Weeds can be invasive when left to grow out of their native regions as they may end up competing with plants of the area they have invaded, causing a vegetation imbalance.
One distinct way to tell weeds apart is to have a higher germination rate and have deep roots. However, it is not always easy to distinguish weeds from other plants because some look like small trees.
You might be tempted to leave the foreign tree that has started forming in your garden to grow, not knowing it is an invasive plant.
On the other hand, not every weed is dangerous; some are even willingly grown for their beneficial properties.
In this article, I have outlined several weeds that look like small trees to aid you in recognizing them.
1. Japanese knotweed
Japanese knotweed is one of the most invasive weeds in your garden. Furthermore, it spreads very fast and is extremely hard to control.
Therefore, I would advise you to get rid of it as soon as possible. It is so dangerous that it appeared on the world conservation union’s list of the world’s most invasive species.
Though it is a native Japanese plant, it has recently been sighted in different parts of the USA. Since most people do not know how dangerous it can be, homeowners have a hard time selling homes with the said weed in their garden and front yard.
At first sight, you can mistake it for a shrub due to its stout height and shape. On average, it measures anything between three to eight feet.
Its zig-zag stems are reddish and appear somehow jointed. Depending on the weather, this weed sometimes produces white-coloured panicles of flowers.
2. Southern magnolia
The Sothern magnolia is not your typical weed tree. However, it is grown in many parts of the world for its fragrant flowers and aesthetic.
This weed is easily distinguishable because of its creamy white flowers with yellow hues and thick brown bark, often peeling.
The problem with this tree is that it can grow very tall if left unchecked. In addition, its extensive roots knot together in the soil when it matures, crowding out other plants’ root systems.
Also, Southern magnolia requires a lot of nutrients to flourish, meaning there wouldn’t be a lot of nutrients left for other plants, making them harmful to some extent.
3. Willow trees
A willow tree is perfect for a massive farm as it has thick leaves that offer shade and is aesthetically pleasing.
Some people in Australia plant is entirely for wood as it makes beautiful furniture and figurines. It is also planted in flooded areas to drain the excess water.
However, it is not ideal for small gardens, parks, and backyards since its roots have the potential to grow up to 40 feet long.
Besides starving out the rest of the ecosystem, the roots will destroy the foundation of buildings, walkways, drains, and roads.
You can quickly identify a willow tree by its whitish bark with black patches, slender branches, and strong roots.
4. Hybrid poplar trees
Hybrid polar trees have very distinct compound leaves that are green with a yellow border. As the plant matures, the whole leaf turns yellow, then falls off, and the cycle repeats itself.
They have weed barks which often end up collapsing. The problem is the root system is very secure, so the plant will continually regrow.
If left to grow, your whole farm will have wilted-looking plants half the time.
5. Norway maple
As you can already tell from the name, the Norway maple is a native tree from Norway. So if you are looking for an aesthetic tree, this one will work perfectly.
The problem is it is very invasive and will starve other trees of nutrients, causing them to wither away.
The Norway maple is mainly grown for its aesthetic nature as it has broad dark green leaves that turn yellow in the fall and bears beautiful green-yellow non-edible fruits.
They will often appear in hedgerows or wooded areas, so keep an eye out.
6. Trees of heaven
Do not be fooled by the name; the tree of heaven is one of the most invasive weeds native to China but has now invaded Northern America.
It quickly multiplies by sprouting side shoots from the rootstalk, which go on and become a whole other plant.
The tree of heaven is dangerous because it releases toxins into the soil, eliminating an entire ecosystem in a short time.
Also, its leaves can cause painful rashes when they come into contact with human skin making it even harder to eliminate.
In the right conditions, this weed can grow up to 5 feet tall in one season and go on to reach 60 feet. This makes it one of the tallest weeds.
You can quickly tell it apart because of its tiny white flowers and fern-like leaves. Also, it emits a very odorous smell that is hard to miss.
Ricinus is a gorgeous plant, but it is equally dangerous. It can grow as tall as 4 feet in the right conditions, but it usually only averages 32 feet.
In addition, its flowers, leaves, and seeds produce a toxic chemical called ricin which is lethal if ingested by animals and humans, making it very dangerous for farm and wild animals.
8. Black locust
The Black locust is one of the fastest-growing weeds in the legume family. It is highly invasive and reproduces by seeds then dispersed by winds. It will have colonized your garden within no time and disrupted the ecosystem.
Most of the time, you will find Black locusts in a place with well-drained soil with a PH ranging from four to eight.
Its size mimics a small tree as its average height is 3 feet. In spring, it produces clusters of white flowers with a pleasant smell.
Also, they have pinnate compound leaves. Their leaves are their most distinguishable feature but check the bark, reddish, almost black, if you are unsure.
9. White mulberry
White mulberry is an invasive weed-like tree native to China but has recently spread to other areas.
Unfortunately, it is hard to get rid of because it is resistant to most herbicides and salt and can thrive in drought conditions. Ideally, this plant prefers warm and moist loamy soil but can grow anywhere.
You can tell it apart from its leaves because they grow in alternate arrangements, taking different structures such as serrate and dentate.
Its flowers are tiny and appear green in colour when young, then blossom to white when fully grown.
If left unchecked, the White mulberry is invasive and can colonize your garden in two seasons.
In addition, it looks like a small tree when matured, making it easy to mistake it for a beneficial tree.
10. Creeping thistle
The creeping thistle is relatively easy to spot, thanks to its distinct features. So naturally, it is a short weed of 2-5 feet.
It has purple flowers that look like nutcrackers with flowers at the top. Although it is a significant food source for farm birds, it can be invasive in your garden if left to grow.
It is not easy to differentiate weeds from other plants because some look like small trees. Japanese knotweed, southern magnolia, willow trees, hybrid polar trees, Norway tree Marple, trees of heaven, Ricinus, black locust, creeping thistle, and white mulberry are some of the weeds that look like trees.
However, not every weed is harmful; some are willingly grown for their beneficial properties.
Carla is a student pursuing a B.S in Agricultural Systems Technology. With a passion for landscaping for over 4 years, Carla loves plants. She has previously contributed to several other sites in the space before joining InsightWeeds.