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Master Gardener Scoop: February 15, 2017

How Accurate Are Gardening Myths?

By Will Summers and Linda Summers, Master Gardeners

In February gardeners look forward to the next gardening season.  Take a time-out to reflect on some concepts, and perhaps misconceptions, of gardening.  Many of these relate to planting trees and shrubs but may also pertain to all gardening.  Trees and shrubs are likely the most expensive and enduring garden plantings.  Most of these mistakes involve killing your plant with kindness.

In gardening, as in many things:  “Keep It Simple”.  Here are some gardening issues that reappear to prevent gardens and landscape plantings from being wholly successful.

I should fertilize newly planted trees, shrubs, flowers and garden plants to make them grow better. – No, fertilizer will cause them to acquire moisture stress.  Since most commercial fertilizers are salts, the salt upsets the osmotic potential in tree roots, which inhibits their ability to uptake water.  Secondly, the salt-like substances can actually burn roots.

I can amend poor soil by adding potting soil, compost or peat when planting new trees and shrubs. – No, add only the native soil.  Creating an artificial environment next to newly establishing roots will create a “flower-pot” situation that will inhibit root extension into the surrounding soil.  My personal trick is to add some soil collected from an established forest understory that contains native soil organisms, fungi, molds and their microrhizae to inoculate the planting hole.

My pruning helps newly planted trees and shrubs. – Wrong again, let the tree decide what it needs and what it does not.  Only prune back dead, diseased or damaged plant parts.  Make sure the plant has consistent watering to prevent moisture stress.

I brace, guy, stake and support all newly planted trees and shrubs. –  This is wrong in so many ways.  Guying a properly planted tree is unnecessary in almost all cases.  In commercial plantings, it adds an extra $50 or more to the cost of the tree.  In many cases, guys and supports are left in place, untouched for years until the supports grow into the plant tissue and girdle the stem.  Trees, like people, grow weak with unnecessary support and in trees at least, they become susceptible to wind breakage.

The deeper the planting hole the better. – No, dig planting holes wider to loosen the soil, but always plant the tree or shrub at the original soil level of the pot, container or soil root ball.  In a container grown plant, check to see if the “root-crown” (the point where the vertical stem(s) joins the first roots) is at the container soil surface. You should notice a flare at the base of the tree. If not, we advise you to raise the planting height so that the root crown slightly projects through the top of the finished soil surface.

I can improve heavy clay soil by adding sand to improve drainage. – Wrong again.  Although this may sound logical, we tried this and it actually turns clay into something as hard as cement.  Instead, add compost, peat moss or other organic matter to loosen clay soils.

I should paint all newly pruned branches with “tree-wound-heal” material. – Materials sold as tree woun d are intended to prevent entry of damaging insects, rot and diseases.  However, these materials may be initially damaging or caustic to sensitive plant tissue or will cover and protect these organisms.  Consider limiting your heavy pruning to the cold winter months when these plants are in their deepest dormancy, when insects are fewest and there are less abundant disease organisms.

You have to be a Master Gardener to have a good garden. – No, some of the best gardeners we have ever known are self-taught by experience.  True, we learn by mistakes, but some of the best gardens may be grown by beginners.  Therefore, remember:  Gardening is for people who like to garden and certainly not only for experts.  You may become an expert yourself; however, the more you garden.

Please direct your gardening questions to your local University of Illinois Master Gardener, your local Extension Service office, or visit your local library.

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