Question 5

Does it flourish in a tough, disturbed,
abandoned site where little else can?

Weeds grow opportunistically and evolve to fill the spaces where soil needs protection.3 Nature gravitates towards balance or what scientists call homeostasis. The quickest plant to restore balance—or to win the ever-shifting battle for territory—survives the best. Enter one of Darwin’s finest: the unfussy, swift to sprout, omnipresent weeds.

If you see an unknown vigorous plant from your garden growing prodigiously well in an untended, abandoned, or disturbed area, suspect it. It may qualify as a weed. Here are some likely places to check:

•   Beside a highway where pollution from auto emissions and salt runoff from snow clearing equipment discourage all but the most intrepid.

•   By miles and miles of railroad tracks. By railroad and bus terminal parking lots.

•   Where the plows this winter yanked up your grass, left compacted tire marks and road salt.

•   Through the concrete on a highway, through asphalt on your driveway, through cement on a city street.

•   In an abandoned, rubble strewn lot.

•   By the fence that encloses the back parking lot at the local bank, supermarket, big-box super-store, or used car lot.

•   Where heavy construction equipment rolled over and compacted the soil or on new construction sites prior to landscaping.

•   By the edge of the woods where property lines end or by common walkways near the beach.

•   In un-buildable swamp land or wastelands.

•   Covering inactive farm fields.

Or perhaps the unknown plant stands out, bright and healthy, amidst a bed of cultivars recently decimated by drought, flood, disease, pests, malnutrition, herbicides, or heavy traffic.

Every time you read a book on weeds, under some heading such as “preferred locations” or “where does it grow”, you’ll note comments such as “found in recently disturbed places; wastelands; in neglected fields, rangeland, or pastures; by roadsides; or in compacted, infertile soil, etc.”

Local governments politic hard to get a majority of voters to agree to spend tax dollars to build a road for all to use. Not only does it takes time, effort, and compromise to reach the decision, but also it costs a bundle to cut an opening through the wilderness to build the road, the exits and other infrastructure.

Rarely can municipalities and their multiple committees also justify and agree upon the additional expenditure to select what to plant to adorn the broken soil. Then the question becomes what looks best where and in whose opinion. Lady Bird Johnson’s efforts to seed wildflowers by Texas highways, and other efforts like hers, rate as rare exceptions.

Large businesses with even larger parking lots spend their landscaping $$ on the front of the bank, store, or gas station. They may not have access to the areas, or may lack sufficient funds to warrant landscapes in the back wilderness outside the limit of their parking spaces.

Sometimes farms go fallow between plantings, between owners, or when they run out of resources.

Unanswerable questions may include: Who can make decisions for empty lots, deserted areas or at the edge of the Homeowner’s Association’s control? Then who will maintain and finance what the community decides upon?

Meanwhile the bare bosom of the soil is exposed to the elements. Nature abhors the vacuum. If no plants exist already, some will evolve to fill the welcoming void. The miracle is that even in the worst conditions, once the soil has some microbial life coupled with rainwater, with some air, and sunlight, plant life will volunteer.

Weeds resist disease and tough conditions, green up in even the most desolate of lots, in floodplains, and even bloom in the desert, once it rains. Some weeds resemble that tough, fortuitous, or gifted kid from a slum who survives to a productive adulthood, despite impossible odds. As I look at such a suspect, even one as invasive as Japanese knotweed, I find it hard not to admire its competitive hyper-vitality.

That doesn’t mean I let it take over in my garden. I don’t. I find my observations in these neglected areas a starting point to recognize what causes the plants in my garden to get pushed aside. I was born in NYC and spent most of my life in a city and I was naive about plants that might pose problems in my garden.  I needed all the help I could find to figure out what was and what was not a weed.

Here are a few weeds I came to recognize using this deductive method.

While taking the railroad back and forth to my weekend summer home, I saw swaths of a tall unidentified plant springing up by the tracks. When I took the bus to NY from the local bus stop, I saw it again. It looked like a leafy version of Liberace’s tall candelabras as it reached skyward from the compacted soil. Then I saw the TV ad for allergy medication and finally recognized its tiny bell-shaped top blooms. It was Common ragweed.

Left: Common ragweed candelabra of florets 4-6’ tall Right: Bell-shaped florets resemble cartoon ad for allergy meds

Common ragweed, Ambrosia artemisiifolia rates as a noxious weed, despite being a native of the U.S. It arrived as an accidental tourist in Europe, a kind of unintentional revenge for all the weeds that traveled to the U.S. from Europe.

A Common ragweed plant produces 3,000-50,000 seeds in “achenes”, or hard seedcases, topped with thorn-like outcroppings that can help the seeds hitch rides on passersby for as many as 400 miles. Frost-tolerant achenes can lay dormant, protected, for as many as 80 years until exposed to light by any soil disruption, a “buried seed strategy” that ensures its survival over time. Birds eat its abundantly produced achenes and break down the hard seedcases in their digestive tracts. This releases the seeds, encloses them in bird compost, and as birds “plant” or drop them, seeds become ready to germinate.

3 There is such a multiplicity of solutions to various niches in Nature, that when a niche opens up, and some hardy specimen emerges, it can flourish or invade. Any plant that appears may evaporate when conditions change and new competition arrives and so on.