Clover, Shamrocks, and Oxalis: What's the Difference?

Learn About These Similar-Looking Plants

April 24, 2019
White Clover

Many of us remember being kids looking for the “four-leaf clover.” That brings us to today’s garden musings. What is the difference between clover, shamrocks, oxalis, and the mysterious four-leaf clover? Which plant is used in the lawn and garden, and which is a houseplant? Which is considered lucky? We’ll untangle the mysterious world of plant names…

What is Clover?

Clover is the common name for a ground cover plant often found in lawns and fields. It refers to a number of species in the Trifolium genus, with the word trifolium literally meaning “having three leaves.” White Clover (Trifolium repens) crowds out broadleaf weeds while growing harmoniously with grass. It will thrive in areas that are poorly drained or too shady for a conventional lawn.

Being a legume, the clover plant has the ability to convert nitrogen into fertilizer using bacteria in its root system, practically eliminating the need for additional fertilization.

Despite today’s push for perfectly green lawns (which involve a lot of chemicals), clover was not always viewed as a “weed.” The University of Minnesota Extension Service points out that, until relatively recently, it was standard practice to include clover seed in lawn seed mixes:

“Until the 1950s, clover was included in lawn seed mixes, as it was regarded as a prestigious lawn plant. It may be considered an attractive, low-maintenance ground cover that is soft to walk on, mows well and will fill in thin spots in a yard.”

Today, it seems clover is returning as a more eco-friendly lawn alternative. Since it is nitrogen fixating, it can supply its own nutrients to poor soil. Overseeding clover seed into your existing lawn is an easy way to establish a clover lawn. For lawns, the most popular is the white clover (Trifolium repens) because it is relatively low growing, tolerates close mowing, and outcompetes weeds.

See more about growing a clover lawn.

What is a Shamrock?

A shamrock is the symbol we associate with St. Patrick’s Day. Traditionally, “shamrock” refers to a three-leaf clover. A four-leaf clover is NOT the same thing as a shamrock. Someone’s confusing their lucky charms.

Why three leaves? According to legend, St. Patrick used the shamrock to explain the holy trinity with each leaf representing the Father, Son and Holy Spirit.

The word shamrock itself actually comes from the Irish word Seamrog meaning ‘little clover’ or ‘young clover’. According to Encyclopedia Britannica:

Shamrock [refers to] any of several similar-appearing trifoliate plants—i.e., plants each of whose leaves is divided into three leaflets. Plants called shamrock include the wood sorrel (Oxalis acetosella) of the family Oxalidaceae, or any of various plants of the pea family (Fabaceae), including white clover (Trifolium repens), suckling clover (T. dubium), and black medic (Medicago lupulina). Wood sorrel is shipped from Ireland to other countries in great quantity for St. Patrick’s Day.”

You’ll typically see the decorative Oxalis sold in stores, since it’s better suited as a houseplant (see more below).

False Shamrock (Oxalis regnellii​​)

What is Oxalis?

Oxalis, which are often sold as “shamrocks,” is a genus of plants that are native to most regions of the world, though they’re most numerous in the tropics. They may have green or purple leaves and white or pink flowers, and some cultivars, such as ‘Irish Mist’, have green leaves flecked with white. The whole plant is photophilic, meaning the leaves and flowers close up at night and open wide again in the morning.

Oxalis can be grown outdoors in the spring and summer in Zones 6 to 11, but they also make for great houseplants year-round. They like bright, indirect light and tend to bloom in fall, winter, or spring.

Since they are grown from bulbs, let them dry out a bit between waterings to prevent rot. Don’t fret if your indoor Oxalis loses all its leaves in summer. It isn’t dead. It just needs a dormant period, so let it dry out and put the pot in a dark place until it decides to resume growth in a few weeks. As soon as new leaves appear, bring it into the light and resume watering. These plants are low maintenance and long lived.

Here are a few of the more popular Oxalis species:

  • Sometimes called False Shamrock, Oxalis regnellii are native to South America. They have heart-shaped leaves instead of the clover’s oval-shaped leaves. (See photo, above.)

Purple Shamrock (Oxalis triangularis)

  • Purple Shamrock (Oxalis triangularis) is a subspecies of O. regnellii that hails from Brazil. It has large, handsome, purple leaves and pale lavender-pink flowers.
  • Lucky Leaf or Lucky Clover (Oxalis tetraphylla) is also known as four-leaved sorrel. Native to Mexico, it has four split green leaves with a dark maroon eye. The trumpet-shaped flowers of ‘Alba’ are white, ‘Iron Cross’ has pink flowers. 

Lucky Clover (Oxalis tetraphylla)

These plants all contain oxalic acid, the same chemical that makes rhubarb leaves toxic. If eaten in large quantities they can be poisonous to pets and small children. Don’t feed the leaves to your pet rabbit! 

What is a Four-Leaf Clover?

A four-leaf clover isn’t a variety; it’s just an unusual mutation of a three-leafed clover. It is meant to represent God’s Grace and is a “lucky” symbol because it’s hard to find.

Four-Leaf Clover

Traditionally, four leaves were considered lucky because they reflected the shape of a cross and thought to be magical or sacred. Eve supposedly took a four-leaf clover with her when she was banished from the Garden of Eden.

In the Middle Ages, it was believed that carrying a four-leaf clover would enable you to see fairies, recognize witches and evil spirits, and be protected from the evil eye. Even dreaming of clover was supposed to bring good luck.

Your chances of finding a four-leaf clover are 1 in 10,000! That’s where the luck comes in, I guess. If you do find one, giving it to someone else doubles your luck. 

Superstitions aside, clover is valuable plant in many ways. Bees and other pollinators can’t resist its flowers. Red clover is especially attractive to bumblebees. The plants can be turned into the soil as green manure. The roots host nitrogen-fixing bacteria that enrich the soil. The plants are high quality forage for many animals. This is the plant you want to feed to your pet bunny.

See more about growing a clover lawn.

About This Blog

Get inspired by Robin Sweetser’s backyard gardening tips and tricks. Robin has been a contributor to The Old Farmer’s Almanac and the All-Seasons Garden Guide for many years. She and her partner Tom have a small greenhouse business and also sell plants, cut flowers, and vegetables at their local Farmer’s Market.