Ohia Trees (Metrosideros sp)

There are four distinct species of ohia tree that are endemic to Hawaii. In addition to genetic differences, environmental factors will cause physical variations in the trees. Elevation, rain, and temperature all have an effect upon these trees. 

In general, the shapes of leaves from trees growing in hot, dry deserts are often small in order to conserve water loss through the leaf. Contrast this to the large-leafed plants of the tropics. Ohias occur in a wide range of habitats, from just above sea level to 8,200 feet: from dry forests with less than 16 in annual rainfall to wet forests with more than 33 feet of annual rainfall. This along with its genetic propensity for variation will produce trees of diverse appearance. The species name, polymorpha which actually means many forms has eight varieties. Thus tree height and form, leaf shape and flower color are highly variable.

Concerning the care, ohia trees can be damaged and even killed from a lack of water. During periods of drought especially, supplemental watering will be needed. Trees growing in the pahoehoe lava (exhibiting a smooth, billowy, ropy surface) may do well when young and water requirements are low. Nevertheless, as trees increase in size, if adequate water is not supplied, they can dry out and even die.  Mulch will help, but of course, not piled against the trunk.

Since ohias are adapted to grow in low nutrient soils, beware of over-fertilizing. Slow-release fertilizers or natural compost is best. 

Start a Garden

Here are some fundamental points to help along the way: 

·      Plant only as large a garden as you can easily maintain. Don’t over plant and become overwhelmed with the many garden chores: weeding, planting, pest control, soil preparation. 

·      Choose recommended varieties for your region. Midwest and Eastern US seed catalogs, with pictures of giant tomatoes are fine, but those varieties are not necessarily adapted for a tropical climate. University of Hawaii CTAHR seed program develops and sells vegetable seeds suitable for the Hawaiian Islands.  http://www.ctahr.hawaii.edu/seed/

·      Consider locating the garden within easy walking distance to your house in order to carry tools there and eventually return with baskets of produce. 

·      Select a site that receives at least 8 hours of full sun each day.  Plant vegetables where they are not shaded by trees, walls or fences. Nearby trees and shrubs with roots reaching into the garden will compete with the vegetables for water and nutrients.

·      For those with minimal space, grow crops that produce the maximum amount of food for the area available.  You can harvest a lot of radishes, onions, lettuce, bok choy and tomatoes in a small plot.  Plants like pineapple, watermelon and pumpkin squash take up lots of space for what is harvested.  In addition, consider planting vegetables that can be grown vertically instead of horizontally. Vining crops such as tomatoes, squash, cucumbers and pole beans can be trellised or staked to minimize ground space and increase garden productivity.

·      Plant perennial vegetables such as rhubarb and asparagus to one side of the garden so they are not disturbed as you prepare the ground for subsequent annual crops.

·      And finally, try succession planting. A crop like indeterminate tomatoes can be harvested over a long period of time; one planting will last for many months. With other crops like corn, beets and lettuce, the entire crop will mature at approximately the same time. Unless you want to eat all your corn in a short period of time, stagger the plantings at 2-3 week intervals, or more. Read more about growing vegetables by clicking on the column on the right.