21 July 2011

Weeds: In Defense of Nature’s Most Unloved Plants by Richard Mabey

Weeds of Oklahoma palmer amaranth

Weeds must be the most adaptive plants on the planet. No matter where you garden, weeds quickly move in.  Shade, baking sun, soaking soil, wind – none of those conditions can prevent weeds from planting their feet in soil that few other plants would tolerate.

Richard Mabey, England’s favorite garden writer, thinks we should love weeds and even respect them.  His new book, “Weeds: In Defense of Nature’s Most Unloved Plants” is a good read, even though it probably will not convince many gardeners to embrace weeds.
Weeds of Oklahoma Blue mustard

One of Mabey’s friends says that he never weeds his vegetable garden because weeds provide shade and moisture for the roots of his vegetable plants in the heat of summer. And, maybe we could all relax a little about our gardens’ uninvited plants.

In many neighborhoods there is a mixture of landscape and garden styles. Some have a lawn of native plants or weeds and others have carefully planted and tended grass. Gardeners remove weeds from flower, vegetable and herb beds. Lawn owners pull weeds from between the blades of grass.
Farmers plow and spray to keep the weeds out of fields. Many of us mulch everything in sight to prevent weed seeds from even sprouting.

Non-gardeners use their time in other ways. They do not tend fields, grass, beds, or pots. Not everyone is concerned with weeds.
Weeds of Oklahoma Cheat

“Plants become weeds when they obstruct our plans, or our tidy maps of the world”, says Mabey. “If you have no such plans or maps, they can appear as innocents, without stigma or blame.”
Most plants that are now considered weeds were valued plants at one time and in their home country.  For example Striga is now commonly called Witch weed because it is so destructive in field crops. But in its home country of Kenya, visiting dignitaries walked on paths covered with its pink flowers.

Weeds are widely travelled.  With the worldwide movement of people and products, it is impossible to tell where some of them started out. Gardeners on all five continents consider stinging nettle, chickweed, bindweeds and dock to be weeds but at one time they were only found in England.
Weeds of Oklahoma - Crabgrass

Plants travel the globe both intentionally and accidentally. The little wildflower known as American or Canadian fleabane, arrived in Europe inside a stuffed bird. Pirri-Pirri-Bur, a weed from New Zealand has entered most countries in wool shipments. Pineapple weed went from Oregon to international ports in the tread of tires the late 1800s.

Weeds are willing to grow where other plants will not. Mabey’s examples include bombed out cities, sites of chemical spills and cracks in concrete, rock and asphalt. In this sense, they are enthusiastically and beautifully growing in places that are bruised.
In order to thrive, weeds have to grow quickly or hold back and lie dormant. For example, Tumbleweed seeds can germinate in 36-minutes. Some Fat-hen (Lamb's Quarters) seeds sprouted after being found in a 1700 year old archaeological site and Rocket seeds in a 2,000 year old Roman site were still able to sprout and grow.
Weeds of Oklahoma - ryegrass

Weeds know other ways to survive. Field bindweed and creeping thistle put out chemicals that prevent grain crop seeds from germinating. American quackgrass not only takes the nutrients from the soil but has a chemical that kills corn.

On the other side of the fight, wheat, oats and peas, prevent Lamb’s Quarters from germinating and cotton prevents Witch Weed from sprouting.
Weeds in the Bible, plant names and more, the fascinating story of botany and history, “Weeds” by Richard Mabey, was published 2011, by Ecco Harper Collins (www.harpercollins.com). The 324-page hardback is $26 list and $12 at online retailers.

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