Mark Takemoto shows two of the colorful ixora varieties.
Photo byKen Sakamoto, Star-Bulletin
Common varieties are big plants such as Super King with large dark red clusters of flowers, King with orange flowers and Yellow Thai. They grow to 5 feet and make spectacular hedges.
The most popular dwarf varieties include the round leaf Thai with bright red flowers, the white Thai and Millionaire whose flowers are the same color as puakeni-keni. These are about a foot tall.
The easiest method of propagation, Takemoto said, is from cuttings. Cut off a branch with at least three nodes - the bumps that remain after the leaf has fallen off - about 8 inches long. Remove the flowering head but keep the leaves, cutting each leaf in half across the center rib.
Dip the cut end of the branch in a root hormone such as Rootone and poke the cutting into a pot filled with potting soil. The lowest node should be below the soil, and at least two nodes above.
Put the pot in filtered sunlight and water daily. Roots should form within 4 weeks. At 6 weeks, repot into a bigger pot, and move into full sun. Ixora sends out underground runners that pop up around the garden. The runners can be transplanted, or at least removed when they are young .
"Ixora will grow anywhere, but it prefers a loose, sandy soil," Takemoto said. "It is among those plants that are called acid loving." Fertilizer, he explained, can provide acid to the soil which makes certain nutrients more available to the plant. "Look for a higher nitrogen content (the first number in the fertilizer formula) - something like 10-5-10 or 18-7-10. Often the bag will say on it, 'For acid-loving plants'," he said. Takemoto suggested raising the acid level of your soil by sprinkling 1 tablespoon of epsom salts (magnesium sulphate) mixed in a gallon of water around ixora plants. This also works with gardenias and azaleas.
For the best flowers and a compact plant, ixora needs full sun. Takemoto said it will tolerate filtered sun, but not full shade. Water according to the weather, he said, because ixora is drought tolerant. Plants in Nuuanu and Palolo probably never need watering. In Ewa Beach or Hawaii Kai, water once or twice a week.
So what can go wrong? Bugs are one thing, pruning is another. That nasty black stuff that shows up too often on ixora leaves is sooty mold, and it's bad news. "It lives off the honeydew exuded by scale," Takemoto explained, "so the first thing you have to do is to get rid of the insects. When you get rid of the scale, the food source for the sooty mildew is gone, and in time it goes away."
While soap solutions provide temporary relief, he recommends a mixture of Malathion and Volck oil. The Malathion kills the scale and the Volck oil causes the sooty mold to fall off the leaves. Read the label carefully, and be prepared for an unpleasant odor. Scale can also be controlled, but not as quickly, by pyrethrum.
Ants on your plants are protecting the scale by chasing away lady bugs and other predator insects (no, we don't know how, but the ants do), because the ants, too, are hooked on the honeydew.
Ants carry the scale from one plant to another to ensure their supply. If you get rid of the scale, you get rid of the ants. The downside of this is that they may then head to your kitchen for snacks.
The taller varieties of ixora make good hedges. Dwarf varieties can be grown as borders. Takemoto recommends placing large ones 4 to 5 feet apart. If you plant them closer, they will crowd each other out as they grow.
Because they grow so slowly, your kids may be in college before the hedge is up.You can speed the process by staggering plants in a sawtooth pattern, but it will take more plants.
"A regular light pruning improves flowering," Takemoto said. "Don't wait until the plant is too big and then hack it all back. The flowers grow at the tips of the new shoots so you get better flowers by pruning gently and only when necessary."
Hedges, no matter what the plant material, should be pruned so that the top is slightly narrower than the bottom. "If you prune it square, the bottom declines and the top grows faster so you end up with a V shape," he said.
While ixora flowers are a burst of beauty on the plant, they don't hold up well as cut flowers. "Maybe two days at the most," he said. "But they're gorgeous while they last. And you don't mind cutting them because you'll get more pretty soon." That's a good deal.
