The bushy-frond foxtail palm (Wodyetia bifurcata) looks elegant when it's healthy and well cared for, but if nutritional deficiencies set in, brown leaf tips ruin its appeal. With the right nutrients, this fast-growing drought-tolerant palm will keep your garden shaded with its 20-foot canopy while bringing an exotic element to the landscape. The foxtail palm grows in U.S. Department of Agriculture plant hardiness zones 10 through 11. Foxtail palms prefer well-drained and sightly acidic soil and perform best grown in full sun but tolerates shade. The palm suffers damage when temperatures drop below 30 degrees Fahrenheit.
Apply a palm-specific, 8-2-12, slow-release fertilizer every three months to the soil. Use 1 1/2 pounds for every 100 square feet of canopy size. Estimate the square footage of the canopy by measuring the area from base of the trunk to the line under the outermost tips of the fronds. If you end up with a 10-by-10-foot-area, for example, the palm has a 100-square-foot canopy. Spread the fertilizer evenly under the foxtail palm's canopy and do not allow the fertilizer to butt against the trunk. Water the fertilizer into the ground after applying.
Even with regular palm-specific fertilizer, foxtail palms can develop magnesium and potassium deficiencies, especially if the soil has a high pH. A magnesium deficiency turns the outer edges of the fronds pale brown and dead-looking. Potassium deficiency causes spots that appear translucent, dead tips and often, a general orange color near the base of each frond. To correct magnesium deficiency, use supplemental magnesium sulfate at a rate of 1 to 3 pounds per tree. For potassium deficiency, spread potassium sulfate -- 3 pounds for small trees up to 8 pounds for a mature 30-foot foxtail palm -- of potassium in addition to the regular fertilizer. Reapply every three months until the problem improves, which can take several years to correct, once the palm suffers the deficiency. As with fertilizer, spread evenly under the palm's canopy, not allowing the product to butt against the trunk and water in well.
Water deeply when the top 2 inches of the soil dries out. Water evenly over the palm's root zone, avoiding the fronds themselves and watering to a depth of approximately one foot. If your foxtail palm is growing near a lawn or in a garden bed, you likely won't have to water it at all. Not only is this palm drought-tolerant, it's also sensitive to excessively wet soil, especially when grown in containers. Symptoms of overwatering include fungal diseases, nutritional deficiencies and splitting of the trunk. Make sure the area drains well and avoid watering until the top of the soil is dry.
Cut off dead fronds where they attach to the trunk. A small tree saw works well to cut through the tough fiber stalks. For smaller fronds, a pair of loppers will do the job. As new fronds grow out of the center, the oldest fronds at the bottom eventually die. Trim the dead material any time of year, but wait until each frond is completely brown before you remove it. The palm is still receiving nutrients from partially green fronds and removing the frond before it's completely dead can lead to nutritional deficiencies. Before and after pruning, clean the saw blade or pruning shears in a solution of equal parts rubbing alcohol and fresh water and air-dry them.
Pests and Disease
Foxtail palms rarely suffer from pests and only occasionally from disease problems. One fungal disease to keep an eye out for is leaf spot, apparent by the dark to light brown irregular spots and patches that appear on the fronds. Focus all watering on the soil under the canopy, avoiding wetting the leaves. While unsightly, leaf spot rarely causes severe problems or needs treatment.
Foxtail palms produce striking red seeds that grow in clusters out of the trunk. While attractive, the seeds are poisonous. Keep the ground raked to prevent children or pets from consuming the seeds. Gardeners can prune off the seed stalks at any stage of development, as removing the stalks will not damage the palm's growth.