Friday, October 20, 2017

The Beautiful Vireya

Vireya are part of the rhododendron family, classified as a subgenus. They are native to Southeastern Asia - New Guinea, Borneo, Sumatra and the Philippines, growing quite often in the cooler mountainous areas. On the Big Island of Hawaii, vireya, also called tropical rhododendrons, are successfully grown from Volcano down to the coast.  There are about 300 species of vireya. Azaleas are part of this group.
Vireya grow well in the sun.  Yet locations of intense sunlight along with high afternoon temperatures should be avoided. In this case filtered sun is best. On the other hand, planting vireya in the shade will produce leggy shrubs with inferior flower production. No hot summer sun, no heavy shade.
It is important to plant vireya in soils and potting mixes that have excellent drainage. In addition to growing them in the soil, and sometimes in cracks and crevices, they can also be found growing as epiphytes. An epiphyte is a plant that grows upon another plant such as a tree, but is not a parasite on that tree.  The epiphyte derives its moisture and nutrients from the air and rain and sometimes from debris accumulating around it.
Vireya are well adapted for growing in pots and may even grow well indoors in a well-lit room. They come in a variety of beautiful, vibrant colors such as salmon, pinks, orange and yellows.

For those interested in learning more about vireya, join the Hawaii Chapter of the American Rhododendron Society or search to see if there is a chapter in your area.


Wednesday, September 20, 2017

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.  


Thursday, September 7, 2017

Japanese Maple in the Tropics



Being a deciduous tree, the Japanese maple is indeed adapted for cold climates. Hawaii, as well as other tropical locations, does not provide the best growing environment; yet the trees will grow in these areas. I have one Japanese maple that is now 9 years old. Admittedly, it is not the most vigorous tree, and I think it is continually looking for winter. Sometimes it goes dormant in spring or even in the middle of summer, but it still grows. A question might be, how many years can it survive without experiencing a dormant period?

There are over 1000 cultivars of Japanese maple. Obviously some will adapt to tropical regions better than others. Usually, nurseries select those varieties best suited for their area.

Regardless of the climate, another problem is an insect called Chinese rose beetle. This beetle makes holes in the leaves weakening the tree. 

In the evening, when beetles are feeding, placing a cover or netting over the small trees will exclude the pest. Another choice for control is to use a systemic insecticide with the active ingredient imidacloprid. Granules can be applied to the pots and watered in. 

On this website, gardenguyhawaii.com I have a detailed report on this pest; search Chinese rose beetle in the space on the left of the screen.