Plumeria Care in Hawaii

Mulch

• Organic mulch spread around the plumeria tree helps retain moisture, reduces weeds and protects the tree from mechanical injury from lawn equipment. A 3- to 4-inch-deep layer of chipped wood, macadamia husks, shredded tree bark or shredded coconut husks should be spread around the tree. The mulched area should be a 3- to 12-foot-diameter circle with the tree at the center. Pull the mulch 1 to 2 inches away from the tree's trunk. Fluff and turn the mulch every six to nine months and add fresh mulch to maintain it 3 to 4 inches deep.

Water

• Plumerias need regular water, especially when they are first planted and during dry periods. Give less water more often to trees planted on shallow or clay soil. Give more water to plumerias in sandy soils that dry quickly. Plumerias planted in loam or sandy loam soil that is reasonably deep and does not dry quickly should be watered two to three times per week for the first month. Once or twice per week should be enough for the second through the sixth month. For the remainder of the first year, a deep watering once or twice per month should be enough, although more frequent watering will be needed during dry periods. In the second and third years, water the tree once per week if it doesn't rain. Supplemental water is extremely important in summer and fall. After the fourth year, the tree should receive 1 inch of water per week through rain or supplemental watering.

Fertilizer and Pruning

• Plumerias should be fertilized with 10-30-10 fertilizer at a rate of 1 pound of fertilizer for each 1 inch of trunk diameter. Sprinkle the fertilizer over the root zone around the tree, extending to 2 feet outside of the edge of the tree canopy. Apply fertilizer every three to four months. Plumerias can be pruned in the winter after deciduous trees lose their leaves. Extreme pruning will reduce spring flowering but broken branches should be removed. Bent, shriveled branches infested with stem borers and should be pruned off and removed.

Diseases and Pests

• Plumeria rust may occur after extended rainy periods, causing an orange powdery coating or blisters on the bottom of the leaves and the infected leaves may drop. Treatment with fungicides is not usually recommended as the damage is rarely severe. Blossom midges, mealybugs, mites, scales, thrips and whiteflies occasionally attack plumerias. Blossom midges lay their eggs in flower buds and the maggots feed on the buds. Remove and destroy infested buds from the tree and the area around the tree. Infestations of mealybugs, mites, thrips and whiteflies can be reduced with a strong spray of water from a garden hose several times per week, being careful to spray the undersides of the leaves. After the infestation is reduced, spraying once every week or two should keep it under control. Scales can be removed by hand. Branches heavily infested with scales and thrips should be removed and destroyed. If plain water is ineffective, 1 tablespoon of mild dish detergent can be mixed into 1 gallon of water and sprayed to kill mites, scales and whiteflies. Place the mixture into a garden sprayer and spray the insects directly as well as the leaves and stems.