Horticulturalist Eli Biondi writes about the wonderful world of cacti - from the bright vibrant flowers to the succulent and juicy fruits and their uses.
What are Cacti?
Cacti are succulent plants in the Cactaceae family. They come from the Americas and have developed clever adaptations in order to survive arid climates and soil conditions.
Their stems are swollen to store water and are often covered in wax and hair to capture humidity and create shade. Their leaves are reduced to avoid transpiration and the roots are very near the surface of the soil to make the most of every available drop of water.
Cacti are famous for their peculiar shapes: columnar, spherical, cushion-like, and compact; but their most stunning features are their flowers which are showy in order to attract pollinators, which can be hummingbirds, bees, butterflies, moths and bats. Once the flower is pollinated, the yummy part develops: the FRUIT.
Photo of Harrisia fruit in Kew's Tropical Nursery
The infamous prickly pear
Opuntia ficus-indica is possibly the most popular edible Cactus. It is very sweet and fresh, with a sort of watermelon taste. Widely used in Mexico, the fruit can be eaten raw or used to make jelly, candies and drinks.
Photo of Opuntias flowering in the wild
In Mexican cuisine, another part of Opuntia is widely used: the green platyclades (pads). Chopped or sliced, they can be added to salads or omelettes, often combined with chilli. They are rich in vitamins and minerals and native cultures use them as a treatment for diabetes.
Opuntia are quite easy to grow at home. Some are fairly hardy in the UK, but it’s always better to protect them in winter. They like well-drained soil and plenty of water in the summer.
Another Cactus fruit used in the Southern United States and Mexico is Myrtillocactus geometrizans. This beautiful plant produces small edible berries that resemble Bilberry fruit (Vaccinium myrtillus) in shape, colour and taste, hence the scientific name.
In Arizona, Ferocactus wislizeni fruits are used to produce jelly and candy. Despite being a bit sour they are also used in salads.
Photo of Ferocactus wislizeni
The Dragon fruit or Pitahaya is the fruit of Hylocereus sp. and it is fairly easy to find in our supermarkets. Eaten raw, it has sweet juicy flesh with lots of seeds and a sort of kiwi texture. It can also be used to produce wine and juice.
The very showy flowers of Hylocereus open only at night as they are mainly bat pollinated. They can be eaten and used in tea.
Other Genera of Cacti produce fruits similar to the dragon fruit, such as Stenocereus sp. and Harrisia sp.
The iconic Saguaro
Carnegiea gigantea in the wild
Carnegiea gigantea (Saguaro) is native to the Sonora Desert, often reaching 15 m tall, and can live up to 200 years in healthy conditions. It is difficult to grow outside its range and is very slow growing.
The plant and its flowers, fruits and seeds are extremely important for wildlife. As a food source or a place to live, the Saguaro plays an important role in the ecosystem.
The fruits (called Papago) are not particularly interesting when eaten raw, but play a large part in the lives of Native Americans who, even now, harvest them to make nutritious syrup which can be consumed straight away or fermented to produce a type of wine used in ceremonies. The seeds are rich in proteins and fats and can be used to make flour.
- Eli -
Visit Kew's Cacti
Come and visit the Cacti in the Princess of Wales Conservatory. The Princess of Wales Conservatory recreates ten climatic zones. See Madagascan baobab trees, orchids from Central America and carnivorous plants from Asia.