Signs of Boron Toxicity
Boron toxicity symptoms usually aren’t the result of small amounts of boron generally found in soil. However, some areas have boron in the water in high enough concentrations to cause boron toxicity in plants. Plants with too much boron initially display yellowing or browning of foliage. Leaf tips become dry, with the symptoms eventually taking over entire leaves. Boron toxicity symptoms are different depending on the plant, and instead of damage to the foliage, some plants may ooze a gummy substance from the branches or trunk. Stunted growth is common, and fruit trees may be less productive. If you suspect your water contains high levels of boron, you can confirm your suspicions (or not) by having your water tested.
Treating Plants with too Much Boron
If boron levels are high, there isn’t too much home gardeners can do unless an alternate water supply is available. Boron is more common in spring water or well water and less likely to be found in municipal water supplies. One possibility is to collect rainwater in a tank for irrigation purposes. Usually, the best solution is to rely on plants that are less sensitive to boron. Some plants have a fairly high resistance to boron. These may include:
Lavender Oleander Yarrow Red hot poker Roses Grapevines
Others, such as citrus, figs, and peach trees, struggle greatly with signs of boron toxicity. Many vegetables are sensitive to boron. If your boron levels are high, your garden may be limited to beets, parsley, asparagus, and tomatoes. Others that may do well and be worth a try depending on the level of boron include:
Cantaloupe Lettuce Squash Cabbage Artichoke Corn
Acid-loving plants, such as azaleas and camellias, tend to be negatively affected by high levels of boron, so it may pay to look into plants that do well in alkaline soil. Perennials that remain green all year are often more susceptible to damage, as the boron accumulates in the leaves. Plants with grayish leaves tend to be more resistant to boron damage.
