You can grow plumeria in Southern California if temperatures in your area generally stay above 40 degrees. They grow best with daytime temperatures in the 80s and 90s and nighttime temperatures in the 60s and 70s. Plumeria are the tropical plants with fragrant flowers that Hawaiians use to make leis. They flower profusely and the flowers last for a long time both on the plant and as indoor bouquets.
Choose a site for your plumeria that is in full sun. Plumeria produce the most flowers if they are growing in full sun. They will grow in the shade, but they will produce more foliage and fewer flowers. The soil should be sandy and well drained. Don't plant them anywhere the soil is soggy. Plumeria grow well alongside cacti and succulents.
Dig a hole slightly larger than the root ball of the plumeria you are planting. Place the root ball into the hole and gently firm the soil when back filling. Give it a little water to settle the soil around the roots, but don't soak it.
Feed and fertilize your plumeria weekly with a high-phosphorus fertilizer. All fertilizers are labeled with the percentage of their active ingredients, such as 10-50-10. This fertilizer has a high middle number, which stands for phosphorus, which helps plants grow more flowers. Use a liquid fertilizer with a high middle number and spray the stem and foliage of your plumeria. Don't forget the undersides of the leaves.
During the dry season in Southern California, don't water or feed your plumeria. They naturally go dormant and will survive without them. Once the "rainy" season begins they will begin to grow again. You should then begin to water them regularly and feed them weekly.
Plumeria are tropical plants that suffer when exposed to temperatures below 50 degrees. Exposing them to temperatures below 40 degrees is usually fatal. However, well-established, healthy plumeria can withstand short periods below 40 degrees without serious setback.