Misconceptions about Planting and Caring for Plants

We are living in a time of change. Even the old established landscape practices that we were taught and have accepted as fact are changing. Unfortunately, many of these landscape practices were never researched to determine if they were valid. They were simply accepted as the right thing to do because they appeared in gardening books and were recommended by gardening experts.

Today, research has shown that many of these tried and tested landscape practices are of no value and in some cases may be harmful to plants. The practice of applying wound dressings and pruning paints to pruning cuts is a good example of a practice that provides no benefit to a plant. Wound dressings don't prevent wood decay behind a pruning cut. When exposed to the sun, these protective coatings often crack, allowing moisture to enter and accumulate in pockets between the wood and the wound covering. This situation may be more inviting to wood rotting organisms than one with no wound cover.

In the past, it was a standard practice to prune tree branches flush with the trunk. This practice injures the trunk and shortens the life of trees. Pruning cuts should be made outside branch collars that are located at the base of branches. These collars are easily seen as swellings where branches meet the trunk.

Pruning transplanted trees and shrubs to compensate for loss of a portion of the root system is another practice which has proven to be unnecessary and in some cases detrimental. Loss of foliage through pruning at the time of transplanting decreases the ability of the plant to synthesize the food and growth substances necessary to produce new roots.

The practice of collecting grass clippings is believed to prevent the formation of a thatch layer in lawns. This is simply not true. Grass clippings decompose rapidly and do not contribute to the formation of a thatch layer. Since grass clippings contain about 4 percent nitrogen, returning them can actually improve the quality of a lawn.

A common practice when planting trees and shrubs involves adding an organic material such as peat to the soil used to fill around the root ball. However, a significant amount of research provides no evidence that this practice is beneficial. Plants will survive and grow as well by using the unamended soil removed from the planting hole to fill around the root ball at planting.

These changes occurred because researchers dared to question landscape practices which have been passed from one generation to the next without critical evaluation. I am sure that as scientists continue their search for better ways of planting and maintaining landscape plants, more of these old landscape practices will be found to be of little value.