When it comes to athletic fields, the focus is generally on the playing surface – first and foremost. But at many sites, other plants are valuable for participants and spectators alike. These include trees, shrubs and other ornamentals, often strategically located for the benefits of shade and aesthetics. In order to keep them in good health and functioning well, best management practices should be devised and implemented, just as is the case for the turfgrass plants.
Right plant, right place
The tried and true guideline of right plant, right place (RPRP) is of utmost importance at an athletic facility. Made up of many factors, this approach helps steer the plant selection process in a successful direction.
The first consideration is location. At first glance, it might appear to be obvious; just put trees and shrubs anywhere but in the field of play. But unlike turfgrass in full sunshine, where uniform mowing, pest control and other maintenance procedures are followed, the concept of RPRP must be followed in terms of plant health, good siting and functional benefit.
Foundationally, it’s important to set and prioritize goals for the plants themselves. A typical goal would include creating a shaded location for team gatherings that would reduce heat/stress on players during practices and games. Another would be privacy from adjacent properties. In some situations, it’s also important to separate one field from another. And, naturally, another goal is to improve the appearance of the facility. Not all of these are important at every site, yet all should be considered when determining the best location for trees and shrubs.
Other important RPRP considerations include selecting plants based on sun and shade conditions. Certainly, the eventual height and width should be factored into the planting decision, as well as the need for inputs. Evaluating potential budget allowance often helps with this process.
Should trees and shrubs at an athletic field be fertilized? If so, when? The answers to these questions depend on several factors. A few guidelines will help determine the need for fertilization of most woody plants. If they’re in the midst of – or adjacent to – the turf, they share the same root zone. They’re also likely to have absorbed nutrients slowly and steadily over the growing season, beginning in spring as well as over the summer.
Second, consider that the vast majority of trees and shrubs require about a fourth to a third of the nutrient levels that turfgrass does. If their roots are directly under the roots of the turf, it’s likely that they already receive adequate amounts for the growing season.
Another important consideration is if they show deficiency symptoms, which include the following:
- Yellow leaves
- Yellow leaves with green veins
- Stunted growth
- A slow-down in the rate of growth over the past few years
- A thin canopy
- Dark blotches on stems
- Fruits or leaves of a color other than green.
Soil and tissue testing can be helpful in determining if a lack of fertility is the cause. Certain ornamentals such as azaleas, rhododendrons and holly may be problematic under alkaline soil conditions in that they require low pH levels to thrive.
Trees, shrubs and other ornamentals that aren’t sharing the same space as regularly fertilized turfgrass may require annual or seasonal fertilization, depending on the region of the country and species of plant.
Overall, the separation of trees and turf is highly desirable as the individual needs of fertility and irrigation can be provided for both (mower and string trimmer damage can be avoided as well).
The need for irrigation is also dependent on location. Find out the irrigation needs of the trees in the complex and keep in mind that most trees prefer to have moist, not soggy or dry, roots. This is usually a good place to start, however, a little investigation is helpful in tweaking the scheduled applications of water.
Again, if they’re next to the field, at least half their roots are probably growing in the same soil as the turf and are likely to receive some moisture by default. Deep probing with a piece of rebar is helpful in determining the need for irrigation. Supplemental irrigation water can be applied with a dedicated zone within the existing sprinkler system, or with drip equipment, which is appropriate when establishing new trees. Keeping individual needs in mind is a key to success with tree irrigation.
Unfortunately, trees are not without flaws. With the mindset of considering targets (people/property of value), it’s crucial to consider what a tree or tree part could fall on. This slice of arboriculture is called tree hazard awareness and tree risk assessment, made up of existing or developing defects and valuable targets. Defects become important when spectators or athletes spend time under or near trees while focused on the game or practice.
Fortunately, with just a little investigation, possible defects like cracks, codominant leaders, decay, basal/root plate issues, stem girdling roots and leaning can be identified.
It’s wise to include tree inspection in the scouting routine for the field, looking for obvious insect or disease problems as well as flaws. Then, confirm suspected problems with an International Society of Arboriculture-certified arborist. In consultation with the arborist, consider targets when defects are identified such as bleachers, parked cars, bathrooms, dugouts, etc.
In a nutshell, pruning is best thought of as removing unnecessary or undesirable growth. The need for pruning could follow with removing defects as described above, storm-damaged stems or brushy growth that gets in the way of mowing and other turf maintenance. As determined necessary in consultation with an arborist, look for rubbing branches, low-hanging limbs, closely parallel branches and pests such as cankers that should be removed.
For the most part, pruning should be done by a certified arborist. A possible exception would be a small ornamental, such as a crabapple, that can be easily reached from the ground. You might hear of a desire to apply a pruning paint over fresh cuts. Research at many land-grant universities and arboretums has demonstrated that wound dressings actually increase the potential for decay and other problems. Thus, it’s best to leave recently pruned trees to cover wounds on their own.
The above factors go a long way toward providing for the needs of trees in the athletic field landscape. A few other factors are important as well:
- Try mulching to avoid string trimmer and mower damage to a tree’s trunk. Not only will a 2- to 3-inch layer of wood chips, pine straw or ground corncobs retain moisture and suppress weed growth, it will also help guide 15-year-old mower operators around the tree, rather than into or through it. Once this type of damage is done to a young tree, it’s difficult for it to recover.
- Plant on gentle slopes rather than severe ones. It’s just hard to obtain appropriate water and nutrient infiltration on a slope. When slopes are severe or hard to mow, it’s best to plant ground covers such as low-grow junipers, sedums, rosemary, lily turf, honeysuckle, lamium, euonymous, periwinkle or ice plant.
- Separate turf and ornamentals – they have different needs. Turf must be mowed; trees should be as far away from the mower as possible. Trees and shrubs generally need far less water and nutrients than turf does. Sports turf is made for human feet to run on. This isn’t so for trees and shrubs. Separate, yet adjacent planting, is suitable for athletic facilities to yield the benefits of both.
- Routine scouting and monitoring is the best way to avoid insect and disease injury. Finding pests in turf is a looking-down activity. Since tree inspection involves looking at leaves and stems that are 10 to 70 feet in the air, a pair of binoculars is handy to find what might be lurking over your head.