Of all the peculiar methods and practices that we use to protect and maintain our beloved plants at the Indianapolis Museum of Art, the use of tree injections may be one of the strangest to observe. Imagine a couple of garden staff members drilling holes and inserting tubes into trees, pumping bright green liquid right into the trunks. A sight such as this might seem like more harm than good to the tree. However, the use of injections is the reason for the continuous health of some of our trees here at the IMA. The need for tree injections varies from tree to tree. The reasons can range from eradicating invasive pests to preventing killer diseases.
For example, the maples on the Dudley V. and Mary Louise Sutphin Mall of the IMA provide a lovely sidewalk border perfect for strolling in the shade of the trees. However, the soil that these trees are planted in doesn’t provide the best nutrients. Iron is a very important element to plant health and it plays a large role in the successful conduction of photosynthesis. The photosynthetic process is fundamentally the lifeblood of most plants.
Unfortunately, the soil on the lawn does not contain much iron and the trees experience deficiencies. These deficiencies cause a yellowing of the leaves and a condition called iron chlorosis. Thankfully, we have a solution we can inject into the trees that contains iron and other important elements to keep the trees happy and healthy.
Tree injection begins with a measurement of the trees’ diameter and circumference to determine how much solution needs to be injected. After that, the solution is poured into what’s called a “Tree I.V.,” and the injection site is drilled into the trunk. The small yellow “plugs” provide a place for the needle to stick and additionally protect the wound after injection is complete.
The trees simply grow new bark over the plugs as time goes on. When it comes to our maples, the iron-containing solution will travel from the injection site in the trunk, through the vascular system of the tree, all the way up to the leaves. Once the whole process is complete, we can watch as the solution provides the means for increased photosynthesis. This will allow the healthy green color to return to the leaves and improve their overall state. So the next time that you see a staff member drilling holes in a tree, know that they are (probably) not crazy, but are just continuing to keep the IMA beautiful.