More Interesting Than Dirt

Gardeners should refer correctly to the essence of our gardens, which is soil, and avoid calling it “dirt.”

Most soils consist of three groups of particles: sand (the largest in size), (clay (the smallest in size) and silt. The percentages of sand, clay and silt determine the texture of the soil. The best soil for gardening, called loam, has nearly equal parts of sand, silt and clay. Soil with this texture has good balance between retaining and draining moisture.

St another level, garden soil is a living environment, an ecological system, with microorganisms, decaying organic matter, earthworms and other insects. Each of these components contributes to the soil’s habitat for flora and fauna. Living soil involves a vast number of interdependent activities, which combine to create a complex and dynamic environment. These functions are enough to keep soil scientists studying for their lifetimes and motivate gardeners to at least appreciate what is going on under the surface of their gardens.

Kids Pat Down Soil Image

Kids pat down soil around a navel orange tree they planted

By comparison, dirt might contain a good mix of sand, silt and clay, but lacks any of the organic components of good garden soil. Dirt can be regarded as raw material for conversion to garden soil by adding organic matter (compost); this process will provide food for beneficial microorganisms and support the eventual development of the ecological system.

Dirt with a less than ideal mix of sand, silt and clay often can be improved by adding compost. Adding sand to a clayey soil, or clay to a sandy soil, might seem like a good idea, but it very difficult to create a good mix and usually results in something like concrete. Just add compost.

When we think of things that we cannot live without, many people will list sunlight, air and water, but not include soil, which is the essential fourth contributor to life on earth.

With this in mind, soil scientists from around the world have joined to name 2015 as the International Year of Soils, with the goals to educate the public about the importance of healthy soils. The Global Soils Partnership, which includes the United Nations’ Food and Agriculture Organization, The Soil Science Society of America, and many other groups, is spearheading these efforts. We are pleased to support this educational initiative.

Screen Shot 2015-03-23 at 2.44.53 PM

The Partnership has identified a theme for the educational activities of each month during 2015. The theme for April is “Soils Clean and Capture Water,” which is timely during California’s current severe drought conditions. As a group, the monthly themes provide an overview of the many ways in which soils support the quality of life on Plant Earth.

  • January – Soils Sustain Life
  • July – Soils are Living
  • February – Soils Support Urban Life
  • August – Soils Support Health
  • March – Soils Support Agriculture
  • September – Soils Protect the Natural Environment
  • April – Soils Clean and Capture Water
  • October – Soils and the Products We Use
  • May – Soils Support Buildings/Infrastructure
  • November – Soils and Climate
  • June – Soils Support Recreation
  • December – Soils, Culture, and People

Each gardener can support the International Year of Soils, in these ways:

All plants respond to good soil!

More Interesting Than Dirt

Gardeners should refer correctly to the essence of our gardens, which is soil, and avoid calling it “dirt.”

Most soils consist of three groups of particles: sand (the largest in size), (clay (the smallest in size) and silt. The percentages of sand, clay and silt determine the texture of the soil. The best soil for gardening, called loam, has nearly equal parts of sand, silt and clay. Soil with this texture has good balance between retaining and draining moisture.

St another level, garden soil is a living environment, an ecological system, with microorganisms, decaying organic matter, earthworms and other insects. Each of these components contributes to the soil’s habitat for flora and fauna. Living soil involves a vast number of interdependent activities, which combine to create a complex and dynamic environment. These functions are enough to keep soil scientists studying for their lifetimes and motivate gardeners to at least appreciate what is going on under the surface of their gardens.

By comparison, dirt might contain a good mix of sand, silt and clay, but lacks any of the organic components of good garden soil. Dirt can be regarded as raw material for conversion to garden soil by adding organic matter (compost); this process will provide food for beneficial microorganisms and support the eventual development of the ecological system.

Dirt with a less than ideal mix of sand, silt and clay often can be improved by adding compost. Adding sand to a clayey soil, or clay to a sandy soil, might seem like a good idea, but it very difficult to create a good mix and usually results in something like concrete. Just add compost.

When we think of things that we cannot live without, many people will list sunlight, air and water, but not include soil, which is the essential fourth contributor to life on earth.

With this in mind, soil scientists from around the world have joined to name 2015 as the International Year of Soils, with the goals to educate the public about the importance of healthy soils. The Global Soils Partnership, which includes the United Nations’ Food and Agriculture Organization <http://www.fao.org/soils-2015/en/>, The Soil Science Society of America <www.soils.org/iys>, and many other groups, is spearheading these efforts. We are pleased to support this educational initiative.

Screen Shot 2015-03-23 at 2.44.53 PM

The Partnership has identified a theme for the educational activities of each month during 2015. The theme for April is “Soils Clean and Capture Water,” which is timely during California’s current severe drought conditions. As a group, the monthly themes provide an overview of the many ways in which soils support the quality of life on Plant Earth.

  • January – Soils Sustain Life
  • July – Soils are Living
  • February – Soils Support Urban Life
  • August – Soils Support Health
  • March – Soils Support Agriculture
  • September – Soils Protect the Natural Environment
  • April – Soils Clean and Capture Water
  • October – Soils and the Products We Use
  • May – Soils Support Buildings/Infrastructure
  • November – Soils and Climate
  • June – Soils Support Recreation
  • December – Soils, Culture, and People

Each gardener can support the International Year of Soils, in these ways:

All plants respond to good soil!

Gardening Close Up

 

We garden on different perspectives: specific when studying individual plants, and general when designing a landscape. We can regard gardening as a continuum with many points between its ends. This range of possible perspectives deepens our interest in gardening.

With all that in mind, where does the survey of a genus belong on this continuum? That thought came to mind during a recent talk by Brian Kemble, Curator of The Ruth Bancroft Garden in Walnut Creek, specializing in succulent plants.

Ruth Bancroft established this extraordinary garden in 1972 as her private collection. It was the first garden supported by the Garden Conservancy, and in fact inspired the formation of that nation-wide organization. The garden was opened to the public in the early 1990s and soon became managed by a non-profit corporation.

Brian Kemble 3-2015

Brian Kemble, Cactus & Succulent Horticulturist

Kemble has been involved with the garden continuously since 1980, and has brought his considerable knowledge of horticulture and his expertise in succulent plants to the cultivation and development of the garden. Ms. Bancroft, now 106 years of age, maintains her interest in the collection.

Kemble spoke to the Monterey Bay Area Cactus and Succulent Society, in Watsonville. His talk focused on the genus Gasteria, a South African member of the Aloaceae plant family, which includes other popular genera: Aloe, Bulbine, Haworthia and others.

The name of the genus Gasteria reflects its flowers, which to some observers are stomach-shaped (“gaster” is Latin for “stomach). The flowers hang from inclined long racemes, which can includes clusters of 100 or more flowers. The flowers range in color from pink to vermillion with yellow-green tips.

The genus includes 22 species, with rosettes ranging in size from the diameter of a nickel coin, to those with leaves a meter long.

Gasteria acinacifolia

This is a Scimitar-leaved Gasteria (G. acinacifolia), displayed at the meeting of the Monterey Bay Cactus & Succulent Society, as part of the monthly mini-show. (It won a prize in its category!)  This is the tallest of the Gasteria species, native to the Eastern Cape of South Africa.

Kemble showed examples of several Gasteria species, each of which is native to a specific area of South Africa. He also showed several hybrid forms, including at least one that he developed himself.

Gasterias are relatively easy to propagate from seeds, divisions or leaf sections. They are also readily crossed with other plants in the Aloaceae family, so we have cultivars called xGasteraloe or xGasterhaworthia.

Kemble provided an expert overview of this interesting genus Gasteria. Some members of his audience might have been inspired to collect different species of the genus, but others most likely learned about how any given Gasteria fits into the larger botanical context. This knowledge adds in subtle ways to the enjoyment of gardening.

To learn more about Gasterias and other succulent plants, visit the web site of the Monterey Bay Cactus & Succulent Society, and click on
Specific Resources. Gasterias, as you will recall, are in the plant family Aloaceae.

 

Pruning Salvias Hard

We want our gardens to look good, pleasing to eye, whenever possible, but occasions arise when our gardens need tough love.

Right now, in late winter, is one such occasion, particularly for salvias.

Salvias, also called sage, are excellent garden plants in a large and varied family. There are almost 1,000 species of salvias, almost all of which are native to one of three distinct regions: Central and South America, Central Asia and the Mediterranean Basin, and Eastern Asia. A few species are native to the United States.

Salvias are popular garden plants because the genus includes many forms, sizes and blossom colors to choose from, the plants are easy to grow, with few problems with pests and diseases, and drought tolerant. Many salvia blossoms are various shades of red. Here is an example the relatively uncommon Forsythia Sage (Salvia madrensis), native to Sierra Madre Oriental in Mexico, with yellow blossoms.

Salvia madrensis

Click to Enlarge

Salvias do require pruning, which is done best on an annual schedule. If your garden includes a lot of salvias, as does my garden, it is easy to skip a pruning session or two. As often happens, procrastination only postpones the task and does not eliminate the need.

When salvias are not maintained with regular pruning, they grow rangy and produce fewer blossoms. It is worth the effort regular pruning to control the size and shape of the plant, and stimulate blossoming.

There are two broad categories of salvias: perennial woody plants and deciduous soft-stem plants. Popular species in the woody group include Culinary or Purple Sage (S. officinalis), Autumn Sage (S. greggii), Germander Sage (S. chamaedryoides), Texas Sage (S. coccinea), and Baby Sage (S. microphylla). The best times to prune woody salvias, it is said, are lightly after the blooms fade (late spring or early fall, usually), and more heavily just as new growth appears at the base of the plant (late winter or early spring).

Popular plants in the category of soft-stem plants include Mexican Bush Sage (S. leucantha), Pineapple Sage (S. elegans), Brazilian Sage (S. guaranitica), Waverly Sage (S. waverly), and Gentian Sage (S. patens). These plants, which bloom on new growth, should be cut “to the ground” after the flowers have faded, or as new growth appears in the early spring.

When salvias have grown for two or three years without regular pruning, as just might have happened in my own garden, right now is time for rejuvenation pruning, also called catch-up time.

According to some advisors, pruning salvias involves careful planning and time-consuming snipping of individual stems, but when managing forty or fifty overgrown plants, the most practical tool is an electric trimmer, wielded with tough love.

We also shovel-pruned plants that had sprawled to form a large clump, moved larger plants that were encroaching into the pathway, and repositioned several low-growing, blue-flowered Germander Sages to form a border for this large collection of salvias.

Time will tell, but I expect that these plants will recover quickly from this hard pruning, , and respond with a fine new season of growth and blossoming. They are already producing new shoots.

Salvia corrugata, hard-pruned

Salvia corrugata, hard-pruned

If you are managing only a few salvias, you could prune individual stems and produce a more attractive result, but your plants are also likely to respond with a new season of growth and a profusion of flowers. Try a little tough love!

Learning More About Salvias

B. Clebsch. The New Book of Salvias: Sages for Every Garden. Timber Press, 2003.

J. Sutton. The Gardener’s Guide to Growing Salvias. Timber Press, 2004.

Basic Introduction to the Genus, on Wikipedia

Species of the Genus Salvia, from The Plant Encyclopedia

Cabrillo College’s Salvia Chart