By Don Trotter Ph.D.

Hello fellow Earthlings, and welcome to a much-requested discussion on acid-loving plants and their care. For some of you, these plants present a real dilemma. They are beautiful and plentiful in some parts of the country and a real challenge for gardeners in other parts of the country. This discussion is intended to give some basic outlines for growing this wonderful and diverse group of plants. If any of you have specific needs or challenges regarding acid lovers, I urge you to contact me for some free advice.

Acid-loving plants are just that. This group of plants thrives in soil conditions that are acidic in varying degrees. Some acid lovers really appreciate slightly acidic soils and others prefer to live in conditions where the soils are so acidic that few other plants are capable of growing. We will be discussing the more subdued acid lovers this time. But any discussion needs to start with soil. In areas where rainfall is common during the warm season, soils are often acidic. In these regions, rhododendrons, azaleas, hydrangeas, camellias, magnolias, and a number of other popular acid-loving plants grow very well. In areas where rainfall is not plentiful, soils have a tendency to be somewhat alkaline. In these regions, acid-loving plants are more of a challenge.

The pH of a soil is critical to success with acid-loving plants. In some acidic soils, little mineral and nutrient management is required other than providing adequate levels of nitrogen-N, phosphate (phosphorus)-P, potassium-K, and calcium-Ca. Other acidic soils may require the addition of magnesium and some additional trace minerals that can be easily identified by having the soil tested. A number of agricultural agencies or garden centers offer soil-testing services that will provide you with a wealth of information about the quality of your soil.

Where soil pH is higher than neutral (above 7.0), acid-loving plants may suffer from a lack of nutrients and minerals that are bound or missing. In these alkaline soils, many are often clays where essential minerals like iron and sulfur are in short supply or are bound by other minerals under the conditions of a high pH. Salinity can also be a problem because of a lack of rainfall to percolate salts through the topsoil. Acid-loving plants are notoriously salt-intolerant. To exacerbate the salt problems, commercial chemical fertilizers are often a combination of salts that can accumulate in soils that don’t drain well. This condition of poor drainage can often be remedied by the addition of calcium sulfate (Gypsum) or fossilized Kelp (Kelzyme) calcium.

One thing to remember is the most common source of calcium —  lime — will adjust pH values even higher in alkaline soils and should be avoided. The best way to adjust soil pH values lower is to add soil sulfur in small amounts over a course of time. Iron sulfate is also a fairly good pH adjuster as well as a source of essential iron. There are many iron products on store shelves but few are natural/organic so be wary of them. Organic chelated iron and mineral supplements for soil are the best ones and are immediately available to the plant to correct imbalances.

My favorite way to ensure that soil pH is balanced so that acid-loving plants can inhabit the garden with other plants is to apply lots of organic matter to the soil in the form of compost and mulch. These organic materials will keep the wide diversity of micro-organisms healthy and vigorous. In turn these microscopic animals and plants will work to convert nutrients and minerals so they are continuously available to plants. This will make mineral and nutrient deficiencies in plants less of a problem so your plants grow and flower with more vigor and with fewer problems from pests and disease.

Acid-loving plants, and all other plants for that matter, are more pest and disease resistant when balanced nutrition is provided. Just like you and I. When you provide this balanced environment for them to grow in you will quickly see how easy it is to cultivate acid-loving plants in almost any garden, almost anywhere. The key to success is to remember that acid-lovers are just those, acid-lovers. That way you can form a strategy for growing them successfully and they can supply you with years of beauty, fragrance and pleasure in return.

Next time we will be discussing fall in the garden. It will be a two-part discussion on putting all of your precious plants to bed for the winter and enjoying that “last blast” of warm season joy in your edens.  See you in the Garden!

Got questions? Fax the Doc at (760) 632-8175 or e-mail him at Don Trotter’s columns appear nationally in environmentally-sensitive publications. Look for Don’s new book “Natural Gardening A to Z” from Hay House Publishing at bookstores near you or call (800) 654-5126,

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