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Weed watch: guide to identifying and removing weeds

Written by: phs Greenleaf

phs Greenleaf has been providing planting and landscaping services to businesses for over 25 years, including indoor and outdoor plants, artificial and live planting, living walls, grounds maintenance and Christmas trees and decorations.

Weed watch: guide to identifying and removing weeds

Last updated: 15 March 2021

Most common weeds have earned themselves a bad reputation. When they start 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. But it hasn’t always been this way for weeds.

What are weeds?

Many of the most rapidly spreading and common 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.

Weeds usually 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.

They are also 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 permanently removing some of the most common garden weeds, including:

  • Japanese Knotweed
  • Broad-leaved Dock
  • Giant Hogweed
  • Himalayan Balsam
  • Creeping Buttercup


What is 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 Japanese Knotweed look like?

Japanese Knotweed can be a tricky weed to identify as its appearance changes from season to season. It also shares 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 Japanese Knotweed

Japanese Knotweed can be treated with a chemical called Glyphosate or by digging out the growth. This weed killer 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.

What is 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 Broad-leaved Dock look like?

Broad-leaved Dock can be identified by its typical height of around 1m, as well as its leaves and seed heads. Look out for the spiked seed heads 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 Broad-leaved Dock?

Docks are best removed and controlled with chemical methods. A non-glyphosate weed killer 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 weed killer instead.

What is 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 Giant Hogweed 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 Giant Hogweed

It can be removed through chemical and non-chemical methods, but if you do decide to use chemicals, a Glyphosate-based weed killer 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.

What is 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 Himalayan Balsam 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.

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 Himalayan Balsam

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 weed killer that contains acetic acid, or a systematic weed killer that contains glyphosate. A contact weed killer should be applied before it flowers, and a systematic weed killer should be applied in early flowering stages.

What is Creeping Buttercup?

Creeping Buttercup is a weed that most of us are familiar with, picking them to put 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 Creeping Buttercup 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 Creeping Buttercup

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.

A safe way to remove invasive species

For more invasive weeds like Japanese Knotweed, Himalayan 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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