List of Invasive Plants in Gardens and What to Grow Instead

Invasive plant species can cause significant environmental harm and habitat loss in your area. Despite this, some non-native plants can offer benefits such as providing ground cover, shade, ornamental value, or attracting pollinators. For instance, English Ivy can beautify urban areas, while Butterfly Bush attracts pollinators with its vibrant flowers. This duality presents a challenge: how can the benefits of these exotic species be enjoyed without letting them become a problem? Is there such a thing as having full control over an invasive species, or is it better to consider species that can substitute them without causing havoc?

This blog discusses some of the most common invasive plants in North America, including why they are considered invasive and why people usually choose them or their gardens. Practical tips are provided on how to monitor and contain these plants to prevent them from causing environmental harm, but remember that accidental spread is always a possibility.

This blog is not intended to encourage growing invasive plants but to provide the tools to do so responsibly if that is the route chosen. Ultimately, it is up to you to make that decision, but we hope you opt for the better route and choose alternative plants instead!

Before jumping right to the list here are 4  tips that apply to growing invasive plants.

1. Grow in containers: To contain their growth and prevent their roots from spreading into natural areas.
2. Never compost: Avoid composting invasive plant material to prevent seeds or vegetative parts from surviving and potentially spreading to new areas.
3. Don't let it go to seeding: Regularly monitor invasive plants for flowering and seed production. Remove flowers and seeds promptly to prevent them from dispersing and establishing in the environment.

Now that we cover the basics of invasive plants let’s begin.

1. English Ivy

Why choose it?

Because it adds a pretty green layer that spruces up gardens and city areas, it grows thick and tough and can adapt to many environments. 

Why is it invasive?

English Ivy, originates from Europe and forms dense thickets that can smother native vegetation and climb and wrap itself around large trees causing an impact on forest edges and ground-level plant life.

Precautions

Use barriers: Implement barriers like buried edging to restrict the spread into natural areas.

Regular monitoring: Frequently check for escaped vines and vines sprouting outside the container.

Prompt removal: Immediately remove any vines that escape to prevent them from establishing outside the garden.

Alternative Plant

Virginia Creeper (Parthenocissus quinquefolia) because it provides a similar green cover and aesthetic appeal in gardens and urban areas without the invasive growth habits of English Ivy.

1. Japanese Barberry

Why choose it?

People like Japanese Barberry for its small size, colorful red leaves, and toughness. It's often used in gardens for decoration, where its dense growth makes great hedges or barriers.

Why is it invasive?

Japanese Barberry, native to Japan, forms dense patches that alter soil nutrients and displace native wildlife.

Precautions

Use sterile cultivars: Opt for sterile cultivars that do not produce seeds.

Early detection: Regularly check for and remove seedlings, especially in late spring.

Monitor for spread: Consistently monitor for any signs of spreading into nearby areas.

Remove flowers: Remove flowers before they go to seed to prevent further spread.

Alternative Plant

Dwarf Fothergilla (Fothergilla gardenii) because it has a colorful foliage and ornamental value in gardens and landscapes and is suitable for hedges or barriers without the invasiveness.

1. Purple Loosestrife 

Why choose it?

Mainly for its striking purple flowers that shoot up looking like rock candy sticks.

Why it is invasive

Purple Loosestrife displaces native wetland species, leading to habitat loss for endangered and rare species.

Precautions

Plant in containers: Use containers to limit root spread.

Avoid water sources: Keep plants away from water sources to prevent unintentional spread.

Remove flowers: Remove flowers before they seed, particularly in late summer.

Proper disposal: Dispose of plant parts by securely bagging them and placing them in the trash for landfill disposal or, where allowed and safe, burn or incinerate the plant material to ensure complete destruction of seeds and tissues, minimizing risk of spread.

Alternative Plant

Blue Flag Iris (Iris versicolor) because it has attractive purple-blue flowers and thrives in wetland conditions without displacing native species.

1. Garlic Mustard

Why choose it?

It's easy to grow and adapt to many environments, looks nice with its early spring foliage and white flowers and some even use it in cooking because its leaves and roots are edible. 

Why is it invasive?

Garlic Mustard rapidly spreads through wooded areas, disrupting native plant life and local ecosystems.

Precautions

Plant in containers: Use containers to limit root spread.

Early detection: Detect and remove plants early in the growing season.

Manual removal: Pull out plants by the roots to prevent regrowth.

Encourage native vegetation: Plant native alternatives to restore local ecosystems.

Monitor annually: Conduct annual checks to ensure garlic mustard does not reestablish.

Avoid seeding: Actively monitor the plants for flowering and seed production, and promptly remove any flowering stems before they have a chance to disperse seeds.

Alternative Plant

Woodland Phlox (Phlox divaricata) because it blooms in early spring, attracts pollinators and doesn't overwhelm the ecosystem of native wildlife.

1. Japanese Honeysuckle 

Why choose it?

It’s known for its fragrant flowers, rapid growth, and ability to attract pollinators.

Why is it invasive?

Japanese Honeysuckle forms thickets that outcompete native trees and shrubs in growth and density.

Precautions

Use hanging baskets or trellises: Grow in controlled structures to prevent ground spread.

Regular pruning: Prune regularly to control growth and prevent spreading.

Monitor frequently: Check for and remove any escaped vines.

Use native alternatives: Consider native honeysuckle species that do not pose invasive risks.

Alternative Plant

Coral Honeysuckle (Lonicera sempervirens) because it attracts pollinators with its fragrant flowers and is less invasive compared to Japanese Honeysuckle.

1. Butterfly Bush

Why choose it?

It’s used to attract butterflies and other pollinators to the area because of its fragrant flowers.

Why is it invasive?

Because they have a prolific seed production and its ability to grow undisturbed in many environments threaten native plant communities.

Precautions

Plant sterile cultivars: Use non-seeding varieties.

Deadhead spent flowers: Remove flowers before seed formation in early summer.

Regular monitoring: Frequently check for and remove any new growth.

Alternative Plant

Bluebeard (Caryopteris x clandonensis) because it attracts all types of pollinators with its blue flowers without the invasive tendencies of Butterfly Bush and there is no need to worry about accidental spread.

Final Thoughts

With this knowledge, it's crucial to take responsibility when choosing to include these plants in a garden. Evaluate the potential damage they could cause to property and neighboring environments, weigh their benefits against the risks, and explore alternative options that may be more suitable than invasive species.

Happy gardening!