Tuesday | April 21, 2015
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Tips for helping your Hawaiian sandalwood trees survive

Recently I purchased two Hawaiian sandalwood seedlings, Santalum ellipticum. I was told that due to the sandalwood’s symbiotic relationship with nearby plants, these sandalwood plants must be interplanted with other host plants in order to survive. The idea being to mimic as closely as possible the sandalwood’s natural growing situation.

Can you suggest any ideal candidate plants, other trees and perennials that would serve the needs of the Hawaiian Sandalwood tree? Thank you for all the knowledge you share with the people of Big Island in order to make Big Island a better place to live. Kind Regards, M.W.

Sandalwood trees (Santalum sp.) are classified as hemi-parasites. The term describes a plant that is green and can produce its own food but also derives water and some nutrients by attaching to the roots of other plants. This can effectively join together whole plant communities through their root systems. The plants that donate nutrients to sandalwood are called hosts; sandalwood trees do not grow well without a host. In fact, this ‘intercropping’ is not only possible but necessary; they need to be grown with other suitable host species.

According to the publication, “Species Profiles For Pacific Island Agroforestry,” which can be accessed on the CTAHR website,” S. ellipticum, one of four species known as Hawaiian sandalwood, can “successfully develop into relatively large individuals when growing with endemic species such as Wikstroemia sandwicensis (‘akia) and a fan palm Pritchardia remota (loulu) in windward, lowland areas.

In more xeric (dry) environments it has developed successfully in association with the endemic shrub Chenopodium oahuense (‘aheahea) and Chamaesyce hypericifolia. Apparently S. ellipticum, is flexible in the species it can parasitize for needed nutrients.”

S. ellipticum is endemic to the Hawaiian Islands. It is found as a sprawling to bushy shrub near the ocean shore. It is occasionally found as a larger shrub to small tree in dry gulches, on slopes, and frequently in rocky habitats. S. ellipticum is adapted to arid habitats with typical summer drought in leeward lowland locations.

Hawaiian sandalwood species generally resist most insect attack; sometimes infestations of whitefly or scale insects can be found. Insecticidal soap may be used to treat such infestations. Slugs and snails will also feed on newly sprouted plants. The trees generally tolerate a broad range of soil conditions but show a preference for well drained neutral to slightly alkaline soils. Since many Hawaiian soils tend to be acidic, an application of lime would be appropriate to bring the soil closer to neutral.

The wood of the Sandalwood trees is often used for carving handicrafts, art, musical instruments and decorative furniture.

My bell pepper plants aren’t growing well. The leaves look good, but I can’t get the flowers to stay on and produce fruit. It’s either the flower or small fruit that’s always dropping. What’s going on? A.W.

Flower and fruit drop of bell peppers is caused by the pepper weevil. The mature black weevils or small white worms, the weevil larvae, can often be seen when the fallen fruit is cut open. Holes are made in the young pepper and in flower buds by the feeding of adult weevils, by females laying eggs or by emerging adults. Infested peppers that do not rot and fall will have blackened seeds and cores as a result of larval feeding. Mature peppers are not susceptible to weevil attack, because the skin is usually too hard.

Sanitation is very important in controlling this pest. Remove all peppers that have dropped to the ground. For the next planting, rotate to another non-solanaceous crop, do not plant tomatoes or eggplant; control solanaceaous weeds. If weevil numbers build up and are causing major damage to the crop, there are registered pesticides available such as carbaryl (sevin). Pyrethrin may be acceptable for use on organically certified produce.

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 askthegarden guy@earthlink.net. You also can visit his website at www.gardenguyhawaii.com.


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