The Mexican fan palm, or washingtonia robusta, grows to tremendous heights of 100 feet or more. The bright green leaves, spiky stalks and shaggy trunk of the Mexican fan palm make it an interesting focal point for the home landscape. Able to survive in temperatures as low as -7.78 degrees C and favouring USDA hardiness zones 8 through 11, this cold hardy palm produces black fleshy fruit that measures less than an inch, complementing its showy, cream coloured flowers. Caring for a Mexican fan palm begins at planting and continues as the tree matures.
Provide the Mexican palm tree with well-drained, alkaline soil that receives full sun. A pH above 7.0 qualifies as alkaline. You can test the soil with a pH testing kit purchased from a nursery or garden centre. If the pH measures below 7.0, you will need to add lime according to label instructions to raise it.
Dig the planting hole for the Mexican fan palm twice the width of its root ball and just as tall. The root ball should sit in the hole with the graft union (transition point between the trunk and the roots) above the soil line. If the graft union is below the soil line, your hole is too deep. Backfill the hole with the original soil from the hole and tamp the soil with your foot to remove air pockets.
Keep the soil around the Mexican fan palm moist before and after planting. Water the Mexican fan palm using a soaker hose, which will provide deep watering. Although palms like their soil moist, they do not like it wet, so allow the surface of the soil to dry out in between waterings.
Feed the Mexican fan palm a slow-release fertiliser after its first growing year. Most palms benefit from fertilisation in the spring, summer and fall. Follow the package instructions to determine allocation amounts and time frames.
Prune the Mexican fan palm at least once a year. Use a pair of pruning shears or a pruning saw on young trees. Mature trees that are beyond your reach may require the help of a skilled arborist.
Mexican palms are prone to infestation by the coconut mealy bug, palm leaf skeletonizer and the palm platid planthopper. Contact a skilled arborist to help rid your tree of these pests.
Do not overwater the Mexican fan palm. Standing water can cause root rot, which can kill the palm.