Well-sited turf and ornamentals usually perform quite well. The sun, shade, soil and other essential input factors seem to come together in the right combination to allow for healthy growth and outstanding performance.
Sometimes, however, we don’t have the best of growing conditions, yet the expectation is to produce quality plants as if we did. What’s the best course of action in these situations? Each one has its own set of limitations and possible solutions.
Tees and greens
Trees and shrubs that wrap around the green often cast excessive shade that prevents the turf surface from drying sufficiently. This scenario is complex, with several factors leading to the poor performance of turf. Plants respond to shade by increasing stem elongation, reducing tillering and favoring leaf growth instead of root growth. All of these factors set the plant up to be much less tolerant to environmental stresses, daily maintenance and golfing activity.
Because of higher humidity levels and tender leaves, shade and inadequate airflow can cause a host of diseases, such as brown patch, dollar spot, Pythium blight and Fusariumblight.
To increase overall turfgrass health and to minimize your maintenance requirements, consider the following solutions:
- Thin out or remove shrubs adjacent to the turf. Use caution when considering the same treatment to surrounding trees. Avoid lion’s tailing – aggressive canopy density reduction – because when all the interior branches are pruned off, the tree can suffer from malnutrition or from sunburn, resulting in bark splitting.
- Increase airflow by installing fans that increase air movement across cloistered areas. This will alleviate layering of air and promote the introduction of carbon dioxide to enhance photosynthesis and reduce humidity levels for a lower incidence of diseases.
- Use plant growth regulators to reduce stretching/etiolation, while still promoting turf density.
When soils are under constant shade conditions and remain wet for extended periods of time, underlying issues occur, such as poor drainage from nonuniform soils. Some areas drain well, while some drain too well or don’t drain at all.
When shade is present, these nonuniform soils present even more of a problem than they do in areas that receive full sun. This problem of soil nonuniformity is then magnified by the inherent problem of reduced root growth of the plant because of shade.
Poor ornamental performance
Every plant on the golf course has its own range of tolerance in terms of sun and shade. As such, most turf species are considered to be sun loving like Sudan grass and field corn. Excessive shade creates problems with shrubs, ground covers and flowers as well. Powdery mildew, various leaf spots, stretched and etiolated growth, a thin canopy and greatly reduced flowering are among some of the common problems seen with ornamentals that are growing in excessive shade.
Chances are a significant amount of time has passed between the installation of the initial ornamental plantings and the observation of the current symptoms. Three solutions rise to the top in terms of future actions to address excessive shade:
- Removal of the plants that are poorly performing is one option. This is an excellent choice if they have become excessively leggy or are infested with insects or diseases.
- Another possibility is to simply move them to a sunnier location on the course. It’s helpful to start this approach with a look at other locations that may have “holes” or empty spaces where transplanted ornamentals would help to thicken, highlight or accent existing plantings.
- In general, ornamentals should be moved at a time that is conducive to their re-establishment. For example, in New England, cutting back and transplanting spring-blooming shrubs and perennials is best accomplished in late summer. This timing allows for regrowth of the roots and shoots and improves the chances of success.
- Perhaps the best long-term solution is a re-examination of the plantings in light of the shade cast on various parts of the course. This is a multistep process that takes into account many common sense and critical factors. In terms of the initial consideration, design or redesign, our colleague Steve Rodie, associate professor in the landscape architecture program at the University of Nebraska-Lincoln, suggests that a seven-step process is appropriate:
1. Accept the situation
– It is what it is, as they say. There’s no sense denying the problem of excessive shade. Instead,
2. Analyze facts and feelings
– Monitor and calculate the actual number of hours of direct sun, filtered shade and heavy shade for each area. Consider also the attitudes that green committee members, regular golfers and maintenance workers have towards the ornamental plantings. Next,
3. Define goals and objectives
– Think through the purpose(s) for the plantings in question. Are they strictly “window dressing,” or do they serve another function? Afterwards,
4. Generate ideas to achieve goals and objectives
– There’s always several ways to accomplish goals. Think of more than one. Then,
5. Select the best ideas or combination of ideas
– working with others, choose which plants should stay, which should go, and what others should be brought in. After selection,
– Remove, relocate and bring the new plants in. Chances are good that other changes should be made as well, such as incorporation of compost and implementing gradation, integration and improvement of bed lines. Finally,
– Design eventually involves starting over. Taking a good hard look and objectively evaluating the success of the redesign is important to the success of any landscape project. As such, they are never finished.
During re-evaluation and replanting, it’s helpful to take a step backwards and revisit the goals for each area. The basic action at this point is to recall the main purpose for the plant materials. In so doing the creation of descriptions or “program statements” will facilitate the process. For example, “under a shaded canopy, create a durable surface with views of multiseason appeal plant materials that facilitate walking and cart traffic.” These statements are a good foundation for both short- and long-term plantings.
Solutions to consider:
- Aerify affected areas to enhance positive air and water movement throughout the root zone. Team this will light applications of nitrogen to encourage plant health and root growth.
- Work the area towards greater uniformity in soil organic matter. Consistent aeration and topdressing will improve your soil structure and can go a long way towards creating more uniform drainage capacity.
- Consider the regular use of wetting agents to enhance vertical water movement through the root zone.
- Closely monitor soil moisture content and apply irrigation water only when soils change from wet to moist to dry. Then only spot-water if needed.
- Perform an irrigation audit and take steps to improve distribution uniformity. There are a number of sprinkler innovations on the market today, and the proper adjustments could improve irrigation efficiency and result in a reduction of total water applied.
Site inventory and analysis
A part of the aforementioned facts and feelings is a process of site inventory and analysis. Each is equally important, with the inventory comprised of a simple documentation of existing conditions. This is usually best accomplished with another person – having that second set of eyes is beneficial.
The analysis component is a set of value judgments that pertain to their worth and need for action on behalf of each element in the golfscape. In other words, is it a priority or not? Photos and notes for solutions and enhancements can help describe existing plants and situations.
It’s time to choose
Once program statements have been developed, site inventory and analysis performed, specific site conditions have been taken into consideration, irrigation adjustments are made, and traffic flow and existing vegetation have been evaluated, then it’s time to choose plants with shade tolerance. As the many options are considered, right plant, right place must be a guiding principle. For example, it can be quite tempting to overlook or ignore the soil requirements of a specific species in order to obtain the main feature of adaptability.
Develop a plant palette
It’s not all that complicated to develop a plant palette; in fact, it’s as easy as 1, 2, 3.
1. Use your Web browser to find the closest botanical garden or arboretum.
2. Find their suggested trees, shrubs, perennials, ground covers, ornamental grasses and bulbs.
3. Use Google Images, Pinterest or Yahoo Image Search to visualize.
Many other good sources exist, including university and supplier websites, All-America Selections, Proven Winners, UtiliTrees and STEPABLES.
As discussed here, a plant palette is simply a ready-to-go list of well-adapted plants for various areas of the course. Here is what a full shade palette might look like:
- Trees – not really applicable, as few tall trees are “shade adaptable.” The focus is usually on small trees.
- Small Trees – serviceberry, redbud, witchhazel, hophornbeam
- Shrubs – viburnums, dogwoods, oakleaf hydrangea, beautyberry
- Perennials – bergenia, Japanese anemone, clethra, ligularia, amsonia
- Ground covers – wintercreeper euonymus, Virginia creeper, plumbago, lamium
Of course, once this list is created, part shade and full sun palettes should be created as well.
A better course of action
Visiting a website is one thing, but seeing, touching and smelling the plants is a much better option. This can be done by visiting nearby arboretums, botanic gardens or other golf courses. These gems are easy to find and easy to visit.
Some classic choices include the Morton Arboretum and Chicago Botanic Garden in Illinois; The Garden in San Diego; the Desert Botanical Garden in Phoenix; Lauritzen Gardens in Omaha, Neb.; The Arnold Arboretum in Boston; Powell Gardens near Kansas City, Mo.; New Mexico State University Botanic Garden in Las Cruces, N.M.; The Butchart Gardens in British Columbia; and the Minnesota Landscape Arboretum near Minneapolis.
When visiting, write extensive notes, and think about diversity when choosing plant materials. Relying on too few species is a common mistake.
Whenever possible, list alternative species and cultivars. It’s hard to know when a replacement will be needed under shady conditions. When the need arises, such as a severe infection of powdery mildew, knowing of a potential replacement plant with resistance is a valuable piece of information.
A plant palette is not to be undervalued. It’s an indispensible tool for the long term as well as when you’re in a rush before a tournament or major event.