Weeds – knowing the Enemy

What makes a plant a weed?

  • only the fact that it’s growing where you don’t want it to grow, literally – it is an invader on your lawn.

It takes a very special plant to be a weed in your lawn. Most plants (besides grass plant) can’t handle mowing – you cut them and they die. Unfortunatelly, there are some hardy varieties that can live and grow just like your grass. Weeds are categorised into groups of plants with similar characteristics. They are sorted by how long they live, what they look like, and their primary growing season.  Different weeds have different life cycles and they are classified as annual, biennial and perennial.

  • Annual Weeds – live out their lives in one year (grow, produce seeds and die in one season); the seed from the plant germinate and grow next year, conitinuing the cycle and we need to remove them before they begin growing from seed.
  • Biennial Weeds – have a two – year life cycle (first year – grow, second year – produce seeds and spread)
  • Perennial Weeds – they live for more than two years and do not need to reseed themselves every year

Most commons weeds in English turf

Daisy (Bellis perennis)

Perhaps the most common lawn weed to be found. The Daisy is a perennial plant with spirally arranged, spoon shaped leaves which form a dense mat over the lawn surface. White flower Ray florets with bright yellow centre and closes at night (old name “day’s – eye’).  The Daisy will grow in any soil conditions and especially in closely mown turf. It is also very effective in flowering and seeding and its flowering period is between March and November.

THE CONTROL of daisy is easy and need no allow for this weed to spread and become a nuisance. It is relatively easy to remove the plant by hand weeding, but the most effective control will be gained by application of herbicides if the weed infests large portions of the lawn. The active ingredients: 2.4-D, MCPA with dicamba or Mecoprop-P will control this weed, although repeated application may be required for total eradication.

Yarrow ( Achillea millefolium)

This is a very common weed, which spreads by the production of underground stems. The leaves are dark green, finely divided and have a fern- like appearance. Yarrow will occur on all types of soil but thrives under dry conditions. Flowering period: June – August. The flowers are small and white borne in a flat – topped cluster. The flower will not form when the grass is regularly mown.

THE CONTROL of yarrow is notoriously difficult – no single treatment will control it. During dry weather condition the plant can be pulled out of the lawn by hand. There are many herbicides to which yarrow is not susceptible, so those chosen must contain 2,4-D, MCPA with dicamba, or Mecoprop-P

Dandelion (Taraxacum officinale)

This plant is found under all soil conditions. The leaves are joined directly to its thick fleshy tap root. They have a tooth like lobe, they are hairless and grow close the ground level. Flowers are single and large and appear from March until November, but mostly do so during the spring. If the dandelion is allowed to produce seed heads – due to infrequent mowing- the ultra light weight seeds are easily dispersed by the wind to other parts of the lawn.

CONTROL: hand weeding is possible, but any bit of remaining root in the soil will produce a new plant. They can be a serious nuisance in many lawns. Chemical spot treatment is better. Repeated application with any of the active ingredients 2,4-D, MCPA with dicamba or Mecoprop-P will control this weed.

 

 

Creeping Buttercup (Ranunclus repens)

This is a creeping perennial plant most commonly found on heavy soils. It spreads by the production of long stolons. The plant flowers from spring to late summer and it presents well known yellow petalled buttercup flower head. Each leaf bears 3 lobes – upper lobe is stalked. These lobes are deeply toothed and hairy. Creeping Buttercup can be a serious problem if neglected.

CONTROL  best managed with hand weeding thought applications of fluroxpyr, clopralid and MCPA.

 

 

 

 

Greater Plantains (Plantago major) / Broad – Leaved plantain

This is a very common weed which occurs in compacted areas. The leaves are broadly ovate, stalked and lined with five or more longitudinal nerves. It produces long, greenish-gray flower heads from May until September. This plant produces masses of seeds that can re-infect the lawn in later years. Isolated plants can be removed by hand weeding with a small fork when grass and weeds are actively growing.

CONTROL: the active ingredients 2,4-D, MCPA with dicamba or Mecoprop-P will all control this weed easily.

Bird’s foot Trefoil (Lotus corniculatus) / Bacon and Eggs

This is also one of major weeds on English lawns and its favoured situation is non-acid soil. It produces a thick fleshy rootstock and occasionally short stoloniferous growths. This plant doesn’t root at intervals like white clover and can form quite large patches. Each plant is anchored by a deep taproot. The flower head has 5-8 pea-like yellow streaked red flowers. Flowering period is from May until August. Each leaf bears 3 leaflets, with 2 leaflet-like structures at the base.

CONTROL: Bird’s foot trefoil is less sensitive to selective herbicides – a repeat treatment after about 6 weeks will be necessary. For best control only use the active ingredients ioxynil and/or Mecoprop-P that can effectively kill it. Hand weeding is almost impossible as this weed can grow in between and around the grass leaves.

Pearlwort (Sagina procumbens)

This is a small tufted perennial which is common in turf. The plant produces a tiny dense patch which spreads by production of slender stolons. The leaves can be in two forms. On small plants they tend to be in rosettes, whereas in established specimens they are produced along the stolons. Pearlwort produces tiny flower on top of a thin stalk and white petals may or may not be present. The flowering period is between May and September. This plant will appear in all soil conditions.

CONTROL:  This is an easy weed to control, so it should be not allowed to spread and become a nuisance. Selective weedkiller with one or two active ingredients is an effective method. One application should be enough, but pearlwort will soon return unless you feed the grass and avoid mowing too closely.

White Clover (Trifolium repens)

This is a creeping plant which is particularly common on clay non-acid soils. The leaves are produced on long stalks and consist of three rounded toothed, leaflets. The flowers are white or rosy in colour and are produced between the Spring and Autumn. White clover is widespread in pastures and meadows, frequently cut grass verges and lawns. It is absent from tall grass. This plant is highly variable species with many varieties and over 70 commercial cultivars. White clover has been an important constituent of food since the 17th century. Its main benefit is that it can convert atmospheric Nitrogen into plant usable form, reduces N fertiliser use and improves soil structure. As this weed can grow between and around the grass leaves it is almost impossible to remove by hand. The seeds it produces can last 20 years in the soil.

CONTROL of this weed is never easy and, although most lawn herbicides will have some effect, white clover is resistant to them. For best control only use the active ingredients ioxynil and/or Mecoprop-P and these will need repeated treatments for a number of years before good results are seen.

Ribwort Plantain (Plantago lanceolata)

Ribwort is a common perennial weed and it is present on non-acid soils all over the UK. This plant survives well in lawns even where the lawn is mown at a short height of cut. The leaves are simple, lanceolate, ribbed and are produced in type of rosette. The flowers which are produced from April to September are wind pollinated and are formed on long slender stalks. This weed it may not flower at all in closely mown swards.

CONTROL  is best managed by hand picking out the germinating plants early in the spring. Applications of MCPA, Mecoprop-P and Dicamba will also control this weed adequately.

 

 

 

Speedwells (Veronica spp.)

Several types of speedwell species invade home lawns. Some are annual plants that reproduce from seed and others are perennial plants that can reproduce by seed, rhizomes and creeping stems. All are low growing with small leaves. Perennial species are generally more difficult to control.

CONTROL: a combination of proper cultural practices, adequate nutrition and a progressive weed control program that may include repeat applications of government regulated weed control materials will help to control these weeds over time. It may require several years of effort by a lawn care professional and the homeowner before adequate control of these weeds is achieved.

Promoting a healthy lawn is the best defence against having severe weed problems. Proper mowing and watering, regular fertilisation and core cultivation when necessary are key ingredients in building a healthy lawn. The use of government regulated pest control materials, as tools to control weeds and other pest problems will help to protect grass plants and ensure vigorous growth in a lawn. Most broadleaf weeds that invade lawns can be effectively controlled with the use of selective weed control materials that are currently available. These products are referred to as selective because they only affect the weeds and do not harm the grass plants in a lawn. There are, however, some weeds that are extremely difficult to control and some that cannot be controlled with the use of these materials. Special attention and care is often needed to control these persistent weeds. Some difficult to control weeds found on home lawns are listed above. If weed problems such as these exist on your lawn, your local Weed Man can assist you with a program that will help reduce or eliminate this problem over time.

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