pit 1–1.5 times as wide as the root system. (…and only as deep as it allows the root flare to be visible above finished soil grade).

3) Provide proper drainage for tree survival. (Select tree for drainage type).

4) Prune the tree to remove and prevent problems. (Concentrate on dead, broken, and damaged branches for now).

5) Set the tree in the hole with the root collar even or slightly above existing grade. (Root collar is the above described root flare. Also, do not pick the tree up by the trunk. Always handle by the container or root ball.)

6) Remove all foreign materials from the root ball. (If planting a balled and burlap tree with bio-degradable burlap, removal of only the upper half to a third of the handling materials is all that is needed.)

7) Gently back fill the hole with native soil. (Soil amendments and fertilizers are not necessary – in other words, put back exactly what you took out).

8) Stake the tree, if necessary. (Stakes and guys for first year only).

9) Mulch the planting area. (Remember, 2-3 inches, but none at trunk).

10) Water the tree, but don’t drown it. (About 1” per week from rain or watering is preferred).

11) Protect the tree from animals and humans. (Use a tree guard at base, and easy with that string trimmer!)

12) Avoid fertilization during the first growing season. (…especially for drought-stressed plants).

Find more details in Purcell’s aforementioned publication, and in Purdue Extension publication HO-100-W, Planting and Transplanting Landscape Trees and Shrubs, both available at the Education Store.

John Woodmansee is an extension educator in Whitley and Noble counties.

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