WEEDS – THEIR CONTROL & USES

CONTENTS:

1. BEST PRACTICE

2. PERENNIAL WEEDS

3. ANNUAL WEEDS

4. CONCLUSION

1. BEST PRACTICE

Too often I have seen examples of organic gardens overrun with both annual, and worse still, perennial weeds like convolvulus, couch grass, oxalis etc. There is an acceptance by many who attempt to grow organically that this is acceptable and even natural. Worse still I have seen some community gardens and other organic show gardens disorganised and full of weeds. For anyone who is thinking of growing food organically and sustainably, visiting one of these gardens is an immediate turnoff and very bad publicity!

Organic, sustainable and the other biological forms of gardening and farming, already discussed, are not about anarchic, lazy muddled thinking and practice; they should be beacons of best practice, where weeds have their place in designated areas as part of the rich mix, but are not taking control and smothering and out-competing crops for nutrients and water and producing seeds which will cause even more problems in the future. If you want to be lazy, buy poisonous herbicides and wipe out everything except the crop you want to grow. Yes, sustainable and organic weed management takes more intelligence, creativity and hard work – TOUGH!

Growing food sustainably requires more knowledge, more expertise, and more effort than conventional practices. Nobody wants the uniform, obsessional, sterile, weedless mono cropping that has become all too common, but that is no excuse for flaky ideas and practice. Sustainably run gardens and farms, especially those open to the public, should be beacons of best practice, which wow visitors and inspire them to grow healthy food themselves. If we are going to win over the mainstream we need to get our act together.

2. PERENNIAL WEEDS

These weeds are the most tricky to manage, but they can be controlled and they definitely have their uses. If they are not controlled, especially in more intensive growing areas, and particularly where perennial crops are to be grown, they will continue to be a nuisance, unless thoroughly got rid of in the first place. The roots of perennial weeds include, convolvulus and couch grass roots, oxalis bulbils, dock roots and dandelion roots.

Fortunately perennial weed roots are full of valuable plant nutrients and are therefore very useful if recycled in a safe way. Do not put them in the compost heap, you will just be spreading them everywhere! Somebody tried composting convolvulus roots over several years at the community gardens we were involved with, thinking they would be killed in the composting process. As a result the whole property was riddled with convolvulus and took many months to rid the soil of this pest.

Kill the perennial weed roots (or bulbils) first by putting them in a tub, covering them with water, putting a lid on and leaving them to rot for a minimum of 6 months, or better still 12 months. Then add the mineral rich water and the dead roots to the compost heap, which are full of plant nutrients.

Alternatively, place the roots in a black waste bag with a sprinkle of water; and when reasonably full, tie the top and place the bag in an odd corner, or building in the dark for 12 months, they should then be dead and can be added to the compost heap.

Just be aware, that both couch grass and convolvulus roots can look dead, until you put them in the compost heap, then they can spring to life if you have not waited a minimum of 6 months – so – better make it 12 months and be sure!

Convolvulus:

Flower leaves and tendrils

Flower leaves and tendrils

If you want to grow crops intensively, then you need to clear the ground of this very persistent weed.

This involves trenching systematically across the patch, turning the soil over with a fork and carefully extracting the thick white roots. 

Long brittle tenacious roots

Long brittle tenacious roots

Convolvulus roots break easily and might go quite deep, so follow them down until you have every bit out. If they break off, the bit left in will regrow. Unless you are a miracle worker, there will be bits of root left in the soil. Leave the patch unplanted and unsown for at least two weeks and you will find new shoots coming up and then you can trace them down to the roots left in and dig them out. Also if there are seeds in the soil these will germinate and will need to be extracted. When there is no more growth, you can cultivate, plant and sow.

Couch Grass:

The leaves and flower heads

The leaves and flower heads

There is a good chance that couch grass will be growing with convolvulus.

Even if it’s growing on its own, follow the same procedure as for convolvulus.

Couch grass is not as difficult to get rid of, but the same rules apply – leave even a tiny bit of root in and it will grow again.

The cream-coloured knobbly roots

The cream-coloured knobbly roots

Oxalis:

Oxalis has little bulbils that break off very easily when you try to dig the plant out. Use a large hand trowel to get right under the plant and bring the soil ball out onto the surface where you can sort through it with your fingers to extract the little bulbils.

The white flowers & clover-like leaves

The white flowers & clover-like leaves

The little bulbils

The little bulbils

Dock:

Dock does not run like convolvulus and couch grass, but it has a deep taproot and produces hundreds of seeds if allowed to flower.

Use a garden spade to dig deep enough so as not to break the root when digging it out, otherwise it will grow from the bit left in.

Large spear-shaped leaves & flower-heads

Large spear-shaped leaves & flower-heads

The tough fleshy roots

The tough fleshy roots

Dandelion:

Dandelion is another perennial plant with deep roots and many seeds that tend to develop very quickly after flowering.

So, pick off the flower heads to stop them seeding.

Leaves & Flowers

Leaves & Flowers

Rough brown roots

Rough brown roots

USES

So, what to do with these difficult perennial weeds and roots when they have been dug up? As already discussed in the section on Bio-dynamics, one of the fascinating things about wild plants is that they often contain minerals that are lacking in the soils in which they grow. Also, the storage roots and bulbils of the weeds above, have extracted valuable minerals from the soil in which they are growing, so it would be a real shame to put them in with your weekly municipal trash to go to landfill, but we also don’t want to put them in the compost heap unless they are definitely dead, otherwise they just get spread around the property, so we need to kill them first before composting them.

For a larger property, have at least two, 200-litre (50 gallon) barrels with lids, preferably with large plastic taps fixed near the bottom. Raise the barrels up on blocks so you can get a bucket under the tap. Cover the back of the tap inside the barrel with some material or sacking, held down with a stone, to stop the tap getting blocked. Add your perennial weeds and roots to the barrel and cover with water and place the lid on. Every time you add some more roots, add more water.

When the first barrel is full, leave for at least 6 months, preferably 12, by which time the weeds will have drowned. Then start filling the second one. Use the nutrient rich juice on your compost heap. When drained off you can tip out the dead roots, which can then be added to the compost. Treat these weeds as valuable miners, gathering essential nutrients and trace elements that can then be fed back to your crops.

MEDICINAL USES 

Couch Grass (Agropyron repens) – The roots are rich in Phosphorus and other plant nutrients, which is a very useful addition to the compost heap, once killed. Fresh couch grass roots are also used in herbal medicine, (see the section: ‘Growing Herbs’ - Couch Grass).

Dandelion (Taraxacum officinale) – The flowers attract bees. Rich in minerals, young dandelion leaves blend wonderfully into salads and the roots can be cut up into small pieces, roasted and ground as a coffee substitute. Medicinally, (see the section: ‘Growing Herbs’ - Dandelion).

3. ANNUAL WEEDS

Most annual weeds are not difficult to keep under control and they are beneficial when added to the compost. Many are useful, either as food, or for their medicinal properties.

Apart from traditional hoeing of young seedling weeds in dry weather, one of the best ways to control annual weeds is to use mulches. Mulches are not fool-proof, but they will greatly reduce annual weed growth. First clear the area of weeds, and then add the mulch. A few will grow through, but are easily dealt with by pulling or digging them out.

For paving, paths or other areas that need keeping weed-free you can use a homemade spray:

• 4 litres white vinegar

• 2 cups Epsom salt (Magnesium sulphate)

• ¼ cup eco-washing up liquid

USEFUL WEEDS:

Fat Hen:

The flowers attract hover-flies and bees. Chickens like it – hence the name. It is high in iron, protein, calcium and vitamin B.

The leaves and young shoots may be eaten as a leaf vegetable; either steamed in its entirety, or cooked like spinach. Each plant produces tens of thousands of black seeds. These are high in protein, vitamin A, Calcium, Phosphorus, and Potassium. Quinoa is a closely related South American species, which is grown specifically for its seeds.

The powdery pointed leaves

The powdery pointed leaves

In the past, fat hen was grown for its seeds and in India the plant is still used, both for the leaves and seeds. It is popularly called bathua and is used in dishes such as Sarson Da Saag, soups, curries and in Paratha stuffed breads, especially popular in Punjab. The seeds or grains are used in phambra or laafi, gruel type dishes in Himachal Pradesh.

Chickweed (Stellaria media)                                       It has a good taste and is a useful addition to salads. It is high in iron and copper and a great food for young chicks – hence the name.

Medicinally: Part used – leaves and stems. It is a healing demulcent, and possesses remarkable drawing powers, absorbing quantities of impurities when applied to the skin. This small herb possesses many of the healing properties of that famed remedy of the American Indians, Slippery Elm tree bark. It is a soothing and healing agent for the whole digestive system. Good to cure ulcers of the stomach and elsewhere, indeed for all internal inflammation, from bowels to lungs; also good for colitis. A cure for many types of skin sores.

White Clover (Trifolium repens)

This is a common weed with tenacious fibrous roots.

Even though it can be a bit of a nuisance weed, it is a nitrogen fixer and contains calcium, potassium and magnesium and is a useful addition to the compost heap.

Medicinally:

It has some of the benefits that red clover has, but I would suggest using red clover for its famed medicinal properties rather than white.

Ground Ivy (Glechoma hederacea)

A common weed that attracts bees and predatory wasps to its flowers.

Medicinally:

Ground ivy has been used in the traditional medicine of Europe going back thousands of years. It is a diuretic, astringent, tonic and gentle stimulant. It has been used to treat inflammation of the eyes. Other traditional uses include a cough remedy and to relieve congestion of the mucous membranes and to treat bronchitis.

Goose Grass, Cleavers (Galium aparine)

A common weed that sticks to clothing and passing animals. It is rich in minerals.

Medicinally:

It is refrigerant, laxative and tonic and is much used in diseases of the urinary system.

Its refrigerant properties make it excellent for fever treatment and for skin troubles, including dandruff. Is rich in silica, which exerts a powerful influence on hair and teeth.

Taken internally as a hair tonic and to check tooth decay.

Speedwell (Veronica officinalis)Common.

Medicinally:

Removes excess mucus from the body, sooths all internal tissues, and provides a tonic and blood cleansing tea that stimulates the gastric juices.

For the treatment of cough, bronchitis and other lung ailments.

Externally, for skin inflammations.

Fumitory (Fumaria officinalis)

Very common garden weed in New Zealand.

Medicinally:

Its chief value is as a cure for all ailments of the liver, also for the treatment of skin diseases. As a digestive tonic. Also to allay biliousness, vomiting, and for general stomach disorders. Of course there are many more annual weeds that will be valuable in the compost, or can be used for medicinal purposes, but here are just a few of the most common ones. I will leave it to you to discover many more and their uses.

4. CONCLUSION

By now you will have a better understanding of both the problems and benefits of weeds. Weeds will always be with us. They can tell us about the nature of the soils in which they grow. They often contain nutrients and trace elements that are lacking in the soil in which they are growing and are therefore valuable in restoring nutrient balance by recycling them via the compost heap. Their flowers can attract bees and beneficial predatory and pollinating insects and they often have beneficial medicinal properties and some are a good addition to the salad bowl.

They can definitely be a valuable addition to the bio-diversity of any property, as long as the more tenacious of them are not allowed to take over. Some of the most difficult perennial weeds need tightly controlling and even eliminating where more intensive crops are grown, but even they have a value when killed and recycled through the compost heap, or used as medicine. All in all, it is counterproductive to see weeds as the enemy with whom you must wage a permanent war. They are just trying to survive and prosper, but you are trying to create a balanced, healthy and beautiful food growing environment. You as gardener, horticulturist, or farmer have to treat weeds, especially the difficult ones, as wayward children – you love them and value them, but have to insist on boundaries beyond which they do not stray.