Gardening Columns

Common foxglove is not only beautiful, it's also the original
source of the heart medicine digitalis.

Celebrate Plants!

First published on garden.org on April 13, 2006, by Suzanne DeJohn

April is National Garden Month, a perfect time to reflect on all the ways plants enhance our lives. Gardeners are familiar with the pleasures of gardening and the joys of an abundant flower and vegetable harvest. But let's take a step back and look at the bigger picture.

Simply put, all life on earth depends on plants. Or, more specifically, on photosynthesis, the method by which plants capture the energy of the sun and use that energy to manufacture carbohydrates. In doing this, plants make their own food and, in turn, make food for us. Also, during the process of photosynthesis plants consume carbon dioxide and release oxygen. So we rely on plants for both food to eat and air to breathe.

In addition to providing the means for our survival, plants also enhance our lives in countless ways. Look around you right now and consider what is derived from plants -- paper, wooden desk, cork bulletin board, cotton t-shirt, books. But this just scratches the surface. You might be surprised at just how pervasive plants and plant components are in the products you see and use every day -- and also how plants have transformed civilizations.

Food is perhaps our most obvious use of plants. If we're not eating the plants themselves, we're eating animals that ate plants. Wood is another obvious use. From toothpicks to lumber to paper to fuel, wood is everywhere. Then there are the plant-based fibers. Cotton, rayon, jute, flax, hemp, and ramie are all derived from plants. Human history is filled with references to our dependence upon plants. Imagine how different the world might be if Columbus didn't have fabric sails for his wooden boats!

Plants Have Changed the World
For thousands of years, plant-based essential oils, spices, dyes, and resins have been traded or used as currency. Wars have been fought over land on which certain valuable plants were found. The history of some regions is inextricably intertwined with their economies based on single plants, such as cotton or coffee. Even the frankincense and myrrh of Christmastime are derived from plants -- they're resins from different species of small trees or shrubs found on the Arabian peninsula.

Many inventions or discoveries began with plants. The development of the pneumatic tire was dependent upon the invention of vulcanized rubber, the base of which was latex collected from tropical trees. (Many plants produce latex -- if you've broken the stem of a ficus tree or poinsettia you've seen the white sap.) What a difference rubber tires have made when it comes to comfortable transportation!

Plant-Derived Medicines
Countless medicines are based on plant extracts. Quinine earned its place in history as a way to treat malaria, a devastating disease caused by a protozoan (a type of microorganism) transmitted by mosquitoes. Someone, somewhere, discovered that an extract from the bark of a specific type of tree, Cinchona, provided relief from the symptoms of malaria and aided in its cure. The substance was later identified as quinine. This discovery led to the settlement of regions previously uninhabitable due to the presence of malaria.

The medicinal use of opium can be traced back to at least 4000 B.C., and its derivatives are still used today. The source of opium is the opium poppy, Papaver somniferum. The immature seed capsules of this plant contain a resin that is dried to make raw opium. Morphine, codeine, and heroin are all derived from opium. Imagine what medical care was like before the pain-relieving properties of opiates were discovered!

Digitalis, originally extracted from the foxglove plant, Digitalis purpurea, is used in the treatment of congestive heart failure. The active substance in aspirin is salicin, or salicylic acid. The word salicin is derived from Salix, the genus name of willows from which the substance was first extracted.

Many of these substances are now made synthetically, but their names often reflect their "roots" in plants.

As you celebrate National Garden Month, ponder all the ways plants enhance our lives. Then dig in and plant a tree, start a new garden, or grow a few herbs on your windowsill!