Keeping Plants Healthy in Rains

Many areas of the lower South are deluged extended rainy periods during our tropical storm season. Our summers are usually plagued by lack of rain, but occasionally an early-season Gulf storm blows through and leaves plants treading water to stay alive.

Provide Good Drainage
One of the most important gardening mantras next to "Add compost" is "Provide good drainage." Most plants suffer in soggy, wet soils, especially if that condition is combined with heat. Even plants we associate with moist soil, such as azaleas and hydrangeas, fail to thrive with waterlogged roots. Planting in raised beds can provide the drainage plants need. As a 90-year-old gardening sage friend of mine used to say, "You can always add water, but you can't take it away."

Controlling Fungal Diseases
Even though such wet conditions are ideal for fungal and bacterial diseases, I seldom have to spray pesticides in my gardens. The primary reason is that I choose plants adapted to our area that have excellent disease resistance. I also prepare soil properly before planting, paying attention to watering and fertilizing. However, in spite of my best effots, sometimes an extended rainy spell can be too much for plants, fostering leaf spots and fruit rots.

Controlling Powdery Mildew
The fungus powdery mildew takes a toll on many plants. It loves the warm, humid conditions of tropical storm season. University research has shown that both sodium bicarbonate (baking soda) and potassium bicarbonate solutions are quite effective against mildew and certain other diseases when sprayed regularly. Some new commercial products based on these ingredients are now available. Other low-toxicity options based on natural and elemental ingredients are appearing on the market to help us control diseases with minimal damage to the environment.

Give Plants Some Space
Crowding plants reduces air circulation, which means that foliage stays wet longer. Proper spacing of plants such as 'Longwood Blue' bluebeard (Caryopteris X clandonensis 'Longwood Blue') can mean the difference between a major disease outbreak and a minor cosmetic problem.

Frequent watering also keeps foliage wet more of the time and increases the likelihood of disease problems. Whenever possible, avoid wetting foliage at all. I have installed drip irrigation in several areas and notice a reduction in foliage diseases and some savings on summer water bills too.

Photo by Skip Richter/National Gardening Association

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