My favorite part of spring is when the grey, baren branches of deciduous trees starts to come alive with new light green foliage

It is also the time when folks start to look at their trees with a new interest, seeing things they had not noticed in the past. As this curiosity about landscape trees reaches a peak soon, I figured it might be a good time to set the record straight on some misperceptions about trees that have been around a long time.

The first one is a biggie. Sometimes during presentations to adults, I ask them to describe to me what a trees root system looks like. Many of them describe something that looks akin to a carrot with little roots branching off to either side.

This leads us to our first myth, that “trees have tap roots”

Many are surprised to learn that tap roots are an exception, and not the rule. It is true that as tree seedling develops, a tap root forms. However as it gets 10-12 inches long, it soon reaches depths where soil oxygen is limited and it stops growing. Lateral roots then emerge and start to spread horizontally typically reaching depths of only 18-20 inches. These lateral roots then spread out 2- 3 times the width of the branches if there is room. Many times, in urban areas there are lots of obstructions to root spread such as buildings, sidewalks and streets. This is why it is important to make sure that the tree you plant matches the space you want it to grow in.

When researching how to plant a tree we have often heard that we should “plant the tree at the depth it is growing in the container”

If we follow this myth, we are almost always planting the tree too deep. Typically, trees planted to deep have a hard time thriving. Instead, trees should be planted where the top most roots that emanate from the trunk should be placed slightly above the ground level. A forester friend of mine came up with a saying that I will always remember. It went “plant it high and it wont die. Plant it low and it sure wont grow”. The reason you should plant a tree higher is that the growing medium in the container will start to decompose and the tree will start settling. If we plant it a few inches higher, it will eventually settle at the proper depth.

After we plant the new tree slightly higher, we need to water it well until it becomes established

Hence our third misperception that “turf irrigation is sufficient to water a new tree”. A newly planted tree needs a lot more water directed onto the rootball than an irrigation sprinkler can provide. They need a source of water that places water directly onto the rootball either by hand watering, or an emitter from the irrigation system called a bubbler. At each watering a tree should get 2-3 gallons for every inch in trunk diameter. For instance, a 2 inch diameter tree needs 4-6 gallons at each watering. This should be done every day for one month, every other day for 3 months, and then every week until it is established. Once it is established the tree can often make it on its own. For a great publication on planting and establishing trees, go to: https://hort.ifas.ufl.edu/woody/documents/EP314.pdf.

Finally, we come to our last misperception

I hear this one often. It is that “thinning out the canopy so that wind blows through it makes a tree more wind resistant”. After the numerous tropical storms that hit Florida in 2004, a lot of research went into how to prune trees to make them more wind resistant. Researchers even blew trees around with large fans https://hort.ifas.ufl.edu/woody/blowvideos.shtml. What they found was that thinning out the interior of the canopy made the trees much LESS wind tolerant. They even gave this type of pruning a name. It is called lions-tailing and gets this name by the look of overly thinned tree canopies with lots of growth concentrated at the ends of the branch looking like the tail of a lion.

When the interior of tree canopies get thinned out, the weight of the branch is now concentrated towards the outside of the canopy. This puts more strain on the branch. Add something like wind, and it often results in broken and damaged limbs. The most wind tolerant trees are the ones that are maintained by pruning cuts called reduction cuts that appropriately shorten the length of branches and leaving interior branches at the same time.

For more information on proper tree pruning, go to: https://hort.ifas.ufl.edu/woody/documents/ch_13_mw06.pdf

As we notice our trees leafing out this spring and gain a new appreciation of their contributions to our landscape, try and find the most up to date information on how to take care of them. A great place to start is at the University of Florida/ IFAS Extension search page. You can search for lots of great information on trees, plants, and even vegetables at https://edis.ifas.ufl.edu/ .

Article written by Larry Figart, Urban Forestry Agent, Program Coordinator, April 2023

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