When the Beijing Olympic Games begin Friday, China will have planted more than 2-million trees in urban parks, including the new Olympic Forest Park. The primary goal isn't to create beautiful parks or provide shade for visitors. In this year of the "Green Olympics" initiative, Chinese officials hope the trees will reduce high levels of air pollution in the capital city. • But while the world focuses on Beijing this month, something much bigger is taking root in millions of acres of farmland in Southwest China that could reduce pollution on an Olympic scale. Jatropha (Jatropha curcas), known to environmental groups as the "bioenergy tree," is being planted in massive fields by farmers who have received subsidies and seedlings from the Chinese government. • Jatropha curcas is one of many species of jatropha, which are planted as a flowering landscape specimen throughout the Tampa Bay area. Jatropha is a hardy, Florida-friendly evergreen that produces pretty red flowers. But that's not this Cuban native's real claim to fame.
Nature's green gold
Oil from the jatropha tree is considered one of the top — if not the best — sources of biodiesel, the world's fastest-growing alternative to crude oil. China is poised to be the world leader in jatropha cultivation, with an estimated 2-billion gallons of jatropha oil in annual production by 2010.
Other countries are jumping on the jatropha bandwagon, including India, Africa, Brazil and the United States. In Florida, farmers are being urged by county and state officials to grow jatropha for biodiesel production and as an alternative to citrus, especially in groves hit by citrus canker and greening disease. Florida's "farm to fuel" initiative, backed by $25-million in state grants, could boost commercial investment in the biofuel industry in Florida, according to Mary Campbell, director of the Pinellas County Extension Service.
But oil isn't everything
In the home landscape, a single jatropha tree obviously wouldn't produce enough oil to generate power, plus you wouldn't choose Jatropha curcas for its beauty. But pick one of its ornamental relatives, such as Jatropha integerrima, and it will energize your garden with lovely color throughout the year, provide a bit of shade and, like all trees, it will help rid the air of pollutants.
There are many Jatropha species, most of them grown as ornamental evergreens that reach 10 to 20 feet high, ideal for a large container on the patio or in a small yard. A new plant will need pruning to keep it in a tree form, unless you prefer letting it branch out as a shrub. A relative of the poinsettia, its parts are poisonous and can irritate the skin.
At the garden center, you might find jatropha with several common names, including "Peregrina" and "Spicy Jatropha" (Jatropha integerrima). Plants labeled "compacta" will be smaller in size — usually less than 10 feet tall. Jatropha is often called "Physic Nut" or "Barbados Nut" here; the Chinese call it "Xiao Tong Z."
Beauties of jatropha
Jatropha produces clusters of five-pointed, star-shaped flowers that are a vibrant scarlet with a touch of yellow on the flower parts. The Chinese flag is the same scarlet, with five yellow stars in a cluster. Jatropha blooms throughout the year on new growth, so you can prune at any time of year.
Butterflies — particularly monarchs, swallowtails and zebras — are drawn to jatropha's flowers. So, too, are hummingbirds, who are known for their attraction to red.
If that doesn't sell you on this "bioenergy tree," perhaps jatropha's hardy disposition is reason enough. It does best in hot, dry, sunny conditions, although it will tolerate some shade (with decreased blooming). Other than its aversion to salt, jatropha's not picky, even when it comes to soil. There's no need to amend your soil before planting, but it can't hurt to regularly add organic matter and top it with mulch.
Considering that Jatropha curcas thrives in the wastelands of developing countries with little care, just imagine what its pretty cousin could do in your lovingly tended garden.
Yvonne Swanson is a freelance writer in St. Petersburg and a master gardener for Pinellas County.