Each year, I like to encourage people to consider planting a tree or shrub around Arbor Day (the last Friday of April – this year, April 25). We’ll get to some planting tips toward the end of the article, but first, what is Arbor Day?
Due to the Latin origin of the word “arbor,” “Arbor Day” could be translated to “Tree Day.”
Arbor Day, a celebration encouraging tree planting and appreciation, originated in Nebraska in 1872, spearheaded by J. Sterling Morton, who proposed a tree-planting holiday to address the lack of trees in the region.
Indiana first observed Arbor Day in April 1884, but it wasn’t until 1896 that it became an annual event. The official date was changed several times, starting with a specific date in April. In 1929, it changed to the second Friday in April. In 1991, the date was changed to the last Friday in April to avoid conflicts with school spring vacations and Good Friday.
Arbor Day in Indiana coincides with National Arbor Day. In 1970, Arbor Day became recognized nationwide through the efforts of President Richard Nixon.
In practical terms, Arbor Day is the last Friday in April because that’s a great time to plant a tree!
Before choosing just any old tree, you should do some research on what tree may best serve your purpose in the specific location in your landscape. I won’t cover this subject in detail today, but you might refer to an article I published last year at https://extension.purdue.edu/news/county/whitley/2024/04/arbor-day-choosing-the-right-tree.html.
For planting tips, I’ll be excerpting high points of Purdue Extension publication FNR-433-W, “Tree Installation: Process and Practices,” authored by Lindsey Purcell, Purdue Extension urban forestry specialist (retired).
In the publication, Purcell outlined a 12-step process for proper tree installation that I will summarize, plus add a few clarifying editorial comments:
1) Select the appropriate tree for the location. (Refer to the 2024 article mentioned above).
2) Dig the planting pit 1–1½ times as wide as the root system, and only as deep as the main order root system. Box or shave the perimeter of container plants to prevent circling roots. Find the root flare and make sure it is not below the soil line at final grade establishment. (If you have heavy clay soils, it may be prudent to dig a wider hole – up to 2-3 times the width of the root system. See # 5 for more on the depth of the hole.)
3) Provide proper drainage for tree survival. (Select the appropriate tree for the drainage type.)
4) Prune the tree to remove and prevent problems. Eliminate co-dominant stems to establish one central leader or main trunk. (Concentrate mainly on dead, broken, and damaged branches for now – very minimal, and only what’s necessary. See Purdue Extension publications FNR-506-W and HO-4-W for pruning tips in the early years of a tree’s life.)
5) Set the tree in the hole with the root collar even or slightly above existing grade. Also, do not pick the tree up by the trunk. Always handle by the container or root ball. (The root collar is also known as the root flare, and this should be visible above the finished soil grade. It is just above the first main root.)
6) Remove all foreign materials from the root ball. If planting a balled and burlap tree with bio-degradable burlap, remove the upper ½ to 1/3 of the handling materials.
7) Gently backfill the hole with native soil. Soil amendments and fertilizers are not necessary. Construct a small earth rim around the planting pit to help hold water. (Put the soil that came out right back in without amendments.)
8) Stake the tree, if necessary. (Use only in windy or challenging areas to avoid tree failure. Stakes or guys are used for the first year or two only.)
9) Mulch the planting area. (Apply 2-3 inches over the planting area to at least the dripline or tips of branches, but none at the trunk. An air gap of 2-3 inches around the trunk should be maintained.)
10) Water the tree, but don’t drown it. An infrequent, thorough soaking is much better than light, frequent watering. About 1” per week from rain or watering is preferred.
11) Protect the tree from animals and humans. (Use a tree guard at the base, and easy with that string trimmer!)
12) Avoid fertilization during the first growing season. (Water is most important. Drought-stressed plants should never be fertilized.)
Two of the most common mistakes that homeowners make are planting the tree too deeply (#2, #5 above), and mounding a “volcano” of mulch around the tree (#9).
Find additional information from resources at Purdue Extension’s Education Store, https://edustore.purdue.edu/. For tree planting tips, see “Tree Installation: Process and Practices,” FNR-433-W. For a helpful video, find “Tree Planting Part 2: Planting a Tree,” FNR-540-WV.