Irish shamrocks evoke Saint Patrick's Day and the green landscapes of the Emerald Isle. But if you're seeking the real McCoy for your garden, you'd better start looking for some four-leaf clovers, because you'll need lots of luck. There is no authoritative version of the plant. Ironically, history makes it clear that there's also a big difference between shamrocks and four-leaf clovers.
"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 plants that look like clover. Consequently, several plants claim to be Irish shamrocks.
Even among the Irish, no consensus dubs one particular plant as the true Irish shamrocks, botanically speaking. A 1988 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 medic or medick (Medicago lupulina): 7%
- Wood sorel: (oxalis acetosella): 5%
- Red clover (Trifolium pratense): 4%
Various members of the Oxalis genus, with common names like black shamrocks (Oxalis triangularis), and wood sorrel (Oxalis montana) are sold as shamrocks for Saint Patrick's Day. These clover look-alikes are more easily cultivated as houseplants than real clover. Despite their use as shamrocks, the wood sorrels, etc. are not even related to clover (Trifolium).
Four-Leaf Clovers vs. Shamrocks
What medic, wood sorrels, and 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.
By definition, for a clover to represent the Trinity, it would have to bear only three leaves. So for all of the good luck they allegedly bring, four-leaf clovers technically can't be considered shamrocks at least not in the sense in which Saint Patrick made the latter famous.
Click Play to Learn the Difference Between Irish Shamrocks and Four-Leaf Clovers
It was ancient Celtic or Druid priests 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 lucky traditions surrounding shamrocks and four-leaf clovers, it is surprising that the clover is often looked upon as merely a common lawn weed to be killed. 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 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. But clover is beneficial to lawns with many of the desired characteristics of an ideal lawn, such as its tolerance of drought, lasting green color, soil aerating qualities, and softness.
Clovers Lawns vs. Grass
The reason clover lawns don't require the fertilization of a grass lawn is that these plants are nitrogen fixers like other cover crops in the pea family. Clover snatches nitrogen out of the air, bringing this essential fertilizer down to earth using nitrogen-fixing bacteria living in nodes along the roots.
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 that 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 clover 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 in the same lawn may provide the best answer. There is a growing movement in the U.S. to cut back on the amount of landscape consumed by lawn grass. The steam powering the movement against lawn grass comes from several driving forces:
- 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 lawnmowers.
- A desire for low-maintenance landscaping and cheaper alternatives to lawn grass. Mowing lawns, and applying herbicides, pesticides, and fertilizers to them costs money and hard work.
Having a clover lawn provides a solution to most of these problems. It is good for the environment and saves you money and labor. Experiment in a small area of your yard with a clover such as Miniclover (Trifolium repens) 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.