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Too mulch of a good thing?
Let the principle of balance guide your approach
to managing healthy ornamentals.
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Inspect the course for trees with co-dominant leaders and/or decay. Tend to trees like this one right away if it’s in a high-traffic location. Photos by John Fech |
The more, the better, right? In most cases, human nature being as it is, if we find something that works well, we apply more of it or use it more often. This, however, usually isn’t a good plan.
When it comes to the care of ornamentals on the golf course, balance is important. Other aspects of our lives set the tone for this approach and are filled with examples of the need for balance, such as limiting snacks to once or twice a week and eating plenty of vegetables.
Just as there are rules for healthy eating, there are guiding principles for the five basic areas of plant care.
Mulch
Guiding principle: Replicate Mother Natur
In most forest settings, you’ll find leaf litter or “arbor droppings” on the forest floor — bits and pieces of bark, twigs, faded flowers, fruits and leaves. They are usually piled up to a depth of about 3 to 4 inches.
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Avoid mulch “volcanoes,” with mulch dumped all the way up to the base of the tree. |
The next time you need a diversion or feel the need for a road trip, drive to a nearby forest preserve or nature center and kick your way through the trees. As you walk, reach down and examine what has fallen to the ground. Directly underneath the surface droppings, you’ll find that some of the litter is decomposing into soil, and under that, you’ll find black gold — natural compost. The decomposition process is how nutrients are cycled back to the tree, picked up by the roots.
This process emphasizes the need for areas around each tree that will allow for the natural recycling of leaves and other arbor droppings. Trees planted in pits or with lots of concrete around them, such as those placed near or in parking lots and patios, have compromised root systems and will develop poorly, due in part to the lack of nutrient recycling.
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Place mulch 2 inches away from the trunk and extend it as far away from the tree as play will allow. |
But applying mulch indiscriminately isn’t a good idea, either. When mulching around trees, consider what’s best for the plant as well as what is practical for the course. Start by placing mulch 2 inches away from the tree trunk and extend it as far away from the tree as golf play will allow. Avoid mulch volcanoes — those obnoxious-looking loads of mulch dumped at the base of trees. The bole (base) of a tree should remain open to the air; otherwise a more favorable environment for diseases such as Armillaria root rot is created.
Real men don’t each quiche, and real horticulturists, arborists and golf course superintendents don’t use rock mulch. Replicate nature by using wood chips. Fortunately, Mother Nature isn’t choosy: pine needles, cypress pieces, bark nuggets, cedar chunks, even cocoa bean hulls or cottonseed hulls are good for trees. In extremely windy areas, rock might make sense, but mulching’s benefits of cooling the soil, suppressing weeds and recycling nutrients are lost. A particularly poor place to use rock is near the clubhouse, where a stray juvenile delinquent might feel the urge to toss a stone through the dining or ballroom window. A 2-inch depth is ideal.
Fertilizer
Guiding principle: Use less
Ornamentals generally require only one-third to one-half the amount of fertilizer that turf does. If the tree/shrub/perennial is allowed to recycle nutrients back to the soil through recycling as described earlier, it’ll seldom need fertilizer. Soil tests are the best way to ascertain whether your ornamentals need fertilizer.
Tree placement will also determine the need for applied fertilizer. As above, if the roots are covered with a non-pervious material or otherwise restricted, the opportunity for natural nutrient replenishment is lost. It’s quite common for trees under these conditions to develop nutrient deficiencies such as iron chlorosis. However, if trees are planted in a mass or grove with lots of room for their roots to expand in all directions, the need lessens dramatically.
Traditional “up and back” golf courses, or designs that incorporate trees between playing surfaces, can also favor tree growth. In these situations, trees often bisect roughs from adjacent holes. Most trees will produce lateral roots that extend outward twice the width of the drip line of the tree. Depending on the width of the rough and the amount of fertilizer applied, some nutrients can be used from applications made to maintain turf quality.
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Where ornamentals are surrounded by concrete, the root systems will be compromised. Mulching will cycle nutrients through the roots so the plants can develop properly. |
Water
Guiding Principle: “Just right”
In the story of Goldilocks and the three bears, the first bed was too big, the second was too small, the third was just right. So how much water is just right? Even though it seems simple, watering ornamentals is a four-step process.
• Find out the optimal level for the particular plant in question. Do some research by checking various references. The most convenient source is the care tag attached to the plant. These labels offer useful guidelines on sun/shade, plant height and desirable moisture content of the soil. Bulletins from the closest land-grant university or botanic garden can also provide the necessary information — whether the soil should be kept dry, moist or in between.
• Determine the moisture content of the soil in various areas on the course by probing the soil with a screwdriver or soil probe. Other stiff metal devices such as headless golf clubs or pieces of reinforcement bar can also be useful.
• If needed, irrigate to meet plant moisture requirements. While the sprinklers are running, measure irrigation amounts with collection devices. Just as with determining soil moisture content, the device to measure applied water need not be sophisticated; tuna cans and rain gauges work just fine.
• Following irrigation, measure the moisture content of the soil near the roots again to evaluate how well the root zone has been moistened. This final step is important because factors such as a slope or heavy clay soil can severely limit water infiltration.
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Ornamentals that are planted near or within maintained turf will require little or no additional fertilizer. If trees are planted in a mass or grove, nutrient replenishment through mulching is enhanced. |
Pruning
Guiding principle: “As needed”
Start with a thorough assessment of each tree or shrub. If you need assistance, don’t hesitate to contact an International Society of Arboriculture consulting arborist. These professionals can be of great help in sizing up flaws and assets of a tree and charting a course for future corrective action. Pruning is essentially a procedure that can correct some of the problems of the past. However, if it appears that the stability of a tree is in question, here’s a quick primer.
Consider “target” (potential for human injury or property damage) as it relates to the golf course. The location of the tree, especially certain tree parts such as overhanging limbs, should dictate the seriousness of the situation. The golf car paths, parking lots, tee boxes and greens are likely to be the locations on the course where tree failure could cause injury or death to golfers. Try to estimate the location of the potential impact of limbs dropping to the ground and the closeness to these vulnerable locations of human activity. A tree might be in pretty bad shape, but if it’s located at the back side of a green where balls seldom land, or is simply a screening tree in out-of-bounds, the target is fairly low. Turnarounds and clubhouses tend to be high targets.
Then, look for flaws, in this order of importance:
• Cracks. Vertical bark separation poses the most likely threat to tree failure. These are caused by frost, sunscald and mechanical injury. During storms or simply through time, the cracks widen and cause the tree to split.
• Decay. Many, if not all, trees have decay, so it’s a much more common flaw than cracks. Decay occurs as a result of an injury to the bark, usually when a limb is removed. This allows fungi to enter the cambium and sapwood, starting the degradation process. In general, if two-thirds or more of the heartwood of a tree is sound, decay is not a significant factor.
• Planting errors. Just as with watering, planting a tree is not as simple as it may appear. Common mistakes include planting a shrub or tree too deep, digging the hole too small, and forgetting to loosen any tangled roots in the root ball. Unfortunately, these errors stay with the tree its entire life.
• Undesirable developments. Over time, various problems occur, such as girdling roots and co-dominant leaders. If these problems are not corrected as they occur, they often lead to tree failure.
• Incidence of pests. Pests can degrade the structure and integrity of a tree or shrub. Scale, aphids, leaf blights, tip blights, needlecast and especially cankers can cause weakness that may lead to eventual demise.
• Health and vigor. This is a catch-all flaw, describing the tree’s overall level of health. Examine the growth rate, color and fruiting of the tree. If they are up to par, great. If not, consider influences such as drought, whether soil has been placed over the roots, trenching or digging operations nearby and soil type.
If the inspection has identified problem areas, keep balance in mind as you attempt to correct them. For example, a thick canopy for a small tree or large shrub can lead to more foliage disease because of less air flow across the leaves. Yet, severe pruning to open the canopy can be just as problematic. Sure, the pruning dries out the foliage, but it could also lead to increased suckering and weak growth in response. Growth regulators that suppress rampant lateral growth are present in the terminal buds of ornamentals. When terminals are removed, the side shoots grow wildly, creating a distorted appearance with weak structure.
Routine pest control
Guiding principle: “As needed”
Few pests justify routine pesticide applications, but some unscrupulous tree services still attempt to sell “prevention packages” or “ornamental pest control schedules” to superintendents or course owners at the beginning of a season, whether the trees on the course need them or not.
The soundest approach is to rely on regular inspections to determine whether pest control applications are necessary. For example, if your crabapples have a severe infestation of oystershell scale, several well-timed applications of a product such as horticultural oil are a good idea, followed by similar applications during the next year. But enough is enough. After a couple of years, fall back to inspection rather than prescriptive application. After all, if the tree/shrub is that prone to pests, do you really want it on your course?
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