Introduction to 8 Plants Not to Grow in Your Garden
Home gardens provide bountiful produce and beautiful landscaping, but some common plant choices should be avoided.
Identifying plants not suited for cultivation can prevent costly invasive species issues and protect human health.
This article explores 8 plants that are best left out of gardens due to their toxicity, competitive growth habits, or legal status as noxious weeds.
Poison Ivy
Poison ivy tops the list of plants not to grow in gardens due to its highly toxic sap, known as urushiol. This oil causes an itching rash called urushiol-induced contact dermatitis in most people within 12–48 hours of exposure.
Identifying Poison Ivy
Poison ivy can be found in three forms across North America:
| Form | Leaf Configuration |
| Upright/shrubby | Groups of three oval leaves |
| Trailing vines | Groups of three oval leaves |
| Leafless poison ivy | Greenish-white berries in fall/winter |
Spread and Prevention
Poison ivy is adept at spreading, with birds and other animals inadvertently transporting its windborne seeds.
It’s best removed by carefully bagging all plant parts and disposing of them where wildlife cannot contact them. Even dead poison ivy leaves can cause a reaction in sensitive individuals.
Common Burdock
While its edible roots were once harvested, common burdock has become a pest due to its prolific seed dispersal via burr-like burs that readily attach themselves to pants and fur.
These “ticks” of the plant world can remain viable after traveling long distances on animals, clothing, or vehicles. Once established, burdocks form large, competitive taproots that are difficult to fully remove from gardens.
Bamboo
While some clumping bamboo varieties can make attractive privacy screens, other running bamboo species should be avoided.
Runs of invasive bamboo can spread dozens of feet each year through an extensive underground network of rhizomes.
This facilitates its escape from containment and crowding out of desired plantings. Only non-invasive bamboo types are recommended for landscaping.
Poison Hemlock
Poison hemlock, a common roadside plant resembling edible carrots or parsley, is extremely toxic.
All plant parts contain compounds, including coniine, that can induce respiratory failure if sufficient quantities are ingested.
This is especially dangerous for young children and grazing animals, who may mistake it for a safe plant.
Poison hemlock should never be cultivated and must be disposed of carefully away from access.
Japanese Knotweed
Originating from East Asia, Japanese knotweed has become a problematic invasive weed across much of North America and Europe, able to colonize virtually any terrestrial habitat.
It forms dense thickets through an extensive rhizome system that can extend over 7 meters deep. This “mega-mutant” of a plant shoots up tall green stalks with heart-shaped leaves and tiny white flowers in late summer.
Impenetrable thickets of Japanese knotweed displace native plants and damage infrastructure like asphalt, concrete, and building foundations as its roots pry them apart.
Where established, complete removal can require multi-year efforts using herbicides or manual removal of all plant parts.
Multiflora Rose
Once popularly planted as “living fences” that eventually form impenetrable thickets, choking out all other vegetation, multiflora rose has become one of North America’s worst invasive species.
Its thorny stems spread over 10 feet each season, forming dense stands that exclude native plants and form monocultures unable to be reclaimed naturally.
After years of widespread colonization, multiflora has now infested abandoned lots, pastures, and untended areas across much of the eastern and midwestern US. Mechanical or chemical control methods are required for removal.
Crown Vetch
An erosion-controlling groundcover promoted for slopes and banks, crown vetch does its job too well by forming dense mats that smother other vegetation.
Given opportunity, it spreads rapidly by seed and creeping rootstalks. While useful in areas where it cannot escape, crown vetch can prove challenging to eradicate once established in gardens or other plantings.
Its invasive tendencies usually arise from plantings improperly sited or maintained where dispersal is possible.
Tree of Heaven
Originating from East Asia like Japanese knotweed, the Tree of Heaven is another elite invader species capable of outcompeting natives across varied landscapes.
Its saplings grow rapidly to towering heights, forming allelopathic chemicals in their roots that inhibit other plants. Mature trees spread copiously by wind-borne seed and root sprouts, especially along disturbances.
Once tree of heaven gains a foothold, it requires intensive efforts to remove individuals and regenerating stumps before seeds can disperse another generation.
Preventing its introduction near gardens is the wisest approach.
Conclusion
While many popular garden plants present little risk, the species highlighted here can cause costly damage, threaten surrounding habitats, or endanger public health.
By avoiding the purposeful cultivation of invasive or toxic plants, gardeners worldwide can contribute to environmental protection and community wellness.
Remaining watchful also prevents accidental spread through removed plant parts; simple identification helps proactively manage potential problems before they become established.