Flower of the Week: Zonal Geranium

Zonal geranium’s flowers grow densely at the top of the plant and cluster into a small flower ball. The flowers are white, orange, pink, or red, some muted, some bright, and come in a variety of shapes, so it’s easy to find one you will like. Its leaves are round with serrate or ruffled margins, and patterned as well, so it’s attractive even when it’s not in bloom. Some species of the genus are fragrant, and they can become an indispensable element in the kitchen.

Zonal geraniums are native to southern Africa and spread to Europe through trade voyages in the 17th century. They are now one of the most common potted flowers around the world. A new trendy variety is cultivated almost every year to take the market by storm. Bring it home to fully appreciate this beauty from thousands of miles away, and let this little darling bloom on your windowsill.

Distinguishing Zonal Geraniums from the Fragrance

Zonal geraniums appear in many literary works of the 19th century. Although both zonal geranium and cranesbills are colloquially known as geraniums, we can distinguish them via the textual description of their fragrances. For example, George Eliot, in Scenes from Clerical Life, used the fragrant geranium in gin as a metaphor for the arrival of the sweetness of spring.

In real life, these aromatic zonal geraniums can be used in baking or bartending to add layered depth to foods and beverages. However, not all zonal geraniums are fragrant, so if you happen to have grown unscented zonal geraniums, don’t question whether you’ve bought a fake one.

A Mosquito-Repellent Scam Involving Zonal Geraniums

At the end of the last century, a zonal geranium variety called “citrosa geranium” claimed to have been genetically engineered to repel mosquitoes by its aroma. It became wildly popular in the U.S. and Canada, with one plant selling for up to $14. But later, researchers found that the plant’s aroma didn’t work as a mosquito repellent, and mosquitoes rested directly and harmlessly on this geranium.

Pelargonium graveolens is also called mosquitoe-repellent grass

Many websites still sell this geranium, but its description has changed from “able to repel mosquitoes” to “proven unable to repel mosquitoes.”

We Learned about Color Blindness from It

British chemist John Dalton is known for founding atomic theory and seen as the father of modern chemistry, but his work on color blindness was also pioneering. Being color blind himself, Dalton realized that what others saw as pink zonal geraniums were closer to sky blue in his eyes.

Dalton documented the differences between his and other people’s vision, and eventually presented the first systematic study of color blindness at the Manchester Literary and Philosophical Society in 1794. Dalton’s deuteranopia, or color blindness, is therefore known as daltonism.

The rainbow colors in the eyes of people with daltonism.

Can I Grow Zonal Geranium Well?

Zonal geraniums prefer a warm environment, with winter temperatures around 5-10°C. If you are in a colder area, consider growing it indoors. Geraniums like ample sunlight and can tolerate shade, so you can grow it indoors on a windowsill.

Zonal geranium grows best in fertile, well-drained soil. It can tolerate moderate drought, so wait until the soil surface is dry before watering it. Less frequent watering is required in winter. It can be fertilized every two weeks in spring and summer, and an application of potash fertilizer before flowering will encourage blooms. After flowering, deadhead spent flowers to reduce nutrient consumption.

Size: 30-60 cm (1-2 ft) tall

Hardiness: USDA Hardiness Zones 9-12

Light: Full sun to half sun

Soil: Fertile, well-drained

Bloom time: Summer or fall