Royal palm tree seeds propagate readily and often sprout on the ground beneath the tree. Flowers develop on mature trees throughout the year, and produce elliptical brownish-purple fruits about 5/8-inch long. Fully ripened fruits drop from the tree and each bears a single light brown seed. While germination can be as slow as 60 days under natural conditions, your carefully tended Roystonea may sprout in as little as two weeks. Royal palm tree seeds are somewhat forgiving of error and can even be stored for a short time if you're not quite ready to plant when you collect them. They'll perform best during the warmer months, when temperatures range between 86 and 95 degrees F.
Collect your royal palm seeds as soon as they drop from the tree. Seal those you're not ready to plant in an airtight plastic container or a plastic food storage bag. Store them out of direct light at room temperature for up to a month.
Put on some work gloves to clean your royal palm tree fruits because the pulpy flesh that encases the seed contains a skin irritant. Use a sharp, clean knife to remove the flesh. Rub the seed vigorously with your fingers under cold running water to remove any remaining pulp or flesh.
Place the royal palm seeds in a plastic or glass container and cover them with water. Place the container in a spot out of direct sunlight to soak for five to seven days. Change the water daily and plant the seeds immediately following the soaking period.
Fill a well-draining 2-inch pot about ¾ full with a mixture of equal parts peat moss and perlite. Set the pot in a shallow container of warm water until the surface feels evenly moist, but not soggy or wet. Remove it from the water and allow it to drain for about an hour. Plant the seed and cover it with the germinating medium to a level approximately equal to its diameter.
Set the pot outside in direct sun until the royal palm seed sprouts. This can take anywhere from two weeks to two months. Water just enough to evenly moisten the potting mix when the surface begins to feel dry to your touch. Don't allow it to dry out.
Move the new sprout into partial shade as soon as it emerges. When the plant is a little older, it will appreciate full sun. But at this time it's best to protect the youngster from brutal sunshine. Water enough to keep the surface of the planting medium uniformly moist but not wet or soggy. Don't allow it to dry out.
Transplant your royal palm tree seedling when it has formed four leaves. It's best to do this during the warmest months of the year to avoid transplant shock. Step it up to a 4-inch pot, or one just deep enough to accommodate the long taproot without curling it. Use a mixture of two parts peat moss, one part wood shavings and one part pine bark. Plant the seedling so that the point where the stem meets the roots is just above the surface of the soil. Water just enough to uniformly moisten the potting mix.
Place the royal palm tree seedling in partial shade until you notice new growth, in about three to four weeks. Gradually acclimate it to full sun over a two-week period. Keep the soil uniformly moist but not soggy.