You may be introducing invasive plants into your garden unintentionally or intentionally. You may be doing it unintentionally because you were never alerted that a particular plant species is invasive. You may be doing it intentionally because plants you like may be invasive. The latter includes herbs.
There are two methods in which herbs become invasive –- they freely scatter their seeds that then sprout on their own, while others create rhizomes or root-like stems that ramble just under the surface of the soil developing new plants as they go. Whatever the method, these species of plants can overrun your garden and crowd out other species of plants.
Don’t fret. You don’t have to eradicate the herbs you want to include in your garden because they are invasive. However, you will have to find ways to control them.
First let us learn some general information about invasive plants.
What Makes Them Invasive?
A plant that thrives and aggressively spread beyond its native reach is categorized as an invasive plant. Some spread slowly into small areas and don’t become a problem. Others, however, are naturally aggressive in their native environment, spread outside their native range and keep spreading threatening to choke out other plants that animals and insects depend on.
There are five traits of invasive plants that help you identify them. They include:
- Producing a large number of offspring each season.
- The ability to tolerate an assortment of soil types and climates.
- Spreading easily.
- Rapidly and easily overtaking slower growing plants.
- Spreading aggressively when not constrained.
Methods Of Control
You don’t necessarily have to eliminate these plants from your garden. Instead, you can constrain them. This is achieving in a number of ways:
- Plant in a pot and leave it above ground or sink the pot into a hole in the garden with its rim about an inch or two above the soil line. A 6-inch pot with draining holes would be ideal. Be sure to dig up and repot the plant every two to three years so it won’t become root bound.
- Install plastic edging at least 10-inches underground to stop the plant’s roots from spreading.
- Pinch the plant back regularly to prevent it from producing flowers and throwing seed all over the garden.
- Deadhead the spent flower as soon as it wilts to prevent reseeding.
If despite your attempts to manage it, the invasive plant spreads anyway, dig up the entire root system of the undesired sprouts.
Invasive Herbs And Plants
Some of the most common invasive herbs include:
- Bee balm
- German Chamomile
- All mints
- St. John’s wort
Other invasive plants include:
- Oriental, American and Nightshade bittersweet
- American and Chinese Wisteria
- English Ivy
- Sweet Autumn Clematis
- Burning Bush
- Butterfly Bush
- Common Privet
- Norway Maple Trees
- Japanese Knotweed
- Purple Loosestrife
- Japanese Honeysuckle