Return to home page WEEDS HOW TO CONTROL AND LOVE THEM A weed is most commonly described as a plant growing in the wrong place. This could include rogue potatoes that spring up in the wrong parts of the garden, strawberry runners that creep amongst your vegetables and even vegetables that have found their way, uninvited, into the flower-beds. But, when we refer to weeds, we really think of plants like couch, chickweed, knotweed, and the dreaded dandelion. So what makes these plants weeds? Firstly, they compete with your vegetables, flowers and lawns for

light, water and food. They may also contain poisons and harbour pests and diseases. The main problem, however, is their tenacity. They are determined to stay, or return at the first opportunity. They take full advantage of your activities in the garden, quickly spreading over bare ground when you cultivate the soil.

In nature, these 'weeds' are highly successful wild plants, adapted to rapidly colonise bare ground or land that is constantly being disturbed. They are 'programmed' for survival. Some weeds can regenerate themselves from tiny pieces of root or stem. Others can produce thousands of seeds which germinate, grow, and set seed again in a few weeks.

Weeds also have many beneficial properties. Some improve the soil, some attract wildlife and predators, some can be eaten and many were used in the past for their herbal properties. Also, it is often forgotten that many of them are beautiful wild flowers in their own right. So, before you pull out the next weed, think again.
The first section describes and illustrates many of the common and some of the not so common garden weeds, and looks at their properties and the way that they grow. In certain situations you have to remove weeds.

THE ECOLOGY OF WEEDS

If you can get to understand your weeds and how they work, then you may come to tolerate some. This understanding will also help you to control weeds effectively and organically. Weeds are successful because:

1. They can spread rapidly, by seed and or vegetatively.
   

2. They are aggressive, fast growing and real survivors.
   

3. They are variable and can adapt rapidly to hostile conditions.
   

4. They grow where they will find nourishment and where their living conditions are fulfilled.
   

5. They live in communities and not as a monoculture.
   

6. They are, in general, more resistant to disease than crops.
   

7. They can sometimes travel great distances to a more suitable site.
   

8. Offspring may be able to live in an area that the parents could not tolerate, as they are genetically different.
   

9. Seeds can provide a fresh start if the parent has fallen foul to a disease.

POLLINATION

Many weeds, such as dandelion, are 'apomictic' and can produce seed without fertilisation. Others, such as shepherd's purse, are self-fertilising. In these cases it only takes one to tango, and the plant can reproduce even when isolated.

STRENGTH IN NUMBERS

A patch of ground as small as 30 sq cm can contain up to 5,000 seeds. Many weeds produce vast quantities of seeds.

Ephemerals produce less seed than annuals but have just as many offspring. Chickweed has a life cycle of only seven weeks and can produce up to 15,000 million plants a year. Getting about Weed seeds have evolved some fantastic ways of getting about. The opportunists take advantage of wind, water, fur, feathers, ants, bird droppings, shoes and just about anything else that you may care to mention.

• Wind weeds such as dandelions and groundsel have well-engineered parachutes to give them lift. Willowherbs have hairs to catch the wind, while the tree weeds sycamore and ash have winged seeds, the 'helicopters' that many of us played with as children. Minute seeds, like those produced by pearlwort, are easily spread by wind. Using these methods, sycamores have travelled up to 4 km, coltsfoot 14 km and ragwort over lOOkm.

• Inside animals Many weed seeds can survive passing through an animal's gut, e.g. charlock, redshank, fat hen, blackberry, and may even germinate more readily when they emerge from the other end. . .keep composting that manure!

• Outside animals Some weed seeds, e.g. cleavers, burdock, enchanter's nightshade, come equipped with hooks or spurs to grab onto and hitch a ride from passers-by. The seeds of shepherd's purse are covered in mucilage and stick easily to birds' feet and others in wet conditions. Many seeds have oil bodies, 'elaisomes', attached to them, e.g. speedwell, spurge, annual mercury. These are sought out by ants and dragged some distance before the oil comes off.

• Missiles Seeds that are shot out when ripe, e.g. oxalis, hairy bittercress, violet, ground elder, balsam, may not get very far but they do not have to rely on wind or animals. You may unwittingly give them a hand. Many a time ardent weeders spread hairy bittercress seeds when attempting to pull out its parents.

• Water Any seed that can float can spread by water. The prize must, however, go to ivy-leaved toadflax. This weed grows in walls and pokes its flowers out to the sun. When the seeds are ripe, the mature head turns to the wall and releases its seeds during rain, thus ensuring that it gets a good, moist seedbed in the cracks.

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