Basil - a Great Aromatic Herb

Basil is a member of the mint family and is one of the world’s most popular herbs.   In colder climates it is generally grown as an annual, but in Hawai`i   can be grown as a perennial.  After flowering, when seeds have matured, basils will stop producing new leaves.  To ensure continued growth, cut off any flower buds that begin to form. Be sure to cut the branch rather than just the tips, otherwise, new flower buds will quickly appear.  By pruning basil often (every 3-4 weeks), plans remain vigorous with many harvests throughout the season. 

Sweet basil is the variety most widely grown on the Islands, but there is also Thai basil, lemon basil, cinnamon basil and royal basil.  Basil prefers a sunny location with a well-drained soil.  Typically, the best time to harvest basil is in the morning when the essential oils are strongest. However, University of Michigan researchers have found that harvesting basil in the evening between 6 and 10 p.m. increases its shelf life.

This aromatic herb can be used in soups, stews, and rice dishes, and with fish, chicken, and other meat. It can also be a key ingredient in cheeses, vinegars, oils, jellies and teas.  Even basil's flowers are edible and can be candied or added to salads and other dishes. For optimum flavor, add fresh basil in the last few minutes of cooking; the dried spice just doesn’t have the same robust flavor as the fresh.

Cooks often notice that fresh basil will quickly turn black.  This is due to oxidation of some elements in the leaves. To prevent this blackening and insure the best flavor, add basil to salads and other cold dishes soon after cutting. 

Pests – Basil is often grown with few or no pests.  But some of the more common problems encountered are thrips, leafhoppers, whitefly, spittlebug, scale and leafminers.  Insect pests that would be causing chewing damage to the leaves include the Chinese rose beetle, beet armyworm, a pinkwinged grasshopper and flea beetles.  If you see worms (caterpillars), pick them off, or you can spray the plant with an insecticide with the active ingredient, Bacillus Thuringiensis (Dipel, Javelin). Bt is an organic, bacterial preparation which will control the caterpillar but is harmless to humans.  

Hapuu, the Hawaiian Tree Fern, vs. the Australian Tree Fern

                                                        
The Hawaiian tree fern is native to most of the Hawaiian Islands. Although once common, hapu’u stands have been reduced due to a large number of ferns being harvested for orchid media and landscape use. The last remaining large stands of native hapu’u are found on the Big Island.

The Hawaiian hapu’u  are very slow growing; the young ones grow at about 3.5 inches per year while the older plants grow even more slowly, eventually growing to  15-20 feet tall.  The unfurled fronds are covered with silky, red-brown wool-like fibers called pulu.  In the past, pulu was used for stuffing pillows and mattresses and for dressing wounds.

The Hawaiian tree ferns are relatively easy to grow. They grow best in well drained slightly acid soils and partial shade; they will tolerate full sun in cloudy upland areas. They need a steady supply of water and occasional light applications of a complete, slow release fertilizer. Old and injured fronds should be pruned. It is illegal to ship tree ferns or products from the ferns internationally. 

 The Australian tree fern, Cyathea cooperi, is considered invasive in the State of Hawaii due to aggressively out competing native plants in the forest understory. As a threat to  Hawaiian forests, this fern eventually displaces the native ferns, including the slower growing Hawaiian tree fern, or hapu’u.  


Although invasive, the Australian tree fern is being sold in Hawaii at many commercial plant nurseries. This fern grows to 40 feet tall and tolerates full sun in cool wet areas. The spores are spread by wind and can travel over 7 miles from the parent plant.

 The best diagnostic characteristic to distinguish between the Australian tree fern and the native hapu'u is the hairs on the leaf stems. With the  hapu’u, the hairs are either fine and reddish-brown for hapu'u pulu (Cibotium glaucum) or fine and black for hapu'u i'i (C. menziesii). The hairs on the Australian tree fern are broad and white.
     

                                                Cibotium menziessi

  Photos: Native Plants Hawaii, University of Hawaii

Bugs - the Good, the Bad and the Ugly

Not all bugs in the garden are bad. 
Some bugs are beneficial. such as parasites and predators. The are looking for pests to consume. Two well-known good guys are preying mantis and lady bird beetles; spiders are also good predators.  Biological control can work very well. As an example, in California when certain species of whitefly came into a new area, both citrus  and some vegetable crops were damaged or completely destroyed. Yet within a number of years, their natural enemies were established, and for the most part, the pest became inconsequential.  Pollinating insect can also be categorized as beneficial.

Some bugs may be found on a plant, but are not feeding and therefore cause no damage. The bug may simply be resting or perhaps searching for nectar or another source of food.                                                                                                   

               
Some insects of course are known pests, but cause little damage. A bite may be taken from a leaf here and there,  or a little juice sucked from a stem, but overall, the plant is not harmed. 
On the other hand, some bugs do inflict damage, but it is only cosmetic. That is, the leaves or fruit may be scared or misshapen, but there is no real loss of yield.  In many cases, cosmetic damage should be tolerated. This type of damage on citrus fruit is caused by thrips and does not affect the internal quality.    

Above Photos: University of California IPM Program

And finally, if there is an infestation of an insect pest which will cause yields to be significantly lowered, the gardener will have to decide whether to wait a bit and see if biological control will work. If a parasite or predator can control the pest population, no intervention is needed. Yet if spraying is the choice, consider first a bio-rational pesticide, such as soap, oil, Bt or sulfur. These are less injurious to the environment, and may not harm the predator or parasite populations. 

And, the Ugly

Arizona State University