A Question of Invasiveness

By Ken Love

Feb. 11,2004


There is a question of invasiveness regarding some of the choices for fruit in the 12 trees project. In a poll of Big Island chefs four fruit types they choose are on various invasive lists, including their number one choice of Mysore raspberry. This can be addressed in a number of ways. With a balance of proper horticulture, effective marketing and protective fruit wraps, invasiveness should not be an issue. A brief outline of the fruit and horticultural procedures for its production follows.


The species in question are:


Botanic name               Common Name           Hawaiian Name


1.         Psidium cattleianum   Strawberry guava         waiawi

2.         Physalis peruviana       Cape gooseberry         poha

3.         Rubis nieveus              Mysore raspberry        --

4.         Eriobotrya japonica     Loquat                         --



Strawberry guava


Native to Brazil, strawberry guava is thought to have been introduced to Hawaii in 1825 by the British voyaging ship Blonde. Invasive references mention the fruit as problematic in moist and wet rainforest areas. In Kona, especially the lower elevations, there are very few trees. Those that exist are cultivated in home gardens. In some cases they seldom fruit for lack of rainfall or immature fruit will abort.  In South Kona starting at the 1200-foot elevation the trees will fruit in years where there is a significant amount of rainfall. There has been no significant amount fruit on wild or cultivated trees (without irrigation) in the past 16 months. Previously these trees have produced a fair amount of fruit, larger when the trees are shaded or when the fruit is thinned. These are what chefs have expressed an interest in. In order to provide culinary quality, the fruit must be grown in protective bags

(http://www.hawaiifruit.net/bags.htm)  to prevent birds, fruit flies and other pests from attacking it. Trees are kept at a height, which is conducive to bagging and harvesting without the use of ladders or picking devices.


In a marketing test a few years ago, approximately 60 pounds a week here harvested and sold at a local store in Captain Cook. Other samples were sent to chefs where the fruit was used on the buffet line and with in-room amenity baskets at hotels. With a current working price of $2.00 per pound, we are unable to purchase enough fruit for further marketing tests with hotels or groceries. As the trees in South Kona did not flower last year, further tests will have to wait. 


The fruit is spread by seeds that are prolific but not viable for long periods of time.

As all fruit for culinary purposes is grown in protective bags, fruit from trees planted as part of the 12 trees project would be contained. A growing guide for strawberry guava would warn of the potential for invasiveness in moist areas and encourage the use of protective wraps. It would also encourage fruit thinning and potentially the harvest of fruit from wild but public areas thus decreasing possible future invasiveness.



There are 2910 references to “Strawberry guava in Hawaii” on Google.








Weeds of Hawaii’s Pastures and Natural Areas by Philip Motooka et al.



Cape gooseberry or Poha


Native to Peru, Chiles and Brazil, the poha is generally thought to be naturalized in Hawaii from 1000 to 6000 foot elevations in mesic to wet forest areas. Thought to have arrived in Hawaii prior to 1825, it has been cultivated with some success. The fruit is popular to the point where CTAHR has published a Horticultural fact sheet and propagation guide. In 1966 the university worked to develop equipment for husking poha. A quick poll of 20 restaurants, both free standing and in hotels, revealed that all but 2 use poha in some of their dishes. Many of the Internet searches feature Hawaiian products with poha.


Poha has been included in the “other” category in the Hawaii Agriculture Statistics Service fruit survey signifying that there is a marketed production. In the newly issued survey, poha has earned its own category.


In January and February of 2004 both state and USDA inspectors checked shipments of poha coming into Hawaii from outside the state showing that the demand for the fruit is growing. The working retail price is $7. Per pound. Yield per plant is 300 berries or just over 2 pounds per bush. With recommended spacing, an acre of poha can yield 3000 pounds of fruit in the course of a season.


In order to achieve a maximum yield, poha is generally checked daily during harvest season in order to prevent insect damage once the husk has fallen. As the bush is seldom over four feet in height, it is easily trellised and can be netted to prevent bird damage.



There are 470 references to “Poha in Hawaii” on Google.







Weeds of Hawaii’s Pastures and Natural Areas by Philip Motooka et al.



Mysore raspberry


Native to India and Burma, the berry was said to be introduced to Hawaii in the 1880s.

It is listed as noxious for a number of areas that the state identifies. “Risk areas are moist and wet forests from almost sea level to 7000 foot elevation” Areas identified in much of the reference material below, refer to elevations above the 2000 foot level where there is significant rainfall. The 12 trees project site is at about 300 foot elevation in a dry area. Irrigation would be required for the plants.


In the newly issued Hawaii Agriculture Statistics Service survey, Mysore berry has earned its own category.


The fruit was the number one choice of Big Island chefs polled as part of the 12 trees project. http://www.hawaiifruit.net/12trees.html  .The working price is $7.00 per pound with 3000 fruit or about 13 pounds per cane grouping. Over the past 8 years we’ve worked extensively with 2 cane groups that have not spread at all in a 10 acre area.

Cultivated in many countries and parts of the US, including Kona, the berry can be controlled with proper horticulture, pruning and harvesting. Weekly pruning prevents the thorny cane shoots from becoming out of control. Harvesting every few days prevents animal destruction of ripe fruit. At one Kona site, the plant is trellised and cut back twice yearly. With pruning, plants can be shaped and kept at a three to four foot height making it possible to net or place a screened box around the canes.  For the purpose of yield, trellising seems to be more effective.  This combined with aggressive pruning of shoots can prevent invasiveness.



There are 1280 references to “Mysore berry in Hawaii” on Google.










Weeds of Hawaii’s Pastures and Natural Areas by Philip Motooka et al.



Indigenous to Southern China, the loquat was first thought to have entered Hawaii with early Chinese immigrants in the 1870s.

The state has identified risk areas as moist and wet areas up to 5000 foot elevation.  Said to be spread by birds and animals, the loquat can easily be contained with proper horticulture by using examples set in Spain, China and Japan. They are the largest commercial producers of the fruit. In China and Japan the fruit is thinned in the green stage then wrapped in protective bag until harvest.  This insures the fruit is pest free and has no bird damage. Trees are kept at a two to three meter height to facilitate wrapping and harvesting of fruit.


Loquat has been included in the “other” category in the Hawaii Agriculture Statistics Service fruit survey signifying that there is a marketed production. In the newly issued survey, loquat has earned its own category.


Arguably one of the most popular fruits in the world, the loquat is virtually unknown in the U.S. It represents a considerable market potential for Hawaii as our harvest time is months ahead of other locations where the fruit is very popular. The potential for marketing in Japan is being investigated although no request for a pest risk assessment has been submitted. At present, there is not enough commercial production to warrant the request. Japan’s production begins in late March and peaks in May while in Hawaii harvest begins in late November with peaks in January. Multiple flowering and fruiting is fairly common although not regular without irrigation. Hawaii could provide the fruit for the New Year gift giving season in Japan once production and quality standards are established. The market potential in Japan would be assessed at a multi-million dollar level.


With current production estimated at 2000 pounds and priced at $2.50 to $3.50 a pound,

The extent of distribution has been limited to hotels, a few local groceries in Kona and farm stands.  Demand by hotels alone far exceeds production with additional requests for quantity of fruit from other islands and wholesalers.


The Big Island chefs choose loquat as the third most requested fruit they would like to work with, following the Mysore berry and figs. It is one of he world’s oldest cultivated fruits with an estimated 900 named varieties. Most parts of the plant have some use. The leaves have been used in tea for thousands of years in China where loquat herbal cough medicine is also common. New varieties that have passed the USDA quarantine period are expected to help create new opportunities for Big Island farmers.



There are 17 references to “Loquat invasiveness in Hawaii” on Google.

There are 9360 references to “Loquat in Hawaii” on Google.















Weeds of Hawaii’s Pastures and Natural Areas by Philip Motooka et al.





Although there is always a chance that fruit from cultivated fruit trees can “escape” into the wild, the issue can be addressed with proper horticulture.  Following the examples set in Asia, protective fruit wrapping is essential for fruit quality and consistency regardless of the invasiveness.  Frequent harvesting for freshness is another key to the success of building markets for unusual fruit.


The goals of the 12 Trees Project are to promote sustainable agriculture while providing positive economic alternatives for farmers. This, combined with the simultaneously building of production and markets for 12 types of fruit chosen by chefs, will help to enhance rural economic development for farmers and fruit growers.