A Primer on Pruning

A Primer on Pruning

Pruning is a much needed yet often misunderstood practice. This is perfectly understandable as most people look at a tree and wonder which branches need to be cut, why they need to be cut, and what time of year is appropriate to do so. Confusion is understandable, but a better grasp on a few key concepts will clear everything up.

Structure

Red Maple
Red Maple structure IFAS Photo: Hassing, G.

Before you begin to look into anything else, it is important to understand the structure of a tree. For the purposes of pruning, we’ll focus on roots, and stems. The roots of a tree anchor it to the ground providing water and nutrition to the main stems of the tree. Roots and stems in any plant are a delicate balance. Cutting stem tissue will affect roots so don’t remove too much in a single session. A good rule of thumb is to not take more than 1/3 of the stem tissue present. The next concept is the natural shape of the tree you want to trim. Most have one dominant leader with supporting branches forming the canopy. In these cases, remove competing leaders to keep the canopy full and well-shaped. Other trees such as crape myrtle (Lagerstroemia indica) are multi-stemmed with 2-3 codominant leaders. Prune away any challengers to your main leaders while keeping the “vase” shape for which these trees are known. With this in mind, it’s time to decide which stems to remove.  

What to Cut

Safety and tree health are the focus as a homeowner decides which stems need pruning. When a branch is to be removed, make your cut It is important to keep the branch collar in mind when making your cuts. This collar is denoted as a ring of tissue at the connection of branch and trunk. Cut as closely as possible without disrupting this tissue. Any dead, diseased, and damaged branches are the first needing cut. They take resources from the healthy branches and are unsightly. Next, look for any crossing limbs. These scrape against one another as the wind blows and risk destroying bark tissue making the tree susceptible to disease. Focus next on structural issues or tree shape. Remove challenges to the leaders as outlined in the previous paragraph. Safety concerns will be your next focus. Look for bark inclusions which are weak connections indicated with a “V” shaped fork between limbs which may fail in high wind. If found, consult a certified arborist as pruning may not be your only option. Finally, eliminate lower limbs impeding walkways and any drooping from their own weight. This is also when species specific pruning is prudent to promote flowering or fruiting.  

Branch collar
Branch collar example IFAS photo: Gilman E., Bisson A.

When to Cut

Now that we know what to prune, when is it prudent to do so? This cycle will vary based on quality of stock from the nursery, age of the tree, growth rate, and how prone they are to decay. In Florida, this is on average every three years. Keep in mind the “May rule” when considering what time of year to prune. Any plant blooming prior to May should be pruned once flowering has ceased, but no later than July. Any plant blooming after May should be pruned around February or March at the latest.

Bark inclusions
Examples of bark inclusions IFAS Photo: Gilman, E., Bisson A.

Pruning is an important practice for keeping your trees healthy and ensuring safety. With some knowledge you’ll find it is not the mystery you may have thought it to be. For more information on pruning, please see these IFAS documents, or contact local extension agent for additional information on this and any topic regarding your gardens and more.

Winter is Tree Planting Time

Winter is Tree Planting Time

Red Maple
Red Maple structure IFAS Photo: Hassing, G.

January to February is the ideal time to plant trees.  During dormancy, all the energy in a tree is in the root system. They will establish very quickly.  In the spring, they will be ready to grow leaves. Planting and establishing trees is all about managing air and moisture in the soil. The exception is palms. They are not technically trees and should only be planted in the late spring and summer. Three of the most common causes of poor plant establishment or tree death are planting too deep, under watering, and over watering. If appropriate trees are planted at the right depth and they are irrigated properly, the trees will thrive for years to come. As simple as this sounds, problems often arise that lead to poor establishment or plant failure.

Following ten critical steps can ensure proper tree planting:

1. Look up for wires and lights. Make sure that the tree species’ mature size will not interfere with any utility lines.

2. Find the topmost root and treat root defects.   After removing the pot from the tree, remove all excess soil on the top of the root ball, until a root that is similar in diameter to the lower branches is located.  That is the topmost root.  Look for any roots that encircle the rootball, particularly close to the trunk.  Remove any roots that will strangle the trunk.  Cut all encircling roots at the point they turn to encourage root branching. Then, rough up or shave off all the roots on the perimeter of the rootball. If the tree is balled and burlapped, use a metal skewer to locate the depth of the topmost root.

Remove an inch or more for extremely rootbound trees.

3. Dig shallow and wide hole. Using the corrected rootball as a gauge, dig the hole slightly less shallow that the rootball.  Loosen the top six inches of soil around the entire rootball.

4. Carefully place tree in hole. Lower the tree into the hole slowly.

5. Position top root 1-2 inches above landscape soil. Make sure that the rootball is above the surrounding soil grade. If balled and burlapped, the nylon straps, metal pins, burlap on top of the rootball, and wire basket above the grade will need to be removed.

6. Straighten tree. Check the tree from two directions at 90% angles from each other.

7. Add and firm backfill soil. Tamp soil with fingers, not feet.  Do not stomp on the soil.  It will compact the soil and reduce the oxygen to the roots.

8. Add mulch.  Apply a 2–3-inch layer of natural mulch out to the perimeter of the trees branches, or beyond if possible.  However, there should be 1 inch or less mulch on top of the rootball.  Do not allow mulch to touch the trunk.

9. Stake and prune if needed.   If there is a strong steady wind, staking is necessary.  Otherwise, don’t stake. Make sure to do all structural pruning is done at planting time.  Establish a central leader and remove crossing branches. But do not remove the lower branches.  Just reduce the length.  The tree needs to bring food to the lower portion of the trunk to increase the diameter.

10. Water the tree. Don’t walk away until the tree has been watered.  Apply at least ½ gallon.  The tree will need to be watered twice a week for 20-30 weeks.  The larger the tree, the more water needed at each event.  However, if the water doesn’t perk in within a few minutes, reduce the amount being applied.  Overwatering can be as harmful as underwatering.

Is Your Tree a Champion?

Is Your Tree a Champion?

The Florida Forest Service implements the tree champion program in Florida. Credit: Florida Forest Service.

Humans love to measure and rank things. Whether it’s the tallest, the widest, or the most of something, we want to know about it, rank it, and, of course, brag about it if it’s ours. The biggest pumpkin, cheeseburger, truck tires, and so on. Gardeners and plant people are no exception. Actually, when you combine the pride of something you’ve grown with some type of measurement or rank of grandeur, it drives even more competition. Hence, fairs! So, it’s no surprise that there is an official rank of largest tree for each state. These large specimens are known as “Champion Trees” and every landowner I know of would love to have one on their property.

The idea of recognizing Champion Trees goes back nearly a century when the American Forestry Association, now known simply as American Forests, launched a campaign to engage the public in forestry activities. To tap into our desire to rank things and compete, the campaign encouraged a competition to find the largest specimens of selected trees. American Forests still maintains a registry of the national Champion Trees and their current goal of the program is to help people identify tree biodiversity and foster a desire to preserve and protect trees.

The Senator – no longer with us – was the state champion cypress. Credit: Creative Commons.

In Florida, the Division of Forestry (DOF), part of the Florida Department of Agriculture and Consumer Services (FDACS), maintains a statewide registry of these Champion Trees. According to FDACS’s Florida Champion Trees website, the largest native tree in the state is a bald cypress (Taxodium distichum) with a trunk measuring 537 inches in circumference (nearly 15 feet wide), stands 101 feet tall, and has a crown spread of 49 feet. That’s a big ol’ cypress tree! Just in case you were wondering, the smallest Champion Tree is a corkwood (Leitneria floridana) with a trunk measuring nine inches in circumference (almost three feet in diameter), 17 feet tall, and a crown spread of eight feet. That is a big ol’ corkwood!

Corkwood (Leitneria floridana), a native wetland tree, is the smallest state champion. Credit: Creative Commons.

Now comes the exciting part. The Florida Champion Trees website (https://www.fdacs.gov/Forest-Wildfire/Our-Forests/Florida-Champion-Trees) has the entire list of trees for you to peruse and includes a list of trees that are yet to have a champion specimen designated. There is a nomination form that, when submitted, will prompt a visit by a County Forester with DOF who will confirm the tree’s measurements. If all checks out, your tree could be a champion!

Planting Depth Problems Continue

Planting Depth Problems Continue

Several times each month I am diagnosing shrub and tree problems in Escambia County that are related to the same issue, improper planting.  Symptoms of this problem can be slow growth, leaf browning, and dieback.  Sometimes under stressful weather conditions like drought, plants completely die. 

The trunk was covered with several inches of soil. Photo by Beth Bolles, UF IFAS Extension Escambia County.
Shrub stems should never be below the soil level. Photo by Beth Bolles, UF IFAS Extension Escambia County.

This is a difficult sight for homeowners who have invested time and money in a tree or shrub to enhance the landscape.  In some cases, the planting issues can be fixed but there are other times when a new plant will need to be installed. 

The good news for homeowners is that this is a completely preventable issue.  The University of Florida has excellent publications with photos about installing and caring for trees and shrubs.  My Panhandle colleagues and I have also shared numerous articles and videos on proper plant installation. 

Care must be taken during installation to set your plant at the correct depth.  Even if a landscaper or nursery is installing the plant for you, check their work.  Make sure the rootball is cut or sliced, it is not set below grade, that any straps holding the rootball are cut after it is set, and proper backfilling occurs without soil over the top of the rootball. 

You don’t want to find out later in the season or even year’s later that your plant declined just because of planting problems. 

Select and Plant Trees for Florida’s High Wind Climate

Select and Plant Trees for Florida’s High Wind Climate

Many future problems can be avoided by paying attention to tree selection, planting and maintenance in Florida’s high wind climate. We may think of tropical storms causing tree damage but our typical summer thunderstorms can produce winds in excess of 50 miles per hour with downbursts reaching over 100 mph. 

There is no way to protect trees from all storm damage. Trees are not adapted to worst-case storms, such as Hurricanes Michael or Ian, only to our average wind climate.

It’s wise to take time to select and correctly plant the right trees for North Florida.

Past hurricanes have taught us that large growing trees planted too close to curbs, sidewalks or buildings blow over easily because they don’t have adequate room to develop a sound root system. It’s best to either plant these trees farther away, plant trees that may stay small, or increase the size of space allocated for tree root growth.

Research and storms have taught us that tree roots need large soil spaces for strong, stable growth. The more rooting space trees have, the less likely they are to fail. Strong root growth is essential for tree stability and health. Large maturing trees need at least 30 feet by 30 feet (900 ft. sq.) of rooting space. Many construction practices such as paving over roots, raising and lowering soil grade, and soil compaction from equipment result in root injury for existing trees, making them less durable and less stable.

Magnolia Tree in the Landscape. Photo courtesy Stephen Greer

Studies have also shown that trees growing in groups better survive high winds compared to individual trees. A group was defined as five or more trees growing within ten feet of another tree, but not in a row.

A short list of large maturing, storm resistant trees to consider include live oak, sand live oak, bald cypress, pond cypress, black gum and magnolia.

Do some homework and take a look at tree species that have done well in your area. If you don’t want or need a large tree in your yard, there are many small and medium sized wind-resistant trees from which to choose, like Crape Myrtle and Vitex. Many palms are wind resistant too, particularly the cabbage palm.

Having success with trees in the landscape involves starting with healthy, well-developed trees. Plant the right tree in the right place. Follow good planting procedures, including not planting trees too deep and providing adequate root space to allow for strong, healthy root growth. Practice correct maintenance techniques, which includes learning how to prune to produce a structurally sound tree. Finally, consider if it is time to be proactive and have large over-mature, declining trees removed and replaced before the next storm.

The following UF/IFAS Extension link, Trees and Hurricanes, includes the most current recommendations on tree selection, planting and pruning. https://hort.ifas.ufl.edu/treesandhurricanes/wind_and_trees.shtml