A garden element that is often overlooked in the design phase but is incredibly important in the long term is the structure and fertility of the soil. It's all about the soil. Unless a plant has good deep soil to sink into and thrive, it will languish. We now know that soil is more complex than once thought. Good soil structure and fertility are both necessary to promote optimum plant health.
Optimum plant health is necessary in order to fight off insects and disease. Organic farmers have found that when attention is given to the soil, in a scientific manner, most plants are able to fight off pests
In the Spring, when getting gardens ready for the growing season, I take note of struggling plants and work compost into the soil around them. I do not make assumptions about the condition of the soil, especially here on Cape Cod where the soil is young and marginal. About the only place good soil is found is in the hollows and marshy areas between eskers. we are primarily blessed with sandy soil or rock, boulder clay and gravel left over from glaciers. The Stone Bench above was built from rocks on site, which the conservation commission had mandated in this rocky conservation area.
Working compost into the soil is almost always necessary. The process of working in compost lets me see into the soil and see how rocky it is and what it might need. I have learned that the eye helps, but the scientists at the soil lab at the Extension Service in Amherst, MA give an excellent breakdown of the soil and what it needs. A test leads to and economical use of soil and amendments and is well worth the money. A full soil including measuring all nutrients, a graphical representation and analysis of the texture and grain size as well as testing for salts and metals, Ph, organic matter etc., cost about $150 with but prevents surprises down the road.
When large amounts of soil are moved onto a site it is best to have that soil tested. Dark does not always mean fertile and fertile does not necessarily mean a plant will grow. The size of the grains and the amount of organic matter are key. It is common practice to mix fill (subsoil) with compost and sell it as topsoil. This product is often dark but contains too much clay to maintain optimal growth. Clay holds water and is small amounts but too much and the plant will struggle with wet roots and poor air turnover in the soil.
-- Beach Roses and many of our native plants are well adapted to our sandy or gravely soils and will help to prevent erosion. Many plants such as azaleas and Rhododendrons need a more loamy soil to thrive and not fall prey to disease and insect predators.
Honey Bee collecting Pollen on Seaside Goldenrod.
The lovely Marsh Hibiscus , a native of our bogs and marshes will grow in many situations given enough water.
When wooded areas are maintained with open spaces, interesting perennials will often grow of their own accord. Spotted Wintergreen has many season interest with waxy white flowers, bright red berries and seed capsules that last through winter. Indian Pipe has no but gets nourishment through a mutual relationship with the soil fungus Mycorrhiza. Mycorrhizae fungus' are associated with healthy soil and are greatly desired. They benefit the soils they inhabit and increase the ability of many plants to fight off disease and insect pests. I often use Mycorrhizae fungus' in liquid form during new plantings and to help struggling plants. Getting Mycorrhizae established in the soil is always a priority.
Both Wintergreen and Indian Pipe are considered to be in the Heath family.
Above is an example of a Honey Locust that was failing. I was called to the property and noticed that the tree did not have a proper root flare. Upon excavation, it was easy to see that the problem was that the tree was planted too deeply in soil that contained too much clay. What had happened on this landscape was that the original landscape company had planted the tree at the proper depth but then the company that installed the sod raised the surrounding lawn up another six inches.
All photographs are the property of David Brogan and Second Nature