The thought of Irish shamrocks evokes visions of the green landscape of the Emerald Isle as surely as does Saint Patrick's Day, itself. But if you're seeking the real McCoy, you'd better start looking for some four-leaf clovers, because you'll need lots of luck: There is no authoritative version. Ironically, there's also a big difference between shamrocks and four-leaf clovers, for reasons that history makes clear.
"Shamrock" a Nebulous Term
The term shamrock comes from the Irish word seamróg or seamair óg, which translates as "little clover." That's rather vague, considering that there are many kinds of clovers (and even more plants that often pass as clovers). Consequently, in Saint Patrick's Day celebrations a number of plants serve as Irish shamrocks.
Even among the Irish, there is no consensus that dubs one particular group of plants as the true Irish shamrocks, botanically speaking, as was reported in a 1988 survey. The survey, conducted at the National Botanic Gardens, Glasnevin, Dublin, revealed that when the Irish wear the "shamrock," it can be any one of five plants. Three of the plants are clovers while the fourth is a clover-like plant known as "medick" and the fifth is a wildflower that resembles a clover called "wood sorrel":
- Lesser trefoil, or hop clover (Trifolium dubium): 46%
- White clover (Trifolium repens): 35%
- Black medick (Medicago lupulina): 7%
- Wood sorel: (oxalis acetosella): 5%
- Red clover (Trifolium pratense): 4%
Various members of the Oxalis genus, such as the so-called "black shamrocks" (Oxalis regnellii) and the wood sorrels (for example, Oxalis acetosella) are sold as shamrocks for Saint Patrick's Day. These clover look-alikes are more easily cultivated as houseplants than real clover, making them popular as indoor decorations for Saint Patrick's Day. Despite their use as shamrocks, the wood sorrels, etc. are not even related to Trifolium.
Four-Leaf Clovers vs. Shamrocks
What medick, the wood sorrels, and the true clovers all have in common is a leaf made up of three leaflets. The number three is significant in the Christian religion because of the doctrine of the Trinity. Irish legend has it that the missionary, Saint Patrick, demonstrated the principle behind the Trinity using a shamrock, pointing to its three leaflets united by a common stalk. But there is no way of determining with certainty the exact plant referred to in the legend.
This much we can say about Irish shamrocks, however: By definition, for a clover to represent the Trinity, it would have to bear three (and only three) leaves. So for all of the good luck they allegedly bring, four-leaf clovers technically can't be considered shamrocks (not in the sense in which Saint Patrick made the latter famous, at least).
It was the priests of the ancient Celts, called "Druids," who elevated four-leaf clovers to the status of good luck charms, potent against evil spirits. This is the origin of the modern belief in their power to bring good luck.
For the most part, the four-leaf clover is not a separate species, just a freak of nature. That's why people feel so lucky when they stumble across one. If you want to "make your own luck" and don't mind going outside the Trifolium genus, buy an Oxalis deppei plant. Oxalis deppei is widely sold as the "good-luck plant," because it bears a leaf that always has four leaflets.
Clover Beneficial to Lawns
Considering the Saint Patrick's Day traditions surrounding shamrocks and four-leaf clovers, it is surprising that the clover is often looked upon as merely a common lawn weed, the killing of which we deem central to lawn care. But it was not always so. Indeed, the book Beautiful No-Mow Yards: 50 Amazing Lawn Alternatives points out that, until recently it was standard practice to include clover seed in lawn seed mixes.
"It was a common component of lawn seed mixes back before broadleaf herbicides became a widely used lawn care strategy. Clover was valued as a built-in fertilizer for the grasses, through its ability to fix atmospheric nitrogen, and also for extending the lawn's season of green."
The grass lawn is practically an institution for those who expect to find a space composed solely of green grass in front of a suburban home. In their opinion, anything else growing in the space is harmful (a "weed").
But clover is beneficial to lawns. Moreover, it goes largely unquestioned that grass will serve as your "carpeting" for outdoor living. But perhaps it is time to ask some basic questions about lawn care and the landscaping needs in front of a house.
Clover actually has many of the desired characteristics of an ideal lawn, such as its tolerance of drought, lasting green color, soil aerating qualities, softness, and more.
Clovers Lawns vs. Grass
Clover snatches nitrogen out of the air, bringing this essential fertilizer down to earth by means of nitrogen-fixing bacteria living in nodes along the roots (all at no cost to you, in terms either of money or maintenance).
You may also be wondering about clover's ability to aerate the soil, thus reducing concerns over soil compaction. Clover tolerates compacted soil better than lawn grass does. It has longer roots, enabling it to access water at deeper levels.
Finally, a word about two of clover's other ideal qualities: its ability to attract honeybees, and the fact that clover lawns usually don't need to be mowed as often as do lawns composed of grass:
- Clover puts out a mildly attractive flower, which could easily be listed as another advantage it has over grass. This flower draws bees and other pollinators to your landscape.
- Honeybees tend not to be aggressive away from the nest, but if it's a concern you can simply mow more frequently during the blooming season.
The Movement Against Lawn Grass
But it's not a matter of all or nothing, and one advantage grass does have over a clover lawn is that it stands up better to heavy foot-traffic. Mixing clover and grass together in the same lawn may provide the best answer for most people. But there is a growing movement in the U.S. to cut back on the amount of landscape consumed by lawn grass. The steam that powers the movement against lawn grass comes from a number of sources, including:
- Concerns over the excessive use of irrigation, which is why more people are turning to xeriscaping. Homeowners are tired of seeing their lawns die every summer or of paying through the nose to prolong a lawn's life.
- Concerns about the pollution caused by herbicides, pesticides, chemical fertilizers, and the emissions from lawn mowers.
- A desire for low-maintenance landscaping, as well as cheap alternatives to lawn grass. Mowing lawns, and applying herbicides, pesticides, and fertilizers to them, means more than just pollution. All of this costs money and causes you work, as does the need to aerate and irrigate lawn grass.
Having a clover lawn provides a solution to most of these problems. It is good for the environment, and it saves you money and labor. Experiment in a small area of your yard with a clover such as Miniclover (a type of white clover) to see if a clover lawn is right for you.
Medland, Vicki. "Wisconsin Shamrocks! – Biodiversity". University Of Wisconsin Green Bay, 2015, https://blog.uwgb.edu/biodiversity/2015/03/shamrocks/.
Nelson, Ernest Charles. Shamrock: Botany and History of an Irish Myth. Boethius Press, 1991.
Hadden, Evelyn. Beautiful No-Mow Yards: 50 Amazing Lawn Alternatives. Timber Press, 2012.
Miller, G. Lawns. North Carolina Extension Gardener Handbook, edited by K.A. Moore and L.K. Bradley, NC State Extension, 2018.
Agriculture and Air Quality. United States Environmental Protection Agency.