Friday | December 15, 2017
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Tropical Gardening: Poinsettias for holiday color

Poinsettias are like Christmas budgets this time of year.

Both are in the red.

So if you want to give inexpensive gifts with a personal flare, living plants that fit the personality of the recipient are ideal. However, be careful with your choices. There is a big difference between a succulent plant that might have romantic inferences and a spiny cactus that says something else.

Although it finally feels like fall, and we have been seeing Christmas decorations in some stores even before Halloween, the holidays don’t seem real until we get our Thanksgiving meal digested. This year was particularly confusing with record warm temperatures and rainfall.

Poinsettias are blooming in some areas and not doing well in others.

Poinsettias, especially in Kona, Ka‘u and Kohala, are in spectacular color, but they do not like wet feet, so they are not always happy in East Hawaii.

Although mainland folks think of poinsettias as a Christmas flower, for us they bloom from November-March. Instead of being little potted plants, in Hawaii they become large bushes or even small trees when planted in the garden.

As you drive along island roads now, you also are likely to see large white flowering bushes with miniature poinsettia-like bracts. This is sometimes called the white poinsettia or Snows of Kilimanjaro. This close relative is Euphorbia leucocephala.

So if you don’t have a showy supply of poinsettias in your home and garden, now’s the time to start looking for them in the marketplace.

Purchasing potted stock from a garden center or nursery is the easiest way to establish plantings of this holiday ornamental. However, some green thumb operators scavenge the neighborhood for hardwood cuttings when fellow gardeners prune their poinsettias following the flowering season. Getting plants this way can make you feel like a turkey if you choose cuttings from disease infected plants. If you get healthy plants, you can be sure to avoid “fowl” play.

There are a number of poinsettias available. The bracts surrounding the small inconspicuous flowers come in traditional reds or you can enjoy color combinations indoors and in the garden if you mingle the red plantings with white and pink varieties. Since poinsettias give color from now through March, incorporating plants into the garden design will brighten things up for more than just the holiday season.

Poinsettias will grow on a wide range of soils, including sand, rocky soil and clay as long as the soil is well-drained. In spite of their wide adaptability, the plants will present you a better show of color if you take proper care of them.

In massed beds, fertilizer application is important. An application of fertilizer in August should now be producing large colorful bracts. The plants need repeat applications of plant food in early spring, again in June and perhaps during midsummer if there are heavy rains.

For best results, prune poinsettias back in late winter or early spring after blooming is finished. Cut them back to within 12-18 inches of the ground.

You’ll find a compact plant will furnish more color than a plant with few leggy stalks. To promote a riot of colored bracts, prune the plants several times during the growing season. Nip the new growth tips back after they are 12 inches long, leaving four leaves on each shoot. Be sure to stop the pruning in early September because the flowering buds are set in early October.

Poinsettias show their color according to the day length and temperature. A plant near a lighted window or a street light often refuses to color up like a neighboring plant in a nearby darker corner. Dreary skies in September and early October will shorten the days, causing plants to set buds and flower before the holiday season.

You will find temperature is a limiting factor for a good show of flowers. If night temperatures are much above 70 degrees, bud formation will be retarded. Freak periods of hot weather during this critical time might not permit buds to form at all. The best flower development is when night temperatures range from 60-68 degrees. This year has seen somewhat warmer temperatures at lower elevations retarding flower formation, but upland regions have been ideal for a riot of color.

One problem to watch for now is mite damage. This little almost microscopic eight-legged creature is not an insect. You will need to have a magnifying glass to see it, but the damage is easy to spot. Leaves will have a fine salt and pepper dusty look. Drier conditions are ideal for this pest. Spraying with a miticide will take care of the little stinkers. If you want to avoid sprays, spraying the leaves daily with the garden hose is helpful. This will also minimize whitefly attacks. Avoid sprinkling in the heat of the day or evening to avoid sunburn and fungal diseases.

Poinsettias can be used as cut flowers if the stems are treated to coagulate the milky sap and reduce wilting. As soon as the flowers are cut, immerse the cut ends in hot water for about a minute. Then place them in cold water. Be sure the steaming water does not damage the bracts.

An alternate method of halting the oozing sap is to singe the cut ends of the stem over a flame for a couple of seconds and then place the stems in cold water. For best results and longer lasting beauty, cut the poinsettias about 18 hours before they are to be used in an arrangement. Store the cuttings in a cool, draft-free place during the waiting stage.

If you want to experiment with this year’s potted plant, don’t toss it out when the last leaf drops.

The plant will show brilliant color next Christmas season if you follow these tips.

First, store the pot, plant and all, in an out of the way place. This treatment is intended to induce the plant to hibernate during the cool days while the shriveling top feeds the sleeping roots.

Only water the plant to keep it from getting bone dry. Avoid giving it fertilizer. Try storing the sleeping plant in the shady corner of the carport.

Toward the end of February, tenderly awake the plant by cutting off the dead tips. You can grow the new plant in last season’s pot, but the poinsettia will be happier if you set it in the ground where it can flex its roots better than in the confines of a pot. Make sure you plant it where it will get lots of sun and a well-drained soil.

Cuttings taken from large garden plants of poinsettia and Euphorbia leucocephala in the spring will also root easily to give you a show next Christmas.


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