Royal palm trees are popular choices for landscaping in the warm, coastal climates of Florida and Southern California. They can grow to an average height of 50 to 80 feet, with foliage spreads of 15 to 25 feet. The green leaflet blades are evergreen and grow between 18 and 36 inches long. Showy yellow flowers appear in the spring and have a pleasant fragrance. Royal palm trees do not droop; they grow upright with a showy trunk. Royal palms grow best in zones 10 and 11 but can handle a minimal exposure to temperatures as low as 28.
Select an area of your landscape with full sun to partial shade to plant a royal palm. Test the soil before planting. The surrounding soil should be acidic to slightly alkaline with pH levels between 6.5 and 7. Soil test kits are available from local garden supply stores and online retailers. If your soil has too much acid or too much alkaline, you can increase the pH level by adding lime and decrease the pH levels by adding aluminum sulfate. Make sure that the soil drains well.
Plant royal palm trees in warm months when the soil temperature is at least 65. Dig a hole twice as wide as the root ball of the royal palm. The hole should be as deep as the palm's growing container. Situate the tree in the hole and backfill around the tree with soil, packing it firmly into place.
Build a soil barrier around the perimeter of the palm tree, eight to 10 inches from the trunk. The rim of the soil barrier should be at least three inches tall to form a dam around the circumference of the tree. Fill the area inside the soil barrier with three-inch layer of organic mulch. Water the newly-planted royal palm tree generously.
Water the royal palm daily for the first two weeks to help the tree become established. Place a hose inside the soil barrier of the tree and allow the water to soak in slowly. Gradually reduce the number of times you water the tree, leveling off to once each week. Royal palms are drought tolerant, but a newly-planted palm should be watered well.
Fertilize your royal palm tree twice each growing season, once in the beginning of the spring and once at the end of the summer. Make sure to purchase fertilizer specially formulated for palm trees.
Prune the dead fronds of your royal palm tree as needed. Take special care not to damage the trunk, as this is an invitation to insects and disease.