Essentially, weeds are problem plants growing where they are not wanted’. They are usually species introduced to a region where the pests and diseases that would naturally keep them under control are absent. As well, they are successful, opportunistic plants, highly effective at reproducing, often setting prolific amounts of seed which can remain viable for years – ‘one years weeds = seven years seeds’.
Some came by accident, carried unknowingly by humans, animals and/or cargo but a great many were introduced on purpose. Why would any sensible person do such a thing? Many of these plants were our forbearer’s medicines and potherbs. Their stories are intertwined with ours and make fascinating studies.
For example clovers are natives of Britain now found worldwide. Until late Tudor times they were called clavers and gave their name to various places in England, Claverdon, Claverton and Clavering. The Anglo-Saxons called them cloeferwort perhaps referring to the three leaflets resembling the three-knotted club of Hercules – in Latin a clava. These were considered lucky, even more so when there were four leaves and were used as charms against witchcraft. White clover is also called Dutch clover, as the Dutch were the first to realize its benefits as an agricultural crop, its legumous ability to enrich the soil with nitrogen. As medicine they were valued for their sodium content, which reduces acidity and aided the assimilation of iron in the body. A tea has had many uses over the centuries, as an aid to the kidneys, to relieving coughs and more embarrassingly to remedy excessive flatulence. These days’ organic gardeners recognize clover as a good green manure crop and a way to keep a green ‘lawn’ in drought times.
As this shows often a weed is ‘a weed in the eye of the beholder’. Dry land gardeners know that some common garden weeds, including lamb’s-quarters, pigweed and nettle are drought-tolerant, edible and as nutritious as spinach. Nature lovers gardening for wildlife know that encouraging good weeds with wildlife values in a corner of the garden will provide both food and cover. Examples include milkweed for monarch butterflies, mullein holding seeds and shelter for beneficial insects above the snow, nettles are a favorite of butterflies and bumblebees while chickweeds provide a preferred food to songbirds.
Interesting as this is what most of us really want to know is how to control weeds. This will depend on where they are and whether they are annuals or perennials. Annual weeds come from seed anew every spring so a sharp hoe is your best ally. Every one or two weeks slicing just below soil level will control seedlings as well as larger annuals. It is best to hoe when the weather is dry and warm so the weeds will die and any seeds unearthed don’t get the chance to germinate. Perennial weeds will need to be dug up and all roots physically removed. Any little piece of root left will develop into a new plant so great diligence must be practiced or the weeds will once again infest your garden. Around delicate plants one will need to hand weed both annual and perennial weeds.
If this sounds daunting it is worthwhile to reflect that nowhere is the old saying an ounce of prevention is worth a pound of cure more appropriate. When preparing a new bed, dig out the large weeds, cover the area with clear plastic and fasten it in place for two months in the heat of summer. This will ‘sterilize’ your soil and leave it ready for amendment and planting in the fall. Here is the perfect time to employ mulching whether using well-rotted compost, bark chips or a living mulch such as vinca, pachysandra or pulmonaria. The trick is to make sure your mulch is deep enough to discourage weeds and to make removal of those determined to invade your garden, easy to pull out. If your established beds are so thick with weeds that hoeing, digging and hand weeding are ineffectual it may be necessary to remove favorite plants and prepare the bed from scratch as a new bed.
However we deal with weeds reflecting on their history and their determination to survive in the most hostile of situations may at least make the chore a little more interesting!