Total Plant Health Care (TPHC)

Total Plant Health Care (TPHC) is a method of understanding and implementing the maintenance requirements of plant material; TPHC is a holistic approach to the cultural, environmental, and human inputs to which our plants are subject. Understanding the interdependence of these inputs is of primary importance to the success of the landscape.

The following are general guidelines for the care of landscape plants; each suggestion must be viewed in terms of

(1) the particular site (soil, climate, topography, exposure, wind direction, etc.); and

(2) the plant type and specific requirements (deciduous, evergreen, soil/climate tolerance, hardiness, and intended use).

TPHC requires the gardener to use all available site and plant data and all available horticultural data to determine the correct maintenance input for the time and site specific situation. In other words, TPHC requires the gardener to use common sense.

Plant Selection and Layout

The success of landscape plantings begins with plant selection and layout; mature size, form, and color must be considered for proper placement. Develop a scaled plan showing mature plant forms, all structures, overhead and underground utilities, and any future improvements; note uses for various areas (entertaining, relaxing, study) and environmental conditions (summer breezes, sun angle, prominent views). Specific plant cultural requirements (soil, moisture, exposure, etc.) must approximate site conditions without major transformations of soil types or other physical alterations. The benefit of thorough planning is a landscape that offers beauty, harmony with the native surroundings and ease of care. The consequences of poor planning can be disastrous both aesthetically and economically.

Soil and Irrigation

The "ideal" soil for plant growth is composed of approximately fifty percent solids, twenty-five percent air and twenty-five percent solution (water). A fine-particle clay soil (small air spaces) is irrigated differently than coarse sandy soil (large air spaces). Clay soils can become waterlogged, depriving roots of needed oxygen; care must be taken to alter watering cycles to provide a damp but not saturated environment. Sandy soils require more irrigation to insure adequate root zone moisture. The site specific soil type (usually somewhere between the above extremes), the individual plant requirements and the present environmental conditions determine the need for irrigation. Example: we may need to water the moisture-loving dogwood ; (1) three times/week in sandy soil, (2) once/week in a clay loam or (3) five times/week in a sandy soil exposed to full sun and drying winds. The general rule is to water deeply and infrequently; this allows adequate moisture at all levels and encourages roots to follow the moisture downward. In the planter bed, basins should be built well beyond the dripline of the plant. In the "average" loam (halfway between clay and sand), one inch of water will penetrate one foot - deeper in sandy soils, shallower in clay. Plants growing in competition with lawn grasses should be monitored carefully; often, supplying additional irrigation, or creating a basin by removing sod and mulching, is necessary to provide moisture to the necessary depth.

Soil and Fertility

The "ideal" soil referred to above also contains three to five percent organic matter ( plant and animal remains); beneficial fungi, bacteria, yeasts, and other live soil microorganisms work to decompose organic matter into humus. Humus directly increases the plant's ability to assimilate food, as well as increased resistance to insects, disease, drought, and other stresses. We can pour on the chemical fertilizers, but if the soil is not alive with microorganisms, the effort and expense are futile; as well as altering and possibly polluting the natural environment. We strongly recommend the use of natural organic sources of nitrogen, phosphorus, potassium and all secondary and trace elements. Aside from the elemental plant food, these sources provide organic matter, essential microbial activity, and humus. As with all cultural inputs, precise fertility needs will vary with the specific soil type, climate, etc., and will vary according to the type of plant. Roses (and others) are heavy feeders - some plants require infertile soil. Clay soils, despite poor physical properties, are often rich in essential elements, while sandy soils leach soluble plant food and generally require more feeding. (another advantage of natural organic food sources is the slow decomposition to a soluble state - this results in prolonged, even availability of food). The ideal source of food for many plants is a two to four-inch mulch of rich compost, supplemented as needed with blood meal, bone meal, rock powders, and/or other natural food sources.

Pruning

Most landscape plants need regular pruning, whether to preserve a loose, natural form or to create a tight compact shape. Various "styles" of pruning are employed according to plant requirements and intended use. Fruit trees are pruned for production, hedges for screening, specimens for display or motif, etc. Use well-built, sharp tools - clean cuts heal, ragged or pinched cuts allow diseases and rot to enter the plant. The mature form should be visualized and each pruning session devoted to encouraging that form. Expert pruning requires a broad understanding of growth characteristics, cutting techniques, site properties, and other factors. Several important techniques must be mastered before the actual pruning work begins. We suggest reading a good pruning manual and/or obtaining lessons from an experienced pruner. Pruning is a fascinating art and science and is well worth the effort devoted to learning.

Insect Pests

Numerous scientific studies have shown that healthy, vigorous plants growing in well-balanced soil will resist insect damage. Even in the healthiest landscape, however, occasional control measures may be required. In our area, we have observed the following insects causing moderate to severe damage to ornamental plants: aphid, whitefly, tent caterpillar, cutworm, scale, and mites. All of these insect pests can be controlled successfully with natural, non-toxic substances. The best insect control is frequent monitoring; early detection of harmful insect activity allows for small, spot treatments or merely hand-picking. The use of non-toxic (except to target species) treatments insures that the natural insect predators (ladybug, lacewing, praying mantis, and many others) continue to help us control the "bad" bugs.

Other Pests

Deer are perhaps the most damaging of all pests in our area. We specify the number of deer-resistant plants, but a very hungry deer may eat almost anything ( except perhaps barberry ). Deer generally shun prickly growth - like the above and some of the evergreens, mahonia, holly, juniper, etc. The only foolproof deer control is a sturdy, eight-foot-high fence, though various smelly (to deer) substances like cayenne, blood meal, and eggs have been used successfully at certain times and locations. Ornamental trees are inherently deer resistant after growth has exceeded browsing height. Perhaps the only solution to the deer problem, aside from the fence, is a combination of proper plant choice, fall deterrent sprays, and a good deal of tolerance. Pocket gophers can also cause considerable damage in some areas; we have found that the proper use of the Mcabee gopher trap is the best control. Cats also will help control this pest.

Conclusion

Remember the word "specific": each site, time and situation have its own set of answers. By understanding both the aboveground and the belowground site situation, and by observing the progress of the garden through the seasons, the gardener can make the correct cultural choices. This common sense of knowledge continues to grow through the years - there is always something new to learn.