Editorial

And so another year of gardening begins! No news this time around, given the lengthy feature article. It's about a group of plants most readers have probably never considered growing, even if they can. Until next time, Aloha!

Queensland Garden Events 2016

A reminder to Queensland residents organising public garden-related events this year: send your dates in for free promotion at www.calyx.com.au/eventsdiary.html. Additional details such as guest speakers and other attractions can be added closer to the event if these are yet to be finalised. Meanwhile, it gives potential visitors a chance to mark their calenders and plan their trips. Don't forget a link to your website can be included, if you have one.

Dwarf coconut variety Malayan Red Dwarf growing in Malaysia (Image "Under A Healthy Malayan Red Dwarf Coconut Tree!" by Jason Thien licensed under CC BY 2.0. Cropped & exp. adjusted from original)

Feature Article

Dwarf Coconuts

Few species are as well known and easily recognised as the coconut palm (Cocos nucifera) irrespective of where you live in the world. No plant is more evocative of the tropics. You probably also know that this plant has a myriad of uses as food, construction materials and the production of other useful goods.

However, you may be surprised to learn that distinct varieties of coconut have arisen in various parts of the world, including many dwarf strains. These have many advantages over the "talls" in large scale cropping, home food gardens and ornamental planting.

Size and form

Within the broad "dwarf" grouping are many varieties exhibiting a range of growth rates, husk colour, fruit qualities and other characteristics.

The dwarfs' main distinguishing characteristic is, of course, their size. While talls typically grow 20-30 metres, dwarfs typically will take 20 years to reach 8-10 m. Dwarf trees produce smaller nuts, but more prolifically [1, 2, 3].

While caution still must be exercised with respect to placement, with dwarfs the risk of serious injury from falling nuts is reduced. During the early years of bearing, nuts form below head height and even more mature specimens will be easier to harvest with domestic equipment.

Furthermore, these trees are more in scale with urban landscapes and the bold, tropical-look foliage can be appreciated better near eye level. 'Fiji Dwarf' (syn.'Niu Leka') has been identified as especially attractive, with dense foliage and a thickened trunk base (bole) more typical of the talls. The slender base of most dwarfs makes them less stable in cyclones/hurricanes, unfortunately [4].

Malayan Yellow Dwarf variety growing in Malaysia. (Image "Cocos Nucifera - MYD Variety" by Jason Thien licensed under CC BY 2.0.

Other Advantages

Another major feature of the dwarf group is precocious bearing, coming into fruit within around 3 years (at only about 1 metre high) versus 6 or more years for the talls. The 30-40 years of productive life is only about half that of the talls, but quite long enough for most home gardeners [1, 5].

Coconuts produce male and female flowers on the same inflorescence, but the ability to produce both sexes at the same time affects efficiency of self-pollination. Fortunately, the dwarfs are usually self-fertile. However, if more than one type is growing in the area, including talls, the possibility for cross-pollination exists. This is worth remembering when when trying to source seeds of known heritage or using homegrown nuts for propagation.

On the other hand, controlled hybridisation programs are taking advantage of the dwarfs' genetics to improve coconut production. One of the highly-sought traits found in some dwarfs is resistance to the devastating Lethal Yellowing disease [4, 6].

Climate

The biggest limitation to cultivation of coconuts is climate. While they are associated with beaches due to their salt tolerance and seafaring seeds, they can be grown inland on a range or soils if the climate and rainfall/irrigation and humidity is adequate.

In the tropical north of Australia, coconuts will grow and fruit but have not yet been exploited commercially to any great degree. With many other tropical crops (e.g. vanilla, coffee, cacao) starting to be developed seriously in the north, this situation could change.

Fruiting coconuts in Florida occur as far north as Orlando, 28.4°N [7]. Coconuts have likewise been reported on the East coast of Australia as far south as Brisbane and the Gold Coast (approx 27-28° S) [8]. Years to fruit, reliability and quality of fruiting can be affected by unfavorable climate [2, 8], unfortunately, but this could be an acceptable risk for a home gardener developing an edible landscape. If the ornamental qualities of the tree alone are sought, the trees might be grown further south still before cold damage becomes a problem [9].

Coconut (variety unknown) on a Brisbane beach (27°20' S). (Image "House at Nudgee Beach, Queensland" by Kgbo is licensed under  CC BY-SA 3.0. Cropped from original)

Further experimentation with varieties could improve growers' chances of success in marginal areas. There appears to be little formal research on this to date. However, anecdotal evidence suggests the tall types are more cold hardy than the dwarfs [10] and that among the dwarfs the Malayan may be a little hardier than the Fiji [4].

A study on soil fertilisation [11] has demonstrated the potential of cultural practices to extend climatic range. Changes in climate could also alter the boundaries of growing in the future.

Coconuts, especially the dwarfs [12] require good consistent rainfall and would not be suitable for dry areas where supplemental irrigation could not be supplied but this is largely the case for any fruiting plant where a good yield is sought.

Flowers provide an alternative harvest

One of the problems encountered with growing them near their climatic limit is poorly formed nuts. If flowers are still made, however, perhaps it will still be possible to obtain an edible harvest by "tapping" them. That is, cutting off the inflorescence and harvesting the sweet sap that exudes from the stalk. This can be drunk fresh, used in cooking, fermented into alcohol or vinegar, or processed into syrup or crystalline sugar.

Dwarf varieties offer an obvious advantage for sap production given the tapping point must be regularly accessed during the period of harvest.

Coconut flowers are attractive to bees, so honey could also be considered an indirect edible harvest.

In Conclusion

Dwarf coconuts have a lot to offer gardeners living tropical regions. If you're gardening in the subtropics and you like to try your hand something a bit different, why not give one a go? It could be an interesting, and potentially rewarding, experiment.

References and Other Resources

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