Problem plants
Introduction
Around 1,000 - 2,000 native species of plant
grow in West Sussex, ranging from the very common to the very rare.
Native plants have been established in this country for thousands
of years and grow in balance with their surroundings. However, a
few can cause problems for agriculture, livestock or structures,
and therefore need control in certain locations.
Non-native plant species outnumber native species and are those
that have been introduced, usually within the last few hundred
years, when plant collection, 'gardening' and 'landscaping' became
fashionable. Some, such as potatoes and runner beans, are very
valuable food plants and are not found away from where they are
planted. Others were brought here because they were considered to
be an enhancement to gardens or the landscape. Many of these plants
are now spreading across the countryside, changing the
characteristic landscape, causing deadly problems for our native
plants and animals, and in a few cases causing damage to
structures. Non-native species are one of the biggest threats to
our native species and a cause of loss of biodiversity.
These pages aim to help to raise awareness of some of the plants
that are causing serious problems. They should help you recognise
some of these plants, the problem each causes and action you should
take. It is not a complete list, and pages will be added
occasionally. Much more information can be found on the Internet,
although cautious judgement should be used to ensure such
information is correct, particularly with regard to Ragwort.
Herbicides usually need to be used to eradicate many non-native
plants, although these may be used only in addition to other
means.
Visit our Verges and
Grass Cutting page to see what to do if you find a problem with
grass cutting or weed control.
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Ragwort
Background information
Although Common Ragwort is a native plant of value to wildlife,
it is also one of the most frequent causes of livestock poisoning
in the West Sussex. Because of this we have always worked hard to
deal with it where it has been a problem, whether on our road
verges, small holdings or countryside sites.
We supported the Ragwort Control Act of 2003 which has now come
in to effect and provides for a Code of Practice to remind land
occupiers of their legal responsibilities to control Ragwort under
the Weeds Act 1959. 
The Code of Practice contains a wealth of useful information and
stresses the need for control where a high risk to livestock can be
demonstrated. You can download it, together with other documents,
including infestation complaints forms, from the Department
for Environment, Food and Rural Affairs web site.
Controlling Ragwort
- Managed grassland that is not overgrazed or neglected should
not suffer from ragwort infestation, so good, long-term management
is the best control method.
- In an emergency ragwort plants can be cut before seed
production takes place but cutting can actually make the plants
more vigorous. Hand pulling with gloves or digging with special
forks is effective when soils are damp and if the plants have not
flowered but it may need to be done for several years.
- Hand-held weed burners can be used on a small scale on spring
rosettes but may stimulate growth if the burn is not
effective.
- On a large scale, machine pullers or 'weed wipers' can be used
provided that the plants are taller than non-target plants.
- The most effective option is normally spraying with herbicides
like 2,4 D or natural products like citronella oil, although other
plants may be affected by spray drift in breezy conditions.
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Japanese knotweed
Japanese knotweed is an introduced plant that, in about 150
years, has spread to every county in the country, despite the fact
that only the female plant was introduced and fertile seeds are not
produced.
What does it look like?
In April, new shoots with bright green heart-shaped leaves grow
very rapidly, so a mature stand can reach 8-10 foot. In late
summer, small white flowers appear, before the plant dies back
again in the Autumn. In the winter the stems die back and turn
brown, but remain standing like Bamboo poles. Thus the plant is not
very noticeable in winter unless there is a large stand of it.
Why is it a problem?
- It smothers native vegetation
- It can cause structural damage to walls, path, buildings,
rivers and drains
- It is very very difficult to kill
- It produces massive underground stems
- It will grow in almost any soil - particularly in sunny
places
- A fragment of root about the size of a thumbnail is enough to
start a new plant
- It can cause structural damage to walls, path, buildings,
rivers and drains
- It will root from cut stems if these are left in contact with
the ground
What should you do if you see
some?
- If it's on someone else's land, inform the landowner, if
appropriate
- If it's on highway land in West Sussex, inform Highways and Transport
- If it's on development land, inform the local district or
borough council
- If it's on your property...
- If it's a small amount, and not growing near
water, treat it with Glyphosate (Roundup) weedkiller. It may take
several treatments. Please remember that it dies back in winter. Do
not compost or move the plant as this will encourage its
spread
- If it's a large area of growth, or near water, seek specialist
advice
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