MASTER GARDENER TRAINING, THIRD WEEK'S REPORT – A CONTINUING SERIES

February 9 through February 11, 2010
By Peter Longley

Soils and Plant Nutrition

On Tuesday, February 9, the topic was Soils and Plant Nutrition. The presentation was made by Brie Menjoulet, Agronomy specialist from Hermitage, Missouri. She opened with the remark: "Without soil there would be no food, thus no humans." Soil is therefore as important to us as it is to the plants. It is our physical support; it provides those plants on which we depend with air, water, temperature moderation, protection from toxins, and nutrients. Soil is made up of mineral matter (sand, silt, clay, and nutrients), water, air, organic matter (residue from plants and animals) and soil organisms. Believe it or not 50% is air and water and 45% mineral matter. Organic matter is only 4% and organisms (microbes) count for only 1%. Soil texture refers to the percentages of sand, silt, and clay that comprise soil. This texture affects water drainage, soil fertility, nutrient leaching, nutrient availability, and the soil pH. The sand and silt provide the air and water space; the nutrients are found in the clay. Ideal soil should be 20% clay, 40% sand, and 40% silt. On a triangular Soil Texture chart you can read from the percentages whether your soil is clay, sandy clay, silty clay, sandy clay loam, silty clay loam, sandy loam, silty loam, or loam. Loam is the ideal. We then experimented with soil, making a 1-oz ball of it in the hand, squeezing it to make a ribbon about 2.5cm long before it breaks off. If you can't make a ribbon, you have loamy sand. If the ribbon is too long you are veering toward clay. If successful, wet a small pinch and rub it in the palm. If it feels very gritty it will either be sandy loam, sandy clay loam, or sandy clay. If it feels very smooth it will either be silt loam, silty clay loam, or silty clay. If there is neither grittiness nor a very smooth texture, it will be, loam, clay loam, or clay. Sand is mostly quartz and particles are easily seen. Silt expands and contracts and gives cracks in soil, not necessarily a good thing. Clay and loam are the good soil, but loam is best.

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MASTER GARDENER TRAINING—FOURTH WEEK

February 16 through February 18, 2010

By Peter Longley

ANNUALS AND PERENNIALS

Xeriscape

On Tuesday, February 16, the class was on Annuals and Perennials. The first speaker was Barbara St. Clair, Master Gardener in charge of the Xeriscape Garden in Springfield. This is the smaller of two gardens in Springfield maintained by Master Gardeners. The name baffles many people, but it comes from the Greek 'Xeris' that means dry. The Xeriscape Garden was designed to be a dry garden that could easily adapt to traditionally dry Missouri summers (recent years, however, appear to show a changing pattern). Forgetting the Greek, Barbara St. Clair wanted us to see the garden as a 'Wise Water Garden'. About one third of the garden is wet, furnished with an irrigation system at about 1" rainfall a week, a second third is drier, demanding about ½" a week. Finally, there is the third that is completely unwatered. Barbara then listed with illustrations the surprising number of perennials that thrive in the dry third. There were strong links in this selection with the plants found in the full sun English Garden at Close Memorial Park: Agastache, Penstemon, Liatris, Catnip, Golden Rod, Feather leaf Coreopsis, Yarrow, Gaillardia, Lavender (has suffered in recent years from wet rot in the winter), Dianthus, Echinacea, Artemesia , Crepe Myrtles and Russian Sage. There were other plants that are not found in the English Garden at Close Memorial Park, but that at some time could be tried: Callirhoe, Euphorbia, Echinops, and Missouri Evening Primrose among them. With our fluctuating rainfall in recent years, Barbara St. Clair gave us the advice: "The plants have taught us what they need." She cited the success they have had with Digitalis in full sun, something we have not had much success with at Close Memorial Park. With this came a very important piece of advice—the most important maintenance is to make frequent visits to the garden. Just observing the plants, or as I would like to say, "talking to your plants," allows them to tell you what they need. Keep checking the garden out, even when it is well established. Importance, however, was stressed on soil conditions and the addition of appropriate organic matter. As always, select plant material that is appropriate to your climatic zone. You may, however, be surprised how many plants are considered xeric once they have established themselves and when properly cared for. Dry shade plants include Acanthus Spinosa and Acanthus Mollis. From your selection, plan the garden according to mini-zones to help their needs. For example, tough, drought tolerant plants should be in full sun areas, less tolerant plants in partial shade, and the more delicate or demanding plants close to the water source. Note the obvious, hydrangeas like to be near water source. The importance of mulching was again stressed. Shredded bark and compost is used at Xeriscape. Mulch moderates the soil temperature, holds moisture, slows erosion, and suppresses weeds that will compete with your plants for food and water. It also decomposes and feeds the soil. Good advice, once the garden is established in its mini-zones, is to base your watering schedule on the needs of the plants and not on an arbitrary schedule. Eventually, at least in the dry zone, a xeriscape garden will survive pretty well on its own.

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