Dealing With Invasive Plants, Part 1
- nvilu7
- Jun 30
- 6 min read
Updated: 11 hours ago
Why “It’s Not That Bad” Is How Plant Problems Become Regional Disasters
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How to Identify and Stop Invasive Plants Before They Take Over Your Yard
Some invasive plants arrive like burglars.
Others show up looking harmless.
That’s the dangerous kind.
Most homeowners don’t panic when a plant spreads a little too enthusiastically. They tolerate it for years because it “doesn’t seem that bad.” Then one day they realize the plant has:
swallowed half the garden,
crowded out established plants,
invaded the lawn,
cracked hardscaping,
or started climbing the fence, siding, or trees.
At that point, removal becomes expensive, exhausting, and sometimes nearly impossible.
I live in Portland, OR, which is basically heaven on earth for plants — including the ones you absolutely do not want. Some weeds in my yard stay green all winter long while my actual garden plants are dormant and trying to survive.
Frankly, it’s rude.
Invasive plants thrive because most people ignore them early, when they’re easiest to eliminate.
What Is an Invasive Plant?
In my world, an invasive plant is any plant aggressively growing where I don’t want it.
The United States Department of Agriculture has a more official definition. According to the USDA, invasive plants are non-native plants whose introduction causes environmental harm, economic damage, or risks to human health.
Sadly, “causing extreme annoyance to Nannette” did not make the list.
Why Invasive Plants Create Serious Problems
Invasive plants spread aggressively because they reproduce quickly and adapt well to most environments.
That creates problems homeowners don’t always connect back to plants:
clogged drainage systems,
damaged retaining walls,
cracked masonry,
declining biodiversity,
increased wildfire risk in some regions,
and expensive ongoing maintenance.
Some invasive plants also host insects and pathogens that damage crops, livestock, pets, and humans.
And climate change is making the problem worse by shifting growing conditions faster than native ecosystems can adapt.
Kudzu: The Vine That Ate the South
If you think these invasive plant warnings sound dramatic, let me introduce you to Kudzu.
Kudzu was introduced to the United States at the 1876 Philadelphia Centennial Exposition as an ornamental shade plant.
At the time, that sounded like a fantastic idea.
Remember:
no air conditioning,
no electric fans,
brutal Southern summers.
Fast-growing shade sounded downright civilized.
The problem is that Kudzu spreads like it’s trying to win a contest.
It can grow:
up to a foot per day,
through underground rhizomes,
through seeds,
and through sprawling vine growth.
Its roots can grow several feet deep and become almost absurdly thick.
When introduced in the U.S., Kudzu was primarily grown on trellises, which limited its ability to spread through underground rhizomes. But by the early 1900s, Kudzu was being promoted in the South as a backup livestock forage crop and increasingly planted directly in the ground — where it began to spread aggressively.
Ironically, livestock generally dislike eating Kudzu unless little else is available, making its widespread promotion as a forage crop even more misguided in hindsight.
Then the federal government accidentally supercharged the problem.
During the Dust Bowl era, the government distributed millions of Kudzu seedlings and even paid farmers to grow it for erosion control and livestock forage.
Which, in hindsight, was not ideal.
By the late 1940s, especially in the South, farmers had become increasingly concerned about Kudzu spreading far beyond the fields where it had been planted. Kudzu began covering everything — literally — choking out hundreds of thousands of acres of the South’s species-rich native forests that had taken millions of years to evolve.
After nearly a decade of pushback from Southern states, the federal government slowly began pulling back its support for Kudzu.
In 1953, the United States Department of Agriculture removed Kudzu from the list of cover plants permitted under the Agricultural Conservation Program. By 1970, the USDA had reclassified Kudzu as a common weed.
Finally, in 1997 — after more than half a century of mounting evidence of its destructive impact — Kudzu was officially listed as a noxious weed under the Federal Noxious Weed Act.
Kudzu’s economic cost to Southern states is difficult to comprehend. Shortly after Kudzu was officially classified as a noxious weed in 1997, a U.S. government publication estimated that it caused more than $100 million in damage annually — roughly $188 million in today’s dollars.
Kudzu remains a significant problem today, especially in the Southeast, where it blankets an estimated 7.4 million acres.
Why the Kudzu Story Matters Today
Kudzu is an extreme example.
But it illustrates something important:
Plants that seem useful, attractive, or manageable at first can become ecological nightmares when conditions are right.
Today, invasive plants spread even faster because:
global commerce moves plants worldwide,
online plant sales bypass regional growing knowledge,
warmer winters help aggressive plants survive,
and homeowners unknowingly share invasive plants with neighbors.
Once an aggressive plant gets established, gardening starts to feel less like creating something and more like permanently holding the line.
That’s why every gardener should learn what invasive plants are common in their region.
Invasive Plants vs. Noxious Weeds
Most states maintain official invasive plant or noxious weed lists through their agriculture departments.
The terms overlap, but they are not identical.
Noxious weeds:
Legally designated harmful plants targeted for containment or eradication.
Invasive plants:
Aggressive spreaders that damage ecosystems or crowd out desirable plants.
In practical homeowner terms?
If a plant aggressively spreads where you don’t want it, pay attention.
Oregon’s Invasive Plant Categories
Here in Oregon, invasive plants are divided into categories based on how aggressively the state wants to control them.
The most concerning categories receive funding for:
education,
containment,
and eradication efforts.
Why?
Because it’s dramatically cheaper to stop an invasive plant early than to control it after it spreads statewide.
Which brings us to one of my personal cautionary tales.
My Battle With Gooseneck Loosestrife
I originally planted gooseneck loosestrife because I loved the flowers.
And honestly?
I still do.
It’s beautiful in arrangements and incredibly striking in bloom.
Unfortunately, in regions that do not experience hard winter freezes, it behaves like it’s trying to annex neighboring countries.
By the second growing season in my old Pittsburgh garden, it had already started wiping out nearby perennials.
The beebalm disappeared first.
Then the daylilies started losing ground.
After two years of digging, dividing, replanting, and installing 14” hammer-in barriers, I finally managed to contain it.
So naturally, when I planted it again in Portland, I put it in two big raised beds.
Because apparently I enjoy living dangerously.
A plant doesn’t have to appear on your state’s official invasive list to become a problem in your yard.
Dealing with Invasive Plants in Your Yard—Build Your Own Invasive Plant Watch List
Your state’s invasive plant database is a great starting point — but don’t stop there.
Also:
review neighboring states’ invasive plant lists,
ask local gardeners what spreads aggressively,
talk to Master Gardeners,
visit native plant society websites,
and pay attention to plants repeatedly described as “vigorous,” “aggressive,” or “fast-spreading.” Those words are often polite nursery-industry code for “Good luck.”
Start your personal invasive plant war with these weapons in your arsenal:
Helpful Resources for Identifying Invasive Plants
Helpful resources include:
local native plant societies
local Audubon chapters
university extension offices
Plant identification apps can also help you identify unknown volunteers before they become established.
Helpful Tools for Controlling Invasive Plants
These are the tools I reach for constantly when dealing with aggressive plants and garden thugs.
FELCO pruners — for cutting back aggressive stems and vines.
Hori hori garden knife — excellent for digging out rhizomes and stubborn roots. Assassin-level heavy-duty.
Vego Garden Raised Beds — useful for containing aggressive spreaders you still insist on growing despite knowing better.
Garden Weeding Gloves from Foxgloves — protects hands when pulling tough weeds.
Root Barrier Panels — helpful for containing rhizome spreaders when planted in the ground.
Next Up in Part 2: Identifying, Removing, and Preventing Invasive Plants
Knowing what you’re dealing with is the first step.
Next comes the satisfying part:
identifying plant invaders,
removing them effectively,
and preventing them from coming back.
I’ll cover that in Part 2.
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