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Weed watch: guide to identifying and removing weeds

Written by: phs Greenleaf

Writes the best tunes

Weeds have earned themselves a bad reputation. When most of us see them popping up in our paths, borders and flowerbeds, we remove them immediately to stop them overshadowing our other flowers and ruining the look of our expertly crafted planting displays. However, it hasn’t always been this way for weeds. Many of the most rapidly spreading weeds have moved from being admired and favoured plants by horticulturists, to being vilified as unwanted nuisances that compete with other flowers.

Some may call them misunderstood, but weeds need to be quickly removed and controlled to prevent them from causing harm to your other plants. However, the problem with weeds is that they love the same things that most of your flowers and plants do, and they use them to their advantage. Sadly, this means that they steal vital sunlight, water and nutrients from the greenery you actually want to grow. Additionally, weeds have the upper hand as they thrive in harsher conditions, such as hard, compacted soil, or wet, loose soil. They can also grow in shaded locations, and areas where grass may be thinning and patchy. This can be damage from heavy footfall, disease or pests.

Additionally, weeds are master contortionists as they will grow in any space they can fit their way into! This is why it isn’t unusual to see them suddenly pop-up in the cracks between pavements and paths.

Why is it so important for businesses to keep on top of their landscaping and control weed growth? It couldn’t be simpler; you want to make your building as inviting as possible, ensuring you give the right first impression to your visitors and potential customers. An unruly, overgrown exterior space is going to give the appearance that you don’t care about how your premises look, and this could translate to your future customers thinking that you may adopt the same attitude towards the products or services you provide them with.

To keep your business grounds and garden looking great all-year-round, phs Greenleaf have used their expertise to produce a handy guide to identifying, controlling and removing some of the most common weeds…

Japanese Knotweed

Japanese Knotweed is one of the most invasive weeds in the UK, having the ability to rapidly grow up to 10cm a day in warm weather. It can reach a total height of four metres and its roots can burrow up to 3 metres deep in the ground, invading and causing damage to rivers, pavements and buildings. One of the reasons Japanese Knotweed is so hard to control is because it was introduced to the UK in 1850 without the psyllids (insects) that keep its growth under control.

What does it look like? Japanese Knotweed can be a tricky weed to identify as its appearance changes from season to season. It also share similarities with a number of other plants throughout its lifecycle. When the shoots first appear in the spring months, they look similar to asparagus, although they could be mistaken for bamboo as it grows taller and the leaves start to sprout. In the summer, the plant can be identified by its distinctive clusters of small-creamy white flowers and flat green leaves. These grow in a zig-zag shape and are a unique heart/shovel shape.

How to remove it: Japanese Knotweed can be treated with a chemical called Glyphosate or by digging out the growth. This weedkiller should be applied directly to the foliage. To dig the weed out from the ground, you’ll need to ensure that any old stems from the previous winter are cut away, and that you remove the rhizome-clumps which the roots sprout from. If the plant isn’t completely removed, it will just continue to grow back. When removing Japanese Knotweed, remember that the best time of the year to treat it is during the summer months when its flowering.

Broad-leaved Dock

Broad-leaved Dock is a native weed that can be found in many areas of the UK, including woodlands, farmland, waste grounds and gardens. It particularly thrives in high nitrogen environments, and some of the areas that are most commonly affected are those that have recently disturbed grounds or rough grass. It has the potential to spread considerable distances thanks to its seeds being dispersed by wind, water and other sources. It’s also slightly poisonous, causing mild dermatitis in humans.

What does it look like? Broad-leaved Dock can be identified by its typical height of around 1m, as well as its leaves and seedheads. Look out for the spiked seedheads where clusters of small reddish-brown flowers grow between June and October. Docks’ leaves are also a key feature. They are green, oval in shape, and large in size, growing up to 25cm long.

How to remove it: Docks are best removed and controlled with chemical methods. A non-glyphosate weedkiller can be effective for treating established docks, and this should be applied from the middle of summer onwards. If you’re worried about damaging the surrounding grass or lawns, then choose a selective weedkiller instead.

Giant Hogweed

Giant Hogweed is extremely harmful to both the environment and human health. As well as impacting the growth of native plants, the chemicals in the sap causes photosensitivity, or sensitivity to sunlight. This means that when the plant is touched

by human skin, it causes severe burns and blistering of the skin that can result in pigmentation and scarring. First brought to the UK and Europe in the nineteenth century, it became a key feature in ornamental gardens, but it quickly spread into the wild.

What does it look like? At first glance, Giant Hogweed is similar in appearance to cow parsley (another plant which isn’t harmful to human health). This is because both plants have white, flat-topped flowers which face upwards and are held in umbels. However, there are some key differences to look out for. Giant Hogweed has finer, more feathery leaves that are a darker shade of green, and these have purple blotches on their stems. Another distinctive feature of this invasive plant species is its large size; it can reach a height of 5 metres with a spread of 1-2m.

How to remove it: Giant Hogweed can be removed through chemical and non-chemical methods, but if you do decide to use chemicals, a Glyphosate-based weedkiller will be the most effective. You should spray the young foliage in May, and retreat the area in either August or September if there’s regrowth. Removing the weed without chemicals should also be done in May when the soil is moist as the seeds and young plants can be pulled from the ground by hand. Just don’t forget to wear gloves and suitable face coverings to prevent the sap from coming into contact with your skin!

Himalayan Balsam

Himalayan Balsam is an attractive invasive species that has become Britain’s largest annual plant since it was first introduced to the UK in 1939. Often growing near waterways, it damages the environment by eroding riverbanks and causing flooding. Due to the fact that this ornamental plant can grow up to 2.5m tall in some cases, it also prohibits the growth of other plants by shadowing them. It’s an offense to allow Himalayan Balsam to spread into the wild, so you should remove it from your premises.

What does it look like? This invasive plant is attractive in appearance and it has a few defining features all-year-round.

These include its great size and serrated leaves. These are green in colour, are typically around 5-8cm in length, and they grow from the stem joins in groups of 3-5. However, the easiest time to identify Himalayan Balsam is between the months of June and October. This is because it produces clusters of pink and purple toned flowers. These can sometimes be white, but this is rare. The flowers are supported by green fleshy stems that become red towards the end of the year.

How to remove it: Himalayan Balsam can be effectively removed with non-chemical controls. Because it has shallow roots, it can be pulled or dug out of the ground. You can also inhibit its growth by cutting the plant or covering it with a layer of mulch. If you choose to cut the growth, this will need to be done regularly for around three years to completely eradicate it. Alternatively, use a contact weedkiller that contains acetic acid, or a systematic weedkiller that contains glyphosate. A contact weedkiller should be applied before it flowers, and a systematic weedkiller should be applied in early flowering stages.

Creeping Buttercup

Creeping Buttercup is a weed that most of us are familiar with as we used pick them from our gardens and put them under our chins to see if we liked butter! However, you should remove them from your business grounds and gardens as they spread rapidly in flowerbeds, lawns and borders. They also tend to favour areas with moist soil, so their presence could indicate that you need to improve the structure and drainage of your soil.

What does it look like? We all know buttercups for their delicate and eye-catching flowers, which are glossy and bright yellow in colour. These typically bloom from March to August. When the flowers are dormant, you can identify buttercups by their leaves. They grow in three toothed leaflets and are dark green with lighter patches.

How to remove it: The best way to control the growth of Creeping Buttercup is to improve the quality of your grass and soil drainage. You can improve drainage with aeration, and promote healthier grass growth by adding lime and fertilising your lawns as needed. Buttercups can be removed by applying a suitable herbicide, or they can be dug out with a sharp trowel.

For more invasive weeds like Japanese KnotweedHimalayan Balsam, and Giant Hogweed, removal and control can be made easier with the help of a specialist company. At phs Greenleaf, our trained technicians are fully equipped with the knowledge to remove these weeds, and they will assess the area to provide practical recommendations to control them. Contact us to find out more about how we can help you keep your grounds looking their best!


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