Don’t mourn – fertilize!

200338272-001Some folks see the death of any plant as a ­funereal experience, lamenting the loss of a plant and the potential end of the world. Some of us say “Ah, such is life.” and then “Wow! I have room to put something else in.”

That being said, tree death for the most part is something to mourn. Big old shade trees have seen many moons, many rainbows, and many snow storms. They can mark the birth of a child or the death of a great grandparent. But for many ­homeowners, they are just there, ­leafing out in the spring as the days get ­longer and shedding their leaves as the days get shorter.

To that end, now is the time to help those trees, though it seems backwards since the tree is going dormant for the year.

Fertilizing is key! While Mother Nature provides some in the form of decaying leaves and squirrels who didn’t quite make it jumping from tree to tree in the forests, it’s often not enough in the home landscape.

Most homeowners don’t recycle the leaves under the trees. Sometimes there are too many leaves to mulch with the mower and let filter between the grass blades, which instead build up on top and smother the grass. So we rake and/or blow the leaves where they are disposed of in some method.

And if we have turfgrass around the trees, the grass roots will grab most of the nutrients before the trees.

That’s where fertilizer comes in.

If you fertilize the tree at the dripline, not at the trunk where it provides little benefit, the tree’s roots will absorb the nitrogen, phosphorus and potassium over the remainder of the year and next spring, and provide a boost to the tree. As long as the ground isn’t frozen, the roots will ­continue to absorb some of the nutrients.

It’s important the fertilizer is around the tree’s roots and not the grasses. Just scattering some extra fertilizer around the tree’s dripline, or outer branches, will probably result in a thick green lawn in that area. The fertilizer has to get to the tree’s roots.

Root feeders and root probes are one method, though probably not the most efficient. You stick a fer­tilizer tablet into a probe that’s pushed into the ground 12 to 18 inches with a hose attached. The water slowly ­dissolves the nutrients which move into the soil.

Tree spikes are also available, but dollar for dollar, are much more expensive than what you can do with a three-quarter inch piece of rebar, three feet long, and a bag of fertilizer.

David Robson is Extension Specialist, Pesticide Safety for the University of Illinois.
David Robson is Extension Specialist, Pesticide Safety for the University of Illinois.

Take the metal rod and tap it into the ground 12 to 18 inches. Pull it out, and go around the dripline of the tree another three feet. Tap the bar into the ground, pull it out and move another three feet. Once you’ve made a circle around the tree, step roughly three feet out, and make another circle of holes, and then three feet toward the tree from the dripline and make a third circle of holes three feet apart.

Next, fill each hole with regular garden fertilizer such as a 10-10-10, 12-12-12 or something similar. Pour no more than six ounces of fer­tilizer in the holes. Then turn on the ­sprinkler to wet the soil, the holes and fertilizer.

You don’t need to fertilize every year, but plan on it once every three to four years, especially if you have a manicured yard.