Experts warn of 'thuggish' plants that can spread out of control

Wisteria Tunnel at Pinces Gardens in St Thomas, Exeter
Wisteria is beautiful but can be harmful if not managed correctly -Credit:DevonLive/AlexRichards

There are plants, shrubs and trees that might be lovely to look at but could be more trouble than they' are worth in your garden. These are the aggressive 'thugs' of the horticultural world and should either be avoided or managed carefully to save yourself from serious problems.

Species such as English ivy, wisteria, juniper and eucalyptus can be invasive, grow uncontrollably and even pierce through walls. Of course, depending on your landscaping needs, aggressive plants are not always bad.

However, to those with a small, organised garden space, aggressive 'thuggish' plants can quickly become a nuisance. They can not only cause damage to your garden but can also damage your home, warned Melvin Cubian, gardening expert at PlantIn. Below we have detailed five species that could cause you problems.

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English ivy

English ivy grows by spreading runners which climb over and smother anything and everything in their path including buildings, shrubs, and trees.

If you're a homeowner, you really do not want this plant climbing up your walls. The rootlets will burrow into walls, eventually weakening them to the point of collapse, reports the Express. As a ground cover, the quick growth and dense cover shade out native plants and suppress their growth.

Melvin said: "This trailing vine has an invasive habit, penetrating on rocks, walls, and virtually anything that comes on its path. Armed with suction cup-like puncturing roots, it clings to other plants and can constrict small shrubs and less aggressive species."


Wisteria is a gorgeous woody vine that blooms with drooping clusters of bluish purple flowers in spring but be prepared for potential trouble. While it may be a sight to behold, with its vines adorning walls and other structures, the weight and size of these vines can become problematic. They can infiltrate cracks and crevices, causing damage to the exteriors of homes, garages, and sheds.

Melvin warns that this plant "grows uncontrollably and can pierce through the walls", gradually weakening its structure, saying: "In a poorly maintained garden, it spreads violently and competes with smaller plants for sunlight and nutrients."

Gardeners should brace themselves for extensive pruning and maintenance when dealing with wisteria, particularly the Chinese variety.


Eucalyptus are towering trees with shallow, spreading roots adapted to the harsh growing conditions in their native Australia. While this may not pose an issue there, in UK gardens the shallow root depth of eucalyptus can become problematic.

Melvin stated: "While this fragrant tree sets a calming ambience to gardens, it is a fast-growing tree species that can damage the house's foundation and suppress plant growth with its allelopathic properties."

For those gardeners who still wish to cultivate them, they should ensure regular pruning to control the size and plant them at a safe distance from the house. Given that the tree's lateral roots spread up to over 30 metres out, they can grow into ditches, plumbing pipes and septic tanks, causing damage and cracking them.

Poplar trees

Poplar trees are a favourite among homeowners due to their rapid growth, providing both shade and beauty to gardens. However, an expert has warned that these trees have powerful roots that can cause serious damage.

Melvin said: "The roots of poplar trees may invade your small garden space and can exert damaging pressure on concrete structures."

Melvin pointed out that this shade tree is best suited for large gardens with "virtually no other buildings nearby". Despite the variety in size among poplar trees, most share certain characteristics that make them easily identifiable.

For instance, poplar leaves are often heart-shaped and edged with tiny teeth, making them distinctive.

Juniper trees and shrubs

Juniper trees and shrubs, known for their colourful foliage and cones bearing green, blue, or purple berries, are found worldwide. While not inherently harmful, they can introduce "contagious plant diseases" into your garden, the expert cautioned.

Melvin said: "It is a known alternate host of rust fungus to complete its life cycle. If you have apples, crab apples, hawthorns, and other plants of the rose family, junipers should be avoided."