Guarana is a climbing perennial vine indigenous to the Amazon basin, particularly northern Brazil on the Maués Açu River. The red-orange fruits of this species pop open to reveal shiny black seeds surrounded by a thin white pulp, giving the fruits an eyelike appearance. The common name, guarana, derives from a Tupi-Guarani reference to this resemblance.
Indigenous people used guarana as a stimulant and appetite suppressant as they traveled rainforest paths for days or weeks at a time. The plant contains three to five times the caffeine found in coffee beans — up to 5 percent by weight. The caffeine is thought to serve the plant as a kind of chemical defense, allowing it to repel pathogenic organisms that might otherwise attack the fruits and seeds.
Common Name: Guarana
Description: Climbing woody vine, up to 40 feet long; glossy compound leaves with toothed leaflets and pronounced veins; spikes of small white flowers are followed by bright red berries with shiny, dark seeds
Hardiness: To Zone 11
Flowering: Periodically throughout the year
Parts Used: Seeds
Range/Habitat: Native to the rainforests of the Amazon basin, especially northern Brazil
The pulverized seeds of guarana are made into a thick, brown syrup used in carbonated beverages that are widely consumed by the people of Brazil, as well as other guarana aficionados around the world. Marketed by Brazilian, Peruvian, and multinational corporations, the soda can often be found in supermarkets and small stores that cater to South American shoppers. It is also used as a caffeine source in energy drinks. (See “Field Notes” for more about preparing the beverage.)
The seeds’ high caffeine content speeds heart rate, relaxes blood vessels, and opens bronchial airways. Other potentially bioactive compounds in the seeds are tannins and saponins, which could be responsible for some of this herb’s effects. Guarana is taken to treat fatigue, headache, and diarrhea, as well as to increase libido. A recent small clinical trial with healthy adults showed that guarana can improve cognitive performance as well as mood.
The authors of this study noted that the result was most likely due not only to the caffeine in guarana, but also to other as yet undetermined substances. There are case reports of heart palpitations caused by taking large doses of guarana supplements, similar to the effects some people report after large doses of caffeine. Guarana also has diuretic activity. It is widely used in weight-loss formulas.
How to grow it
A tropical rainforest plant, guarana requires warm to hot conditions, high humidity, and acidic soil. Throughout most of North America, you’ll need a greenhouse to grow this tall vine.
Start with the freshest seed possible. Soak the seed in water for 24 hours, then plant it in pots filled with a moist growing medium. Set the pots in a bright location, atop a germination mat; maintain a minimum temperature of 65°F. Transplant 3-inch-tall seedlings to 8- to 10-inch pots (with drainage holes) filled with an acidic medium (a pH of 3.5 to 4.5). Provide good air circulation, and keep the soil moist but not saturated. Mist daily in the morning, but do not fertilize, so the soil will remain acidic.
Continue to pot up the growing plants, and provide support for the growing vines. Beginning in the second year, prune out old or damaged branches and unwanted new growth. Wait until the orange fruits split open to reveal black seeds. Remove the seeds, rinse them, then let them air-dry in a warm place. Toast the seeds in a moderately hot oven, then grind into a fine powder and store in an airtight container. To use, mix with warm water.