Pineapples - Easily Propagated

Can the top of the pineapple fruit be cut off and planted in order to produce a new plant? The answer is YES! There are many variations on how to propagate pineapple. The drier the environment, the more precise the instructions need to be followed. In Hawaii, especially in high rainfall areas, propagating pineapple is relatively easy. 
  

The simplest method is to cut off the top of the pineapple, called the crown, as you normally would do when cutting the fruit. Let the top sit in a shaded, dry area for 2-7 days. Before planting, remove the dried fruity portion and some of the lower leaves exposing  ½ -1 inch of the stem. Letting the crown sit for several days will seal the wound and make it less susceptible to rot. When planting, keep in mind that the mature plant can grow to 3-4 feet in diameter and height. Mature plants also have a tendency to fall over, thus planting several together, they will give each other support.

Alternatively, the stem can be placed in a shallow glass of water. Be careful to place only the stem and not the leaves in the water.  After a short time, roots will form; it is then ready to be planted outside.  

Plant a Rainbow of Colors in Your Garden

When planting a vegetable garden, let color be your guide to healthy eating.  For a number of years, scientists have been discovering the health benefits of the color pigments in food.  For some gardeners, a vegetable garden is lettuce, collard, mustard greens and kale- all healthy, leafy green vegetables.   But for health sake, add some color such as red tomatoes, yellow squash and purple eggplant.  Grow a rainbow of colors to the garden for good health.

Red colored fruits and vegetables contain natural plant pigments called lycopenes or anthocyanins. These compounds may help reduce the risk of several types of cancer, especially prostate cancer. By the way, the lycopenes in cooked tomatoes with a small amount of fat are absorbed better than lycopene from raw tomatoes.  Sun dried tomatoes are reported to have twelve times the lycopenes as raw ones. So plant plenty of tomatoes, beets, watermelon and red peppers. If there is room in the garden, include a pigmented citrus tree like pink grapefruit. 

Orange and yellow colors come from natural plant pigments called carotenoids.  Beta-carotene is converted to vitamin A which helps maintain healthy eyes.  Carotenoid-rich foods can reduce the risk of cancer, heart disease and improve the immune system function.  Plant plenty of yellow sweet potatoes, squash, pumpkins and carrots.  Citrus contains hesperidin, also found in the skin of tomatoes, and naringenin, which are anti-inflammatory and antioxidant. Curcumin, found in turmeric, known in Hawaiian as olena, has antioxidant properties. Turmeric is a popular Indian spice used in curries and other dishes.  Anecdotal evidence suggests that turmeric can be used to deter ants in the garden.

Other yellow and orange fruits grown in Hawai`i are pineapples, papayas and mangos. Pineapples contain bromelain, an enzyme which aids digestion.  Papaya and tangerines contain beta-cryptoxanthin, another carotenoid, playing an important role in vision and in bone growth. Papayas can easily be grown from seeds or purchased in abundance at local markets.

 Greens are colored by a natural plant pigment called chlorophyll.  Some greens contain lutein which helps keep eyes healthy. Here is a familiar list of green vegetables: green peppers, peas, parsley, watercress, arugula, spinach and kale.  Crucifers like broccoli and cabbage contain chemicals which may help protect against some types of cancer.  Leafy greens such as spinach and broccoli are excellent sources of folate, which is a B vitamin. 

The blue and purple colored fruits and vegetables also contain pigments called anthocyanins, powerful anti-oxidants which improve brain function and help to reduce the risk of cancer, stroke and heart disease.  Fig trees grow well in tropical and sub-tropical climates and should yield delicious, healthy fruit.  Anthocyanins, also found in strawberries and raspberries, act as powerful antioxidants that protect cells from damage. 

The whites contain pigments called anthoxanthins which are shades of white or yellow.   This group consists of onions, garlic, cauliflower, turnips, mushrooms, potatoes and bananas.  At least one of the group, garlic, contains a health-promoting chemical called allicin. This compound may help lower cholesterol and blood pressure and help reduce the risk of stomach cancer and heart disease. Potatoes, as well as bananas, are good sources of potassium. 

Why fruit trees don’t produce.

Since there are many factors involved in fruit production, there are also many reasons why fruit trees don’t produce.  Here are a few of the more common ones.

·        Rain- Too much rain during the bloom period can wash pollen away,  and a forceful rain along with wind can actually knock blossoms off.  Also, bees tend to fly less, or not at all, during heavy rains.

·        High heat and low humidity during bloom will hamper pollination.

·        Juvenility  - Sometimes it takes many years before a tree will produce fruit; mangosteen is a good example. However, new evidence indicates the size of the tree is more of a factor than age. In general, trees grown from seed take longer to produce fruit than those that are grafted, budded, or air layered. 

·        Pollinators – Some fruit trees require more than one tree or one variety in order to set more abundant fruit.  Examples are rambutan, macadamia, and avocados.

·        Some trees require insects to help in pollination, such as durian. 

·        Lychee and longan need a combination of low temperatures, 50 -59 degrees Fahrenheit, and a dry period (4-6 weeks) before bloom occurs.  Bloom for rambutan will be enhanced in response to drought.

·        The deciduous fruit trees, like peach, plum, nectarine, apple, etc., require cooler temperatures for good fruit production. This chilling requirement is the number of hours the tree needs to experience below 45 degrees F.  This requirement differs among species and varieties, ranging from a few hundred hours to over a thousand. 

Passionfruit - Hawaii’s Favorite Flavor

The yellow passionfruit, Passiflora edulis f. flavicarpa, and the purple passionfruit, Passiflora edulis, are grown in most tropical and subtropical parts of the world. The yellow passionfruit is a tropical plant while the purple is considered subtropical, being able to survive some freezing temperatures.

Of the hundreds of species in the genus Passiflora, these two, P. edulis, and P. edulis f. flavicarpa, are solely designated as passionfruit.  In Hawaiian, the fruit is called lilikoi and in Portuguese, maracuja peroba.  When the seeds of purple passionfruit first came to Hawai`i from Australia in 1880, they were planted in East Maui in the District of Lilikoi and that name stayed with the fruit. The seeds of the yellow passionfruit were brought to Hawai`i from Australia in 1923. 

In 1951, there were only a few acres of passionfruit plantings. It was then that the University of Hawai`i chose passionfruit as the most promising crop for development. And by 1958, there were 1,200 acres of primarily yellow passionfruit, and the industry was firmly established.

The lilikoi vine is a shallow rooted perennial, displaying beautiful, fragrant flowers, 2-3 inches wide. The fruit is nearly round approximately 1 ½ - 3 inches wide.  Inside, the fruit is filled with an aromatic mass of juicy pulp and within are as many as 250 small, edible seeds.  These vines, especially the yellow, are fast-growing and will begin to bear in 1 to 3 years. In fact, some vines can flower and fruit within a year after being started from seed. In Hawai`i, passionfruit matures from June through January; the ripe fruit will fall to the ground.

Carpenter bees are efficient pollinators for the yellow passionfruit. Honey bees and the hover fly also help in pollinating but are much less efficient. Wind is ineffective as a pollinator because of the heaviness and stickiness of the pollen.

The yellow lilikoi vine tends to be more vigorous and the fruit generally larger than the purple. While the purple appears to grow better at higher elevations, 400 to 3,000 feet, the yellow fruit is best adapted to lower elevations, from sea level to 1,500 feet. Furthermore, the yellow will yield 3 to 4 times that of the purple, yet the purple fruit is considered to have better flavor and aroma with the pulp being less acid with a higher proportion of juice.

Passionfruit vines are usually grown from seeds.  If the seeds are planted soon after being removed from mature fruit, most will germinate in 2 to 3 weeks. Fortunately, seeds do not require cleaning, drying or storage. They can be planted immediately after being removed from the fruit, even separation from the pulp is not necessary. In fact, allowing the pulp to ferment for a few days may hasten germination. In contrast, seeds that have been cleaned and stored actually have a lower and slower rate of germination. 

Propagation of passionfruit can also be accomplished through air layering and cuttings. Good soil drainage is essential for successful plantings.

Commercially, vines are trained on wire trellises. For backyard production, however, the yellow passionfruit is more productive and less subject to pests and diseases if allowed to climb a tall tree.

In Hawai`i, Oriental and melon fruitflies will deposit eggs in young fruit. This may cause fruit to shrivel and fall from the vine. If older fruit is pierced, the only ill effects will be an external scar. Other pests include aphids, scale, thrips and mites. In spite of all these, passionfruit or lillikoi vines flourish on fences and in trees, in backyards and vacant lots around the Islands.

The juice with its distinct flavor and aromatic bouquet is a key ingredient in making sauce, candy, ice cream, sherbet,  iced tea, or in cocktails.  In the Hawaiian Islands lillikoi is a favorite flavor enjoyed by young and old alike. 

Photos  by Forest and Kim Starr

Bananas – A Fruit for All Reasons

There truly seems to be ample evidence that bananas are more than just a good source of potassium. Nutrients such as vitamin A, vitamin C, vitamin B6 and niacin, as well as the minerals phosphorous, calcium, magnesium and manganese are all present in bananas. In addition, no fruit is higher in energy value except the avocado. This is because the banana has three natural sugars -sucrose, fructose and glucose which give a substantial boost of energy. Other benefits of bananas are as follows:         Help fight depression. They contain tryptophan, which converts into serotonin, a chemical known to make you relax and improve your mood. For this reason, bananas can also help sufferers of Seasonal Affective Disorder (SAD).         High in iron. Bananas can stimulate the production of hemoglobin in  the blood and so helps in cases of anemia.         Reduces the risk of high blood pressure and stroke. Bananas are extremely high in potassium yet low in salt. The US Food and Drug Administration allows the banana industry to make official claims for the fruit's ability to reduce the risk of blood pressure and stroke.  According to research in “The New England Journal of Medicine”, eating bananas as part of a regular diet can cut the risk of death by strokes by as much as 40%.         Research has shown that the fruit can assist learning by making pupils more alert.         Bananas have a natural antacid effect in the body so if you suffer from heartburn, eat a banana for soothing relief.         Some people even rub mosquito bites with the inside of a banana skin to reduce swelling and irritation.         Bananas can also help people who try to give up smoking. It seems the B vitamins, along with potassium and magnesium found in bananas help the body recover from the effects of nicotine withdrawal.

Tropical Favorites

Some favorite tropical fruits, spices and flowers all belong to the same plant order known as the Zingiberales. They include banana, ginger, cardamom, turmeric and the beautiful heliconia flowers.

Banana, sometimes referred to as a tree or palm, is actually an herbaceous plant since the trunk or stems do not contain lignin. Lignin is the substance that makes wood, woody.  

Ginger originates from Southeast Asia and is unknown in the wild but has been cultivated since ancient times. Ginger was introduced into Europe from China and introduced into Mexico and the Caribbean by the Spaniards. Today it is widely used in local medicines in India and the Far East. China and India are the largest producers of ginger.   

Cardamom is native to India. The dried fruits are used in medicine and as a spice.  Cardamom seeds, which have a pleasant aroma, are used in curries and breads.   

Turmeric, or olena as it is called in the Hawaiian language, comes from the root of Curcuma domestica; it is an important ingredient in curry powders.  Turmeric has been gaining recognition as an anti-inflammatory herbal remedy. Preliminary findings suggest that a chemical found in turmeric called curcumin may have carcinogenic retarding properties but these findings have not been confirmed. With its bright yellow color, turmeric is also used as a fabric dye. This species is unknown in the wild; it is sterile and does not produce fruit. Turmeric is also known as Indian saffron. 

Lastly, in the plant order Zingiberales there are over 100 different species of heliconia flowers.  They produce some of the most beautiful and commercially important flowers for both potted plants and bouquets. Heliconias require high temperatures, humidity and light intensity.  In the wild they grow mainly in forest clearings. The Bird of Paradise, which is the national flower of South Africa, is also in this group. 

Avocados: Bountiful Blooms, Few Fruit

 Avocado, as well as citrus trees, produce an abundance of bloom. But only a fraction of those flowers remain to produce fruit. Furthermore, after the fruit is set, some premature fruit drop will occur; it is the natural thinning process.  

Yet any stress occurring during the time of bloom and young fruit development, will cause additional fruit drop.  These stresses include too much water, not enough water, nutrient deficiencies, vog (volcano emissions), and a few days of sudden high temperatures. Heavy rains during the bloom period can also contribute to low or no fruit set. Since pollination is principally by bees, a lack of them will also add to poor fruit set. 

In addition, avocado trees are categorized according to their flower type, either “A” type or “B” type flowers.  When only trees of the same flower type are planted together, they will produce fruit. However, when the opposite flower type is planted nearby, production is increased.  Having both flower types in a commercial orchard is important. In a neighborhood setting, a high probability exists that a tree with an opposite flower type will be in the area. Also note that avocados will produce a heavy set of fruit one year and usually rest the next by producing a lighter set.

If trees are a grafted variety, they should begin to produce in three to four years, while avocado seedlings (non-grafted) will take much longer to produce, perhaps seven to ten years.    

Avocados and Clay Soils Don't Mix

Avocado trees, planted in a clay soil in an area of high rainfall, will frequently be unhealthy. Various species of trees can tolerate ‘wet feet’ such as the great magnolias of the South which grow in the swamps. Other trees, like avocado and citrus, do not like to sit in water. In order for most trees to thrive in places of high rainfall, they must either be able to tolerate lots of water or be grown in well-drained soils. Unfortunately, a clay soil does not facilitate good drainage.

A key element to remember is that roots need oxygen as much as they need water. When it rains, water fills the air pockets in the soil. For good plant health, a portion of that water needs to quickly drain away to allow the air to come back. In clay soils this does not happen; the clay holds onto the water.  

In arid climates, farmers who have clay soils simply apply water less often. In tropical climates, the clay soil has little or no chance to dry out; oxygen is excluded, and the roots die. In the case of avocados, it has been shown that after 72 hours in a water logged soil, their roots begin to decline.  Once this happens, leaves turn yellow and drop resulting in twig and small branch dieback.

Clay and rain are a bad combination for many plants. There is not much to be done for existing trees; the soil can’t be changed neither can the rain be stopped. A good recommendation is to plant on a slope where there is better drainage. Sometimes trees can be planted on mounds about 3 feet high. It won’t do any good to dig a hole, put the tree in and fill the hole with a different type of soil. That is like putting sand in a bathtub, plugging the drain and planting a tree in it.

Dragon Fruit

Dragon fruit is produced from a climbing cactus plant known as pitaya or pitahaya; the fruit is also called pitaya. In Hawaiian it is known as paniniokapunahou or papipi pua. A famous hedge of pitaya, with its triangular fleshy stems, is growing at Punahou School on O`ahu. From July to October the hedge blooms with a wall of white flowers hundreds of yards long. This type is considered an ornamental that occasionally bears a few small, red fruits. Like many species of pitaya, it is self-sterile, that is, a plant not capable of reproducing with its own pollen. Recent breeding programs in Taiwan and Vietnam have resulted in the development of many self-fertile and productive pitaya varieties.

Since the pitaya plant blooms only at night, when many insect pollinators are not active, successful pollination is sometimes difficult to achieve for adequate fruit bearing.  Moths and bats are the likely pollinators for pitaya plants.  If moth and bat populations are low, pollination will be limited; some backyard enthusiasts have resorted to hand pollination.

To help with pollination, gardeners can turn outside lights on in order to attract moths in the evening during the bloom period.  Heavy rainfall during this time, would cause a lack of moth flights, and therefore, poor fruit production. For good fruit production, it is important to choose the right variety.

Dragon fruit plants prefer a warm, moist climate with rich organic soil. It is not suitable for areas with extreme high temperatures and intense sunlight. The plant will tol­erate short exposures to freezing temperature and will re­cover rapidly. It requires 25-50 inches of rainfall annually. Excessive rain can cause flower drop and the fruit to rot. Commercial plantings of pitaya can be found in Vietnam, Taiwan, Malaysia and Israel. 

Above photos by Forest and Kim Starr 

                                                              University of California Cooperative Extension