Irish Shamrocks and 4-Leaf Clovers

History Draws Clear Distinction Between the Two

Red clover's leaf (image) is tripartite. This is why St. Patrick could compare it to the Trinity.
Image of red clover's leaf. David Beaulieu

The thought of Irish shamrocks evokes visions of the green landscape of the Emerald Isle as surely as does St. Patrick's Day itself. But there is no real McCoy that can claim to be the authoritative version. If you have your heart set on making such an identification, you had better start looking for some 4-leaf clovers, because you'll need lots of luck! But ironically, the latter, themselves do not qualify, for reasons that history makes clear.

The term "shamrock" derives from the Irish word, seamrog, which translates as "little clover." Rather vague, considering that there are many kinds of clovers -- and even more plants that can pass as clovers to the layman. Consequently, in St. Patrick's Day celebrations a number of plants serve as Irish shamrocks. But identifying a particular plant as the one and only true Irish shamrock is a dubious practice, botanically speaking.

Even among the denizens of Ireland, itself, there is no consensus that dubs one particular group of plants as the true Irish shamrocks, 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 four plants. Three of the plants are clovers, while the fourth is a clover-like plant known as "medick." All four are in the Pea family:

  1. Lesser trefoil, or hop clover (Trifolium dubium): 46%.
  1. White clover (Trifolium repens): 35%.
  2. Black medick (Medicago lupulina): 7%.
  3. Red clover (Trifolium pratense): 4%.

Various members of the Oxalis genus, such as the so-called "black shamrocks" and the wood sorrel family (e.g., Oxalis acetosella) are also sold as shamrocks for St. Patrick's Day. These clover look-alikes are more easily cultivated as houseplants than is real clover, making them popular for interior decorating during St.

Patrick's Day celebrations. But the wood sorrels, etc. are not even related to the four plants listed above. One would be quite justified at this point in asking, "What's the story here, how can such a diverse group of plants all be considered Irish shamrocks?" And there is, indeed, a story that accounts for the confusion ....

The Legend of St. Patrick and Irish Shamrocks

What medick, the wood sorrels and the true clovers all have in common is a trifoliate leaf structure, i.e., a compound leaf with three leaflets. The number 3, of course, 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 3 (and only 3) leaves. So for all the good luck they allegedly bring, 4-leaf clovers technically can't be considered shamrocks (not in the sense that St. Patrick made the latter famous, at least).

But the foregoing does explain the ease with which multiple "shamrock" representatives are accepted. A candidate's trifoliate leaf structure can override its family history, including geographical anomalies. For instance, some of the wood sorrels widely used in the U.S. as Irish shamrocks are of South American or Central American heritage, which hardly conjures up images of the grassy slopes of the Irish countryside!

Next we will look at the belief in 4-leaf clovers as lucky charms.

As we have seen above, the three leaves of the "shamrock" represent the three persons of the Trinity. But what of the notion that four leaf clovers bring good luck? Since the operative number here is four, the history behind these lucky charms clearly must be different from the Trinitarian tradition behind the shamrock. It is widely believed that the significance invested in them goes back to pre-Christian Celtic times, although I haven't found the evidence to back up this assertion.

The Williams College website does allude to a legend involving Adam and Eve, stating, "Eve is said to have carried a 4-leaf clover with her as she left the garden."

Celtic dominance once extended across Ireland and much of Western Europe. It was the Druids (Celtic priests) who elevated four leaf clovers to the status of good-luck charms, allegedly potent against malevolent spirits. Their status as Celtic charms is the origin of the modern belief in their power to bestow good luck.

What do four leaf clovers mean, symbolically? Besides good luck, they are sometimes said to stand for faith, hope and love. But another interpretation is widely known via the following verse:

I'm looking over a four-leaf clover
That I overlooked before.
One leaf is sunshine, the second is rain,
Third is the roses that grow in the lane.
No need explaining the one remaining
Is somebody I adore.
I'm looking over a four-leaf clover
That I overlooked before.

The first literary reference to draw on the tradition of four leaf clovers as good-luck charms seems to have been made in 1620. In that year, according to the University of Illinois, Sir John Melton wrote, "If a man walking in the fields find any four-leaved grass, he shall in a small while after find some good thing." It is estimated that, on average, there are 10,000 three leaf clovers for every instance of a true four leaf clover.

Oxalis Deppei as a "Four Leaf Clover" Substitute?

Nowadays one can take the easy route to finding "four leaf clovers." Oxalis deppei is widely sold as the "good-luck plant," because it bears a leaf that always has four leaflets. However, as already noted, plants from the Oxalis genus are not true clovers, only clover look-alikes. Besides, when that fourth leaflet is automatic, how could it possibly hold its own with a true good-luck charm? Oxalis deppei strikes me as being suitable for gags only; there's not an ounce of romance in this phenomenon....

Considering the St. Patrick's Day traditions surrounding shamrocks and four leaf clovers, it is surprising that the clover is often looked upon as a weed, the killing of which we deem central to the care of our lawns. But it was not always so. Indeed, 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."

Landscaping enthusiasts believe in making their own luck through solid decision-making, rather than relying on Celtic charms and the proverbial "luck of the Irish." The information below may not send you scurrying to find any four leaf clovers. But it may make you re-think your attitude toward your lawn....

Do you automatically expect to find a lawn of green grass -- and green grass alone -- in front of a suburban or rural home? For those of you who have grown up under the hegemony of grass (as discussed in my brief history of lawns), the grass lawn is practically an institution. The corollary to that attitude is that anything else growing in said space is harmful -- a "weed."

But might not clover be beneficial to lawns?

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. Are you sure the grass is greener?

Close your eyes and dream for a moment. Imagine yourself opening your front door and stepping out onto your ideal landscape. What would some of the components of such a landscape be? Well, there would probably be some bright colors to catch your eye -- bedding plants serve this purpose. To punctuate the flat expanse of green between your home and the street, you'd probably want to add some trees (or bushes) to establish a vertical dimension. Perhaps a hardscape element such as a garden arbor or a water feature will function as a focal point.

But now we come to the component alluded to above, namely, the "carpeting" for your outdoor living space. For you will need to fill in between your bedding areas and trees and focal point with something that you can walk on.

While mulches and hardscape paths adequately fill this role for some people's tastes, other folks like the feel of something live under their feet. Close your eyes again and picture the ideal living carpet of green. What qualities would it have?

Ideal Qualities of a "Carpet" for Outdoor Living:

  1. It stays a luscious green all summer, without being irrigated profusely (i.e., it's drought-tolerant).
  1. It out-competes weeds fairly well, obviating the need to apply herbicides. Your carpet competes so well for growing space that the competition is choked out.
  2. It doesn't need to be fertilized.
  3. It is also relatively free of damage from insect pests, so that you do nott have to bother spraying pesticides on it.
  4. It aerates the soil on its own, so that you don't have to worry about counteracting soil compaction.
  5. It is soft to walk on.
  6. It attracts beneficial insects, including honeybees.
  7. It rarely has to be mowed.
  8. It doesn't suffer the discoloration from dog urine known as "dog spots."
  9. And if, despite all these benefits, you should ever want to replace it with a different kind of green carpet, it helps you to do so by improving the soil on its watch. Its ability to aerate the soil and pump nitrogen into it means that succeeding generations of plants using that soil will be better off.

"All right," you may object, "it's time to stop dreaming and get back to reality. No grass has all these qualities." Correct. But I didn't say that it was a grass. In fact, the "ideal" qualities that I just listed (with the possible exception of #1) describe not a grass, but clover. And in this case, the ideal meets the real -- clover possesses all 10 of the qualities listed above!

The question now becomes, "Why would you possibly choose grass over clover?" The 4-leaf clovers discussed on earlier may or may not bring you good luck, but there's no question that having clover in the lawn brings some distinct advantages.

Should clover replace grass as the "living carpet" of choice (even if only partially, in the form of a beneficial mix of grass and clover)? Does growing clover instead of lawn grasses have any disadvantages? Next we will explore these matters and more.

Further exposition is in order regarding some of clover's "ideal" qualities, as discussed on earlier. To begin, the reason clover lawns wouldn't require fertilizing, as does grass, is that these plants are nitrogen fixers. They share this ability with other cover crops in the Pea family.

Clover snatches nitrogen out of the air, bringing this most 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 of maintenance.

If you're interested in cheap, low-maintenance alternatives, this sounds like magic, doesn't it? At the very least, I'd say any homeowner would be lucky to have such a plant, instead of turfgrass.

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 listed on earlier: its ability to attract honeybees, and the fact that clover lawns wouldn't need to be mowed nearly 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 turfgrass. This flower draws bees and other beneficial insects to your landscape. But if you are allergic to bee stings, to be on the safe side you can simply mow more frequently during the blooming season.

If you are not allergic to honeybees, this should not be a concern; for honeybees tend not to be aggressive away from the hive anyways.

The Movement Against Lawn Grass

Of course, it's not a matter of "all or nothing," and one advantage turfgrass 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. One popular website devoted entirely to the movement against lawn grass is The steam that powers the movement against lawn grass derives from a number of sources, including:

  1. An urgent sense in North America that drought is increasingly becoming a factor when making choices about what to plant, as discussed in my xeriscaping article. Simply put, homeowners are tired of seeing their lawns die every summer -- or of paying through the nose to prolong a lawn's life. Hopefully, more drought-resistant strains of clover will be developed to address this issue.
  2. Concerns about the pollution caused by herbicides, pesticides, chemical fertilizers and the emissions from lawn mowers.
  3. 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.

Again, having a clover lawn provides a solution to most of these problems -- environment, money and labor.

I have been experimenting with a white clover called Miniclover® in my own yard. The arguments in favor of trying an experimental clover lawn in a small area seem overwhelmingly convincing to this observer. You may still only rarely come upon a 4-leaf clover, even if you grow clover in front of your home as an alternative to lawn grass. But you'll feel so lucky to have clover as your "outdoor carpeting" that it will seem like you have a whole lawn-full of these legendary good luck charms.

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