The desert rose (Adenium spp.) is a member of the dogbane family and a relative of the oleander. Sometimes simply referred to as adenium, this African native can be grown as a shrub or tree or used in bonsai. In nature, some species grow to 10 feet in height. Desert rose seeds can be started year-round in USDA Hardiness Zones 11 and 12.
Soak the desert rose seeds in a dish of warm water for two hours.
Remove the seeds from the water and place on a paper towel. Pour fungicide powder, at the rate suggested on the package, into a bag and place the seeds inside. Shake the bag gently to coat the seeds with fungicide. Place them on a clean, dry paper towel until ready to plant.
Fill the planting pot with equal parts perlite and peat moss. Water the medium until it is saturated and water drains from the bottom of the pot. Allow the pot to drain completely.
Place the seeds (three seeds in each 4-inch pot) on the surface of the soil and cover with a very thin layer (1/4-inch or less) of moist peat moss. The seeds should be barely covered.
Cover the pot with plastic wrap and place it on the heat mat, set to 85 degrees F, in an area that is well-lit but out of direct sunlight. The soil should remain moist while it is covered with the plastic wrap. If it appears to be drying, mist the surface with a plant misting bottle filled with water.
Remove the plastic wrap from the pot when the seeds germinate, which should occur within one to two weeks.
Prepare the seedlings' permanent garden location, in an area that receives full sun, by tilling the soil to a depth of 8 inches. Use a garden fork for this task. Add 3 inches of coarse sand and 3 inches of peat moss to the soil and mix it to a depth of 8 inches.
Transplant the seedlings into their permanent location when they have six sets of leaves. This should occur within two months of germination. Dig holes in the prepared planting area that are the same depth as and twice the diameter of the planting pot. Remove the desert rose seedlings from the pot, being very careful not to break the roots. Place the roots in the hole and backfill with soil, tamping the soil around the base of the desert rose to ensure good contact with the soil.
Water the desert rose seedlings until the top 4 inches of soil is moist.