Webster’s Dictionary defines stupid as slow of mind: obtuse, and given to unintelligent decisions or acts. Well, I am stupid. Who in their right mind would have a garden center filled to the brim with landscape plants in May in Wyoming with snow and cold in the forecast? Or as Forest Gump would say “stupid is as stupid does”. So now that you know I’m stupid, let’s chat about young tree care.
Last Sunday’s gardening column was about planting trees. To recap, I asked gardeners to call One Call of Wyoming 811 two business days before planting to locate underground utilities, and to plant only to the depth at which the tree was growing in the container, making the whole twice as wide as the root ball and to cut circling roots.
But that’s only the first step, albeit a critical step to caring for your trees of which many of them will live longer than you.
Inoculate your planting site with beneficial fungi called mycorrhizae. All living soils have mycorrhizae but those in Wyoming soils may not be suitable for maples or oaks, for example.
These commercially available fungi form a symbiotic relationship with the tree’s root system. Basically they help the tree by enhancing the tree’s ability to extract water and minerals in the soil for basic tree metabolism. In return the tree provides food in the form of glucose to the fungi. The net effect is that mycorrhizae make the trees stronger and in Wyoming that’s a good thing.
Keep grass and other vegetation three or more feet away from young trees. Grass roots are very competitive with the roots of young trees, so much so that they can literally deprive the tree of water and nutrients making the tree weak and in some cases killing your trees. In lieu of vegetation around your tree use wood mulch two to three inches deep. I want to have the tree in its young days to have the competitive advantage of no below ground competition.
About fertilizing your young trees I could literally write a PhD dissertation. Nobody wants to wade through that much gumbo, so I’ll keep it brief. Fertilize your trees during leaf emergence and early tree growth—which means now through June.
I prefer a soil application of fertilizer. Apply the fertilizer broadly over the surface of the soil, do not use fertilizer tablets. Fertilizer tablets are concentrated meaning they can become toxic to the tree’s roots. A classic study looked at fertilizer tablets and the response of tree roots to the fertilizer.
The study’s author followed the fertilizer’s labeled instructions at time of planting. A year after the trees were planted with the tablets in place, he dug the trees up and observed in every case the roots grew away from the fertilizer; in effect it was too much of a good thing.
This may sound counter-intuitive, but in dry windy Wyoming we kill more trees by drowning them with too much water than not enough water. Trees need water below ground, but they also need oxygen. When a gardener irrigates too frequently, the water displaces the oxygen, in effect causing drowning.
I can’t tell you how much water to apply or how often but I can tell you a small investment of a soil moisture meter can take the guess work out of irrigating. Most have a scale of 1 to 4, with 1 being too dry and 4 being wet. With a reading of ‘1’, stop whatever you are doing and water your trees. Conversely, a ‘4’ means don’t water. I train all of my staff with a moisture meter.
So there you have it, a guide to young tree care from an obtuse garden center owner!
Originally published in the Casper Star-Tribune, May 24, 2015