Clover: It’s Not a Weed Anymore
For my neighbors, to whom I apologize for what looks like a lawn being overtaken by weeds.
I am deliberately allowing clover to grow freely in my lawn. Here’s why.
- Clover saves water (deep roots).
- Clover won’t take over the lawn (grows where other plants won’t).
- Clover provides natural fertilizer for the grass (especially nitrogen).
- Clover supports the bee population (due to their blossoms) and other beneficial insects (ladybugs, other insects that prey on grubs that damage the lawn).
- Clover was the victim of a marketing conspiracy.
Pragmatic Reasons to Convert Your Lawn
First, we live in a drought-prone area and risk being fined for excessive water usage. A 2017 EPA report suggests that 30% of the average American household’s water use is for lawns. Of that 30%, half is wasted due to evaporation, wind or runoff. The typical modern lawn (exclusively turfgrass) cannot be sustained by rainfall alone — certainly not where we live!
Second, turfgrass needs fertilizer. Fertilizer is generally categorized by its N-P-K ratio (nitrogen, phosphorus, and potassium) and the vast majority is synthesized (organic fertilizer is typically bird or bat guano). Of the three, nitrogen is the most important nutrient. Nitrogen is also a readily abundant element, but it’s a gas — we’ll come back to that in a minute. Phosphorus and potassium cannot be synthesized; they must be mined. Potassium is found primarily in Canada and the former Soviet states. 85% of phosphorus lies in Morocco’s Polisario Front which is a geopolitical hotbed at the moment. At some point, we won’t be able to obtain these nutrients.
Farmers are reasonably efficient at applying fertilizer but suburbanites are not — some estimates suggest that lawns get ten times the fertilizer they need. And they get overwatered (see the first item), so the fertilizer runs off into the storm drains. Synthetic fertilizer runoff pollutes the water table, rivers and eventually the ocean causing dead zones (areas of low oxygen that can kill fish and marine life) like the nearly 7,000 square mile area in the Gulf of Mexico. Suburban drinking water is tested for nitrate contamination, unlike well water in agricultural regions.
Third, along with fertilizer, lawns need herbicides (i.e., weed killer) — the most popular, generically 2,4-D — which might be carcinogenic. The World Health Organization says it probably is; the U.S. Environmental Protection Agency says it probably isn’t. If it is, there’s a risk of abnormally shaped sperm and thus fertility problems in addition to cancer. By the way, glyphosate (RoundUp) is much worse.
A Quick History Lesson
Blame the Scots
The idea of a lawn in front of your home originally came from Scotland where such grasses grew natively but required laborers to maintain it, thus a sign of nobility. The practice came over to North America during the Colonial days. After the Revolutionary War, anything ‘British’ fell out of favor, but lawns survived in Canada thanks to Scottish immigrants and their love of golf. Eventually, lawns migrated to the United States by around 1900. Lawns remained an aristocratic thing until World War II. One factor causing change after this time was the motorized lawnmower, so a staff of laborers was no longer a necessity; the homeowner could mow their own lawn. Levittown, PA, the first massive-scale suburb, included a finished lawn for every home. Returning veterans with their crew cuts were predisposed to keep a crew cut lawn or so the story goes.
Blame the Nazis
Let’s back up a little bit. Between World War I and World War II, there was consolidation in German companies because of the financial stress of reparations. IG Farben became one of the largest companies in Europe. Fritz Haber (subsequently “the father of chemical warfare”), received a Nobel Prize for developing the process of synthesizing ammonia (nitrogen, a key component of explosives for bombs) from air. Carl Bosch, in the BASF division of IG Farben, began commercializing ammonium nitrate as fertilizer for a desperately hungry continent. At the end of World War I, the secret details were negotiated away to the French, British, and Americans. We’ll get back to this in a minute.
In the time between the wars, Fritz Haber was a global hero. In “Enriching the Earth”, Vaclav Smil implies that two of every five people on Earth today would not be alive without Haber’s invention.
Then came the Third Reich and the chemical companies were diverted to more nefarious projects (Zyklon B, initially a pesticide, was used in the gas chambers). Some Jewish chemists escaped and began working in America. Working in secrecy from each other during World War II, separate groups in the UK and US developed 2,4-D. The plan was to starve the Germans and Japanese into submission by using it to kill their potato and rice crops. Unfortunately, those crops were resistant and only the weeds died. After the war, it was introduced commercially as a weed killer.
How does the Haber-Bosch process work? The short version is that natural gas is combined with steam and burned, then the CO2 is extracted somehow leaving ammonia. Today, 33 million BTUs of natural gas are required to make one ton of ammonia. In 2013 when natural gas was $2.50 per thousand cubic feet, $82 worth of gas generated one ton — which sold for $800. Fracking makes natural gas even cheaper.
Blame the Marketing Guy
At the end of World War II, the most prominent species in lawn seed mix was — wait for it — clover. Up until that time, the ‘ideal’ lawn contained a good amount of clover. Like other legumes, clover takes nitrogen from the air and fixes it (chemically combines it with other elements as a solid molecule, not a gas) in the soil providing natural fertilizer for the rest of the lawn. Better gardeners knew that grass near clover was greener than grass further away. So more clover in your seed mix meant a greener lawn.
Unfortunately, 2,4-D killed broadleaf species indiscriminately. It killed clover. I assume that people noticed and complained. The herbicide companies tried to find a solution, but couldn’t. Seed mix stopped advertising clover. Herbicide advertisements started referring to clover as a “weed” that should be eliminated from your lawn …we bought it. (This is why you think clover is a weed and much is written about how to eradicate it.) But then the lawn wasn’t as green and needed a big dose of nitrogen to make it grow.
There is a book that you can still buy, “YOUR LAWN: HOW TO MAKE IT AND KEEP IT” by Dr. Milton Carleton (1971). He was one of the scientists who introduced 2,4-D in the 1940s.
“The thought of white Dutch clover as a lawn weed will come as a distinct shock to old-time gardeners,” Carleton wrote. “I can remember the day when lawn mixtures were judged for quality by the percentage of clover seed they contained. The higher this figure, the better the mixture… I can remember the loving care which old-time gardeners gave their clover lawns. The smug look on the face of the proud homeowner whose clover stand was the best in the neighborhood was really something to behold.”
He knew. And I appreciate opportunities to be smug.
Recapping, in Reverse-Order
- Burning fossil fuels, health risks, disingenuous marketing — bad.
- Bombs, chemical warfare, synthetic fertilizer, weed killer — bad.
- Scots, deep roots — good.
- Saving water — good.
- Clover lawns — good.