Aggressive vs Invasive: Why the Distinction Matters

Language matters. We often use words interchangeably that seem similar but carry important distinctions. One common mix-up I hear, even among experienced gardeners and clients, is between the terms “aggressive” and “invasive.”

When we talk about plant behavior, aggressive refers to a plant that grows quickly and vigorously or reseeds highly, often outcompeting its neighbors for sunlight, moisture, and nutrients—sometimes to the point of crowding them out. Aggressive plants can appear in both cultivated gardens and wild landscapes. But calling a plant aggressive doesn’t mean it’s a bad plant. It just means you need to be mindful of its neighbors and how much elbow room it has.

Invasive, on the other hand, is a more serious label. An invasive plant is aggressive and exotic (non-native to the region) and has been documented to spread beyond garden borders into local ecosystems. Once there, it has demonstrated the ability to outcompete native plants, reducing biodiversity and disrupting ecosystem functions. The key distinction: aggressive describes behavior, while invasive also refers to negative ecological impact.

How Do Invasive Plants Harm Ecosystems?

In addition to an aggressive growth habit, invasive plants have a few key advantages that allow them to take over ecosystems:

• Lack of Predators: Native plants evolved alongside local insects, caterpillars, and animals that feed on them—keeping their growth in check. Exotic invasives often escape this natural regulation, giving them a growth advantage. The flip side? They offer little to no food value for wildlife. As they replace native plants, they effectively starve the local food web.

• Out-of-Sync Growth Calendars: Many invasives leaf out earlier in the spring or hold leaves longer in the fall—sometimes staying evergreen—giving them more time to hog sunlight and suppress neighboring natives.

But What If I Keep Them in Check?

Some gardeners wonder: If I monitor the spread on my property, isn’t it okay to keep invasive plants? Unfortunately, it’s not that simple. The issue isn’t just what happens in your garden—it’s whether your garden becomes a source of spread. Birds eat berries and spread seeds far beyond your fenceline. Wind and water can carry seeds downstream or across neighborhoods.

So the question becomes: Do we only bear responsibility for our own yards? Or for the ecosystems we’re connected to?

Examples: Aggressive Natives vs. Invasive Exotics

Here’s a look at some plants you might encounter:

• Aggressive Native Plants: These are beneficial to wildlife but can be garden bullies if not sited carefully:

  • Bee Balm (Red & Wild)

  • Mountain Mints (Narrowleaf Mountain Mint is better behaved)

  • River Oats

  • Big Bluestem

  • Pink Evening Primrose

  • Golden Ragwort

  • Canada Goldenrod

  • Trumpet Vine

  • Common Milkweed

• Invasive Exotic Plants: These are ranked by the NC Native Plant Society for their threat level. (* indicates plants still sold at local nurseries.) See here for a more complete list.

  • Rank 1 – Severe Threat - unfrotuntely, these are all seen in local yards as well as along local greenways/parks

    • English Ivy

    • Privet (Chinese, Japanese, Glossy)

    • Bradford Pear Tree

    • Tree of Heaven

    • Japanese Stilt Grass

    • Chinese Wisteria

    • Miscanthus* (especially in the mountains)

    • Lesser Celandine / Buttercups

    • Japanese Honeysuckle

  • Rank 2 – Significant Threat: Exotic plant species that display some invasive characteristics, but do not appear to present as great a threat to native communities in NC as the species listed in Rank 1.

    • Leatherleaf Mahonia*

    • Nandina (Heavenly Bamboo)*

    • Vinca / Periwinkle*

    • Burning Bush*

    • Wintercreeper*

    • Butterfly Bush*

So What Can We Do?

When planning a garden or assessing existing beds, give aggressive plants the space and competition they need to be kept in check.  Or save them for use in natural areas where you can take advantage of their ability to cover ground fast and don’t mind if they take over.  As for invasives, the starting point is to avoid buying any new invasives. On this front, you need to be an educated consumer as the nursery industry is happy to sell many invasives. The same characteristics that make them invasive (easy to propagate, grow fast, tough to kill) make them profitable for nurseries and an easy sell to customers just looking for something is easy to grow. Chances are, we all have a few (myself included; we still have some nandinas my wife loves). I’m not suggesting you need to yank everything out tomorrow. But alongside the joy of planting new flowers, shrubs, and trees, take time to identify the invasive species in your yard, be honest with yourself that they are or could become problematic, and put a plan in place to phase them out.

You might be surprised what comes back when the invasive plants  are gone. Sometimes, native plants that were quietly hanging on will rebound once they get a little breathing room.  In my own yard, crossvine, a spring blooming vine that feeds ruby throated hummingbirds, took off once I removed the vinca and Japanese honeysuckle.