Weeds
"Sweet flowers are slow and weeds make haste."

William Shakespeare. 

   

What is a Weed?

  
  • A plant growing where it is not wanted.
  • "A weed is a plant whose virtues are yet to be discovered" Poet Emerson 
  • One years seeding, several years weeding. 

   
Characteristics of an ideal weed. 
  
  • Fast growing and competitive
  • Spread by Rhizomes, Seed, Runners and Fragments 
  • High Seed Output
  • Self Pollinating
  • Germination requirements fulfilled in many environments
  • Tolerates a wide range of environments
  • Competes with other plant species by special means, chocking, competing for water and nutrients.
  • Allelochemicals, produce chemicals that stop other plants growing
  • Continuous production of seed (ephemeral)
  • Adapted for short and long distance dispersal
Weeds are either annual, re-producing from seed, or perennial. 
Annual Weeds
A plant that is an annual completes its flowering plant lifecycle in the space of one year it flowers at any time of year. 
 
It is essential to kill annual weeds before they seed. 
Annual weeds have a fibrous root system which makes them easier to control than perennial weeds. 
Weedkillers
Most useful weed-killers for killing established annual weeds, are:-
  • Glyphosate 
  • Paraquat with Diquat 
Germination can be controlled with:-
  • Simazine 
    
Manual Weeding 
    
Hoes
     
For best results weeds should be hoed on a good drying day, when they will die quickly. They should be cut off at about soil level so that the stems are separated from the roots. 
    
Digging & Forking 
  
By neatly inverting blocks of soil you can bury the weeds at a depth from which they cannot emerge. However this only works if the soil is fairly heavy and cohesive. On stony soil the weeds cannot be effectively buried and must be forked out. 
  
Hand weeding
  
It is best to wait until the weeds are quite large but not yet seeding and the pull them out as near to the ground as possible. 
  
Mulching 
  
This is normally applied in spring to warm moist soil, a layer of 2-3 inches thick (Further information to follow shortly.)
 
Perennial Weeds
  
A perennial weed has a continuous plant lifecycle, usually flowering in the months of June - October. Some could be classed as ephemeral which means they complete more than one lifecycle in a year.  
  
Perennial weeds seed too, but it is their root systems which cause most trouble. Unlike annual weeds, perennials have a well developed root, often creeping on the ground or surface. They usually possess a tap root (Dandelions) or rhizomes and runners (Thistles and Bindweed). 
  
The root must be completely removed or killed to prevent new plants regenerating. Even if a piece of root a couple of millimeters long is left in the ground this will then develop into a new plant.   
  

DO NOT PUT PERENNIAL WEEDS ON THE COMPOST HEAP. 
Weed Killers 
 
  • Glyphosate
  • MCPA
  • 2,4-D
  • SBK & Paraffin
  • Selective weed-killers
   
Manual Weed Killing. 
  
The only real manual weed-killing that is effective is digging out and picking the roots out by hand. 
  
Weeds
   
The following weeds are some of the most common that you will find growing. It will give you a general idea of how they spread, when they flower and how to control them manually or chemically.
  
Buttercups.
  
The most common type is creeping buttercup it can cover a large area at an alarming rate.  
  
Creeping Buttercup. Ranunculus repens
  
A very common weed, especially in lawns. It prefers heavy wet soils and flowers May - August. 
It spreads by runners which creep along the surface of the soil and roots at intervals which forms new plants and the process continues. 
  
They anchor themselves very firmly in the soil making them difficult to pull out by hand. Digging with a spade or fork makes it easier by hand. Fortunately it is sensitive to all selective weedkillers - weedkillers containing MCPA or 2,4-D. 
  
Lesser Celandine. Ranunculus ficaria (Figwort)
Not a major weed. It
prefers damp and shady sites and flowers March - May. 
  
It grows from underground bulbils and spreads by short creeping stems which grow from the bulbils.
  
It is very difficult to dig out and proves rather resistant to selective weed-killers. Apply a weed-killer on a warm day in late spring, either glyphosate or a weedkiller with two or more ingredients. 
Chickweeds - 
   
Common Mouse-Ear Chickweed Cerastium holosteoides
    
Major weed. Grows in all soils, prefers chalky dry soil, flowers between April - September.
  
This weed spreads by dense clusters of creeping stems with prostrate leaves which forms a large silvery mat. It has small white clustered flowers. 
   
Can be hoed, sprayed or dug and pulled out by hand. 
      
Selective weedkiller containing dicamba or mecoprop is effective. 
    
Common Chickweed Stellaria media
     
There are a few differences with this weed compared to the Common Mouse Ear Chickweed is the leaf is heart-shaped and stalked unlike the leaf on the Mouse-Ear Chickweed is oval and hairy plus the small white flowers have 5 divided petals with deep red stamens. It also flowers between February - November. 
    
Control is as above. 
  
Clovers 
    
Clovers are a major problem for many lawn owners. They prefer non acid and flower May - October. 
  
It is encouraged by a lack of water and nitrogen. 
    
Selective weed-killers are effective as well as a nitrogen rich fertilizer being applied every spring. 
  
White Clover Trifolium repens
   
Small clumps can be dug out quite easily by hand, alternatives are water well in dry periods and apply a selective weed-killer in June-July repeating every 6-8 weeks if needed. A nitrogen rich fertilizer can also be used.  
  
 Lesser Trefoil.  Trifolium dubium (Yellow suckling clover)
  
This clover is an annual, hand weeding small clumps can be effective, however it is more resistant to selective weed-killers than the White Clover, so repeat treatments at 6-8 week intervals will be needed.
Creeping Cinquefoil -  Potentilla reptans
     
Can be a nuisance weed. Spreads by creeping stems which root at intervals. Flowers June - September with a yellow flower.
   
Selective weedkiller containing dicamba or mecoprop is effective but a couple of treatments will be needed. 
  
Dandelion Weeds
    
There are two common dandelions:-
Dandelion. Taraxacum officianale
  
This is a perennial weed. You can hand weed but any bit of root  left in the soil will produce a new plant. 
Spreads by seed and bits of root left in the ground. 
You can spot treat with chemicals (Glyphosate stick) or for a large area spray with a selective weed-killer. 
  
Cats-Ear. Hypocharis radicata
   
A perennial weed, flowers May - September. 
 
Daisy. (Days eye) Bellis perennis
More of a problem in lawns than borders. Flowers March - November. 
  
Spreads by creeping stems. 
 
Can be hand weeded, however it is easy to control with a selective weed-killer, containing two or more ingredients, for larger area. Repeat treatment every 6-8 weeks if necessary. 
  
Docks & Sorrels
  
There are two common docks which grow in our gardens. 
 
Sheeps Sorrel. Rumex acetosella 
 
A problem in borders where the soil is not compacted. Flowers May - August. 
  
Spreads by creeping stems. 
  
Can be hand weeded when only a handful are present, make sure you dig all the roots out, With larger infected areas chemical control is more practical. Weed-killers containing MCPA or 2,4-D will be effective, apply in late spring and repeat, if necessary, 4-6 weeks later. 
  
Common Sorrel  - Rumex acetosa
 
Common weed. Flowers May - June 
 
Control is the same as above. 
   
Japanese Knotweed  Fallopia japonica Mexican bamboo, Japanese fleece flower
  
Japanese knotweed was believed to have been introduced to Britain by the Victorians around 1825. Since which time it has become a major problem. 
  
It spreads via an extensive and very rapidly growing rhizome system. New plants can grow from just a tiny fragment of root. Alot of infestations can be seen by rivers and streams as the roots are washed downstream and start growing on the banks. 
  
The roots can go down as far as 2m and can spread from between 7-10m from the parent plant. 
   
It is an offence to plant or encourage the plant to grow in the wild. 
  
It is also classed as a "controlled waste" so must be dispersed of safely at a licensed landfill site.  
  
 for small infestations there are three main ways to try and combat the problems:-
 
  • Cutting
  • Digging & Pulling
  • Injection 
 
CUTTING
 
Cut the stems to roughly 12 inches in height, or between the 1st and 2nd node on the stems, ensuring that you leave some of the foliage on the plant. Then apply a glyphosate weedkiller to the leaves and plant and cover with black plastic bags. 
 
The weedkiller will be translocated through the plant to the roots and Knotweed is weakened by lack of light. 
  
DIGGING
 
If it is only a minor infestation you could try digging and pulling the weed out, but don't forget that the roots go down 1.5 - 2m. and all the roots need to be taken out otherwise it will grow again. 
  
INJECTION 
 
Cutting the stems and injecting a weedkiller, glyphosate, into the inside of the stem is being tried out in various parts of the country with positive results. 
 
For large infestations in fields that you want to build on you will have to contact a company who specialises in getting rid of Japanese knotweed, as well as working closely with the Department of Environmental Health due to the amount of chemicals needed to be used (water run off) plus the disposal of the plant. 
Plantains 
 
Plaintains grow everywhere, they are easily identifiable with their leathery and prominently ribbed leaves with erect spikes of small flowers. 
 
The three most common are:-
 
Greater Plantain. (Broad Leaved Plantain) Plantago major
Very common weed especially in compacted soil. Flowers May - September. 
  
If only a few are present they can be hand weeded with a fork. They have very strong roots on them when trying to just pull out by hand. All plantains are very sensitive to selective weed-killers containing MCPA or 2,4-D. A single application should be sufficient.  
   
Hoary Plantain (Lamb's tongue) Plantago media 
  
Very common weed. Prefers chalky and infertile soil. Flowers May - August. 
   
Control is the same as above. 
 
Ribwort. Plantago Lanceolta 
  
Very common weed. Prefers non-acid soil. Flowers April - September. 
 
Control same as above. 
 
Speedwells
There are two nuisance speedwells.
Slender Speedwells (Round-leaved speedwell) Veronica filiformis
    
Major weed. Has a small mauve coloured flower on a thread like stalk.. It prefers damp soils. Flowers April - June.
   
It spreads by creeping stems, rooting at intervals to form new plants. 
 
Unfortunately this weed is not resistant to most selective weedkillers. The selective weed-killer ioxynil was used to control this weed but is no longer available. A product containing dicamba or mecroprop could be used but constant repeat applications are needed. Hand weeding really is the only control. 
 
Germander Speedwell  (Bird's eye speedwell) Veronica chamaedrys
   
Common weed. Small blue-coloured flower with a white eye on a thread like stalk. Prefers damp soil. Flowers April-June. 
    
Spreads by creeping stems, as above.
  
Control is the same as above.
  
Thistles
 
Thistles can be a nuisance in the garden
  
Creeping Thistle Cirsium arvense
 
Common weed. Has the infamous lilac flower head and spiky leaves. Flowers between June - September. 
  
Spreads by its creeping roots. 
  
Can be controlled by hand weeding, spot treatment or spraying with a selective weedkiller containing dicamba or mecoprop. May need applications every 6 - 8 weeks.