Friday | December 15, 2017
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Poinsettia pointers

Dear Garden Guy, I live in Piihonua which, as you know, is very rainy. I have a hapuu garden which has been established for three to four years. Several of my ferns consistently look compromised: yellowish or brownish fronds, few fronds, meager fronds. Some have even developed a miniaturized/malformed type of frond. I fertilize them with chicken manure and compost. I try to keep the floor of the fern garden covered with litter — mostly old fern fronds. I have attached a few photos and hope that you can advise me as to what they may need to be really happy! — Many thanks, J.C.

There are two possibilities for the cause of this problem. One is too much sun. Hapuu grows best in well drained, slightly acid soils with partial shade, but it will tolerate full sun in cloudy, upland areas. In hot sunny lowlands, the plant needs protection from the sun and drying winds.

From studying the pictures you sent, however, the disorder looks like fertilizer or herbicide damage. An overdose of fertilizer can cause frond burn, while drift from herbicides such as RoundUp, can cause new growth to look burned and/or distorted. Mites have also been reported to cause minor damage to Hapuu, but no other insect or disease pests are common to the fern. Chemical damage is the probable cause.

If that is the case, the new growth should return to normal.

Tips for caring for poinsettia plants

For the readers that bought poinsettia plants for the Christmas season, here are some tips for their care once they are taken home.

Unwrap the plant and place in indirect light. Six hours of light daily is ideal.

Poinsettias require daytime temperatures of 60 to 70 degrees and night time temperatures around 55 degrees for best growth. High temperatures will shorten the plant’s life. Move the plant to a cooler room at night, if possible.

Be sure to punch holes in the foil so water can drain into a saucer, discard excess water. Check the soil moisture often. Water when soil is dry.

Fertilize the poinsettia if you keep it past the holiday season. Apply a houseplant fertilizer about once a month. Do not fertilize when it is in bloom.

Though I have discussed the toxicity of poinsettias in past years, it bears repeating since the question comes up annually. Ingestion of the poinsettia plant has been found to produce no effect except an occasional case of vomiting. No deaths resulting from poinsettia ingestion have ever been documented. Once again here are the facts: according to the POISINDEX information source, a child who weighed 50 pounds would have to eat more than 500 poinsettia leaves in order to reach a potentially toxic dose of compounds in the poinsettia plant. Since the taste of poinsettia leaves is reportedly very unpleasant, it is unlikely that a child or animal who attempts to eat or chew the leaves will continue to do so after the first taste. Some people, however, may develop a skin and eye irritation from contact with the milky sap of the plant.

I’m a little confused, with all this talk about native species. Can you define native species for me? And what is an endemic species? Mahalo. — R.M.

Native plant species are those that originated in a given geographic area without human involvement; that is, by natural process. In Hawaii, it is said that native species are those that have come here on the waves, by the wind or on some wings. The word indigenous is also used.

A species can be indigenous to more than one location.

If a plant is listed as endemic to a certain region, it means that this is the only area where it is native; it occurs naturally only in that place.

Hilo resident Nick Sakovich is a professor emeritus of the University of California. He has worked in the field of agriculture for 30 years. Email your questions to Sakovich at


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