Heavenly plumerias can survive in wet summer conditions


August 12, 2004


Victoria County Master Gardener


Plumerias, native to the Caribbean Islands, Central America and Mexico, were prized, worshipped and cultivated for thousands of years. Transported by ships, the trees are now found growing on sacred ground: temples, graveyards, and shrines throughout the tropical world - and they now also grace the subtropical area of coastal South Texas.


Plumeria fragrances are more varied than the blooms. Descriptions of fruity, citrus, fresh, spicy, or rose scents are far from describing their evocative complexity. Colors, petals and petal arrangements also vary tremendously.


There are "so-so" plumerias - and great plumerias. Start with a named variety with the particular characteristics you desire, as they are the best of many seedlings. The outstanding varieties might have great color, more inflorescences (bloom stalks), a longer bloom period, and/or beautiful fragrance.


Most of us in Texas keep plumerias in pots, or pots "plunged" in the ground for easy winter removal and storage. The compact shrub plumerias are ideal; they rarely grow out of reach or smell. Compacts, with their denser, shorter branching habits grow faster than expensive dwarfs, and bloom frequently, producing a great potted plant. Compacts also have a wide selection of beautiful and fragrant flowers and often are available from relatively inexpensive sources.


Some of the best varieties in compacts are Abigail, burning embers, Brittney, rim fire, Mardi Gras, Tahitian sunset, Maui beauty, and yellow jack. Other regular-sized ones, but with special flowers and fragrance, include San Germaine, Vera Cruz rose, Aztec sun and Negril.


Before purchase, do research, talk to knowledgeable nursery professionals, and check out the Plumeria Society of America Web sites, Garden Web or Yahoo Plumeria group postings. Another helpful site is www.plumeria101.com


Unrooted cuttings of named plumerias are the best bargain. Plumeria cuttings need dryness, warm rooting medium and bottom heat to root successfully. A good rooting medium is one-third peat moss and two-thirds perlite. Mix in an old glass bowl and sterilize it in the microwave for five to seven minutes on high to get rid of any pathogens that might rot the cutting. To root, use a 4-inch wide pot with higher sides such as a clean, black quart nursery pot. Ninety-degree soil warmth is required for optimum rooting. A larger pot may not allow the soil to stay warm enough or dry enough for rooting success.


The new cutting should have first dried in a warm, dry, shady area about 10 to 14 days after removal from the tree. Soak the cutting in warm water of about 100 degrees F for 10 minutes and then dip the bottom cut in rootone with fungicide. Position the cutting about 11/2 inches from the pot bottom and pack the damp mixture firmly around the cutting. Tape a couple of bamboo sticks to the outside of the pot with duct tape and tie the cutting so it won't sag or fall out of the mix.


After several days in shade, put the cutting out in full morning sun on hot concrete, or a black plastic plant tray. A little light shade in the afternoon in July or August will protect the cutting from sunscald. The best time to root cuttings is May-June, but they can be rooted through October with care. Warning: If heavy rain is predicted, bring the cutting under cover in the garage or under a porch.


A good indicator that roots have formed is the emergence of four full leaves on the cutting. Some plumerias root in two weeks, others in six months. I put about 2 tablespoons of water with a drop of Super-Thrive in the rooting medium every four to five days - and no more. If you receive a cutting that looks wrinkled and excessively dry, soak in clean water with a few drops of Super-Thrive overnight. After the soak, dip the end in the rootone and repot in a clean, dry potting medium. Plant in 3- to 5-gallon black plastic containers after rooting; if you have a fancy pot, put the black pot inside.


Use a well-drained, rich medium - good potting soil mixed with well-composted pine bark, worm castings and compost, and quality composted cow manure. Do not over-water, or feed immediately after planting. Start slow and gradually water completely every other day for well-rooted pot plumerias.


Plumerias are heavy feeders, and their plant food should consist of high phosphorus (middle number) and lower nitrogen (first number). Check for this fertilizer labeling. Too much nitrogen will cause growth, but no blooms and less branching. Feed every two weeks with both foliar and soil drench alternately of Peters Super Bloom Booster or Schultz Bloom Builder, both with a middle number of at least 50 plus trace elements. When I foliar spray - always in the evening in the coolest part of the day - I also add Spray and Grow and a wetting medium to insure even coverage of leaves. Alternating dry plumeria fertilizer with super phosphate monthly will also do. I add Epson salt to the pot at the beginning of the growing season, but this will burn leaves if added later.


Excessively wet conditions, like existed this summer, can bring problems to plumerias. Snails will climb up the plants and feast on the more delectable greener branches. The best control is Sluggo, or Schultz Garden Safe. They are safe for cats, dogs and earthworms; the bait contains iron phosphate, a good fertilizer for your plumies - but bad news for snails. Plumerias in wet soil for too long will show signs of oxygen starvation and waterlogging. Leaves will emerge curled up and the trunk will look wrinkled and feel soft. If this happens, gently remove the plant from the soil and check the roots. If the roots are rotting, wash them gently with clean water and a good plant and soil disinfectant such as Triple Action 20, then repot in new dry mix.


Plumeria rust, a fungus, appears as orange-yellow spots on the underside of leaves. The rust will not kill the plumeria but can defoliate it and slow growth - a natural process in the fall, prior to winter dormancy, but unwelcome in June, on your patio. Top-dressing the plumeria pot with cow manure can often control rust. Funginex or Bayleton liquid systemic applied weekly for several weeks will help, and while not necessary, both underside and top can be soaked, but always in the evening when it is coolest. Good infection control helps the most - even just pulling off affected "russty" leaves and disposing of them in the trash.


Hopefully, your plumeria cuttings and plants made it through this summer's wet June, and are blooming - but if they didn't, you will know what to do next year.