Invasive Species

Mint, belonging to the genus Mentha, is a versatile and aromatic herb prized in culinary, medicinal, and ornamental applications. Its aromatic foliage and diverse flavors make it a valuable addition to any garden, but its unchecked growth can quickly become overwhelming. This guide will help you identify different types of mint and provide strategies for effectively managing its growth in your garden.

Identifying Mint Varieties:
Mint encompasses several species and countless cultivars, each with its unique characteristics and flavors. Here are some common types of mint and their distinguishing features:

1. Peppermint (Mentha x piperita):
   - Leaves: Dark green, lance-shaped leaves with serrated edges and a strong peppermint aroma.
   - Flavor: Intensely minty with hints of menthol.
   - Growth Habit: Upright growth habit with square stems.

2. Spearmint (Mentha spicata):
   - Leaves: Bright green, spear-shaped leaves with serrated edges and a refreshing minty fragrance.
   - Flavor: Mildly sweet and minty, often used in culinary applications.
   - Growth Habit: Spreading by rhizomes to form dense patches.

3. Chocolate Mint (Mentha x piperita 'Chocolate'):
   - Leaves: Dark green leaves with a hint of purple and a distinct chocolate aroma when crushed.
   - Flavor: Mild mint flavor with subtle chocolate undertones.
   - Growth Habit: Vigorous spreader, best contained in pots or confined areas.

4. Apple Mint (Mentha suaveolens):
   - Leaves: Oval to rounded leaves with a fuzzy texture and a fruity aroma reminiscent of apples.
   - Flavor: Sweet and slightly fruity, ideal for teas and desserts.
   - Growth Habit: Spreading by runners, may become invasive if not managed.

Managing Mint in Your Garden:
While mint's vigorous growth can be advantageous in some scenarios, it requires careful management to prevent it from overtaking your garden. Here are some strategies for controlling mint:

1. Containment: Plant mint in containers to restrict its spread. Use pots with adequate drainage to prevent waterlogging.
2. Regular Harvesting: Prune mint regularly to promote bushy growth and prevent it from becoming leggy. Harvest leaves as needed for culinary or medicinal purposes.
3. Root Barriers: Install underground barriers, such as plastic or metal edging, to prevent mint from spreading via rhizomes. Bury the barrier at least 6-8 inches deep to effectively contain the roots.
4. Selective Pruning: Remove invasive runners and trim back overgrown areas to maintain control over mint's growth. Focus on removing stems that are encroaching on other plants or spreading beyond designated areas.
5. Companion Planting: Plant mint alongside companion plants that can help suppress its growth, such as basil, chives, or onions. These plants can compete with mint for resources and limit its spread.
6. Regular Monitoring: Keep a close eye on mint patches and promptly remove any stray runners or unwanted growth. Regular maintenance is key to preventing mint from becoming invasive.

Image attribution: 
NasserHalaweh, CC BY-SA 4.0, via Wikimedia Commons
Commonists, CC BY-SA 4.0, via Wikimedia Commons
Fernando Losada Rodríguez, CC BY-SA 4.0, via Wikimedia Commons

Porcelain Berry, also known as Amur Peppervine (Ampelopsis brevipedunculata), is a fast-growing vine native to East Asia. While initially cultivated for its ornamental berries, this invasive plant has become a nuisance in many regions due to its aggressive growth and ability to outcompete native vegetation. This guide will help you identify porcelain berry and provide organic methods for effectively eradicating it from your garden.

Identification:
Identifying porcelain berry is crucial for implementing control measures. Here are key features to look for:

1. Leaves: The leaves of porcelain berry are typically heart-shaped or lobed with serrated edges. They are alternately arranged along the stem and range in color from green to variegated with shades of white, pink, or purple.
2. Vines: Porcelain berry vines are slender, woody, and can grow up to 20 feet in length. They twine around structures and other plants, often forming dense mats.
3. Berries: One of the most distinctive features of porcelain berry is its clusters of colorful berries, which change from green to shades of blue, turquoise, purple, or white as they ripen.
4. Habitat: Porcelain berry thrives in a variety of habitats, including forests, fields, roadsides, and gardens. It tolerates a wide range of soil types and light conditions.

Organic Eradication Methods:
Controlling porcelain berry organically requires a combination of manual removal, cultural practices, and persistence. Here are some effective methods:

1. Manual Removal: Hand-pulling or cutting down porcelain berry vines is effective for small infestations. Be sure to remove as much of the root system as possible to prevent regrowth. Do not throw the pulled plants into the compost bin. Rather, bag the plants and dispose of them at home.
2. Smothering: Covering the ground with a thick layer of mulch, such as cardboard, newspaper, or wood chips, can smother porcelain berry and prevent it from regrowing. Be sure to monitor the area regularly and replenish the mulch as needed to maintain coverage.
3. Repeated Monitoring: Porcelain berry can be persistent, so regular monitoring and follow-up are essential. Check the area where the plant was removed for any signs of regrowth, and promptly intervene to prevent it from spreading.
4. Avoid Disturbance: Minimize soil disturbance in areas where porcelain berry has been eradicated to prevent dormant seeds from germinating. Mulch and plant cover crops to stabilize the soil and create unfavorable conditions for weed growth.

Image attribution:
Olivier Vanpé, CC BY-SA 3.0, via Wikimedia Commons
Pancrat, CC BY-SA 3.0, via Wikimedia Commons
Pancrat, CC BY-SA 3.0, via Wikimedia Commons

Creeping Charlie, also known as Ground Ivy (Glechoma hederacea), is a persistent and invasive weed that can quickly take over your garden if left unchecked. Recognizable by its scalloped leaves and creeping stems, this resilient plant can be challenging to control. However, with proper identification and organic gardening methods, you can effectively manage Creeping Charlie. Let's explore how to identify and eradicate this invasive plant organically.

Identification:
Identifying Creeping Charlie is essential for effective control. Here are some key characteristics to look out for:

1. Leaves: Creeping Charlie has rounded, scalloped leaves with a crinkled texture. The leaves are typically dark green, with a glossy appearance and a slightly aromatic or musky scent when crushed.
2. Stems: The creeping stems of Creeping Charlie root at nodes as they spread along the ground. The stems are square-shaped and can form dense mats, especially in shady areas.
3. Flowers: In spring, Creeping Charlie produces small, purplish-blue flowers that resemble miniature orchids. These flowers appear in clusters and attract pollinators.
4. Habitat: Creeping Charlie thrives in moist, shaded areas, such as lawns, garden beds, and along woodland edges. It can tolerate a wide range of soil types and light conditions.

Organic Eradication Methods:
Controlling Creeping Charlie organically requires a combination of manual removal, cultural practices, and persistence. Here are some effective methods:

1. Hand Pulling: Regularly inspect your garden for Creeping Charlie and manually pull up the plants, including the roots. This method is most effective when the soil is moist, making it easier to remove the entire plant. Do not throw the pulled plants into the compost bin. Rather, bag the plants and dispose of them at home.
2. Smothering: Covering infested areas with mulch or dense ground covers can smother Creeping Charlie and prevent it from regrowing. Apply a thick layer of organic mulch, such as wood chips or straw, to block sunlight and inhibit weed growth.
3. Improving Soil Health: Creeping Charlie often thrives in compacted or nutrient-poor soil. Improve soil health by aerating compacted areas, amending soil with compost or organic matter, and maintaining proper drainage to create unfavorable conditions for weed growth.
4. Repeated Monitoring: Creeping Charlie can be persistent, so regular monitoring and follow-up are essential. Check the area where the weed was removed for any signs of regrowth, and promptly intervene to prevent it from spreading.

Image attribution:
Melissa McMasters from Memphis, TN, United States, CC BY 2.0, via Wikimedia Commons
Mike Dickison, CC BY 4.0, via Wikimedia Commons

Bermuda grass, scientifically known as Cynodon dactylon, is a resilient and fast-spreading warm-season grass that can quickly invade your garden. While prized for its drought tolerance and durability, Bermuda grass can become a nuisance when it encroaches upon desired plants and disrupts garden aesthetics. This guide aims to help you identify Bermuda grass and provides organic methods for effectively managing and eradicating it from your garden without resorting to synthetic chemicals.

Identification:
Identifying Bermuda grass is crucial for successful control efforts. Here are some key characteristics to look for:

1. Appearance: Bermuda grass forms dense mats of fine-textured, wiry stems that can grow close to the ground or upright, depending on mowing height. The leaves are narrow, pointed, and arranged alternately along the stems.
2. Color: Bermuda grass exhibits various shades of green, ranging from light to dark, depending on factors such as soil fertility, water availability, and sunlight exposure.
3. Root System: Bermuda grass has a robust and extensive root system, consisting of both surface runners (stolons) and underground rhizomes, which allow it to spread rapidly and establish new plants.
4. Growth Habit: Bermuda grass thrives in full sun but can tolerate some shade. It is highly adaptable and can grow in a wide range of soil types, from sandy to clayey, as long as drainage is adequate.

Organic Eradication Methods:
Controlling Bermuda grass organically requires a multifaceted approach that targets both above-ground growth and underground rhizomes. Here are some effective methods:

1. Hand Digging: For small patches of Bermuda grass, manually dig up the plants, making sure to remove as much of the root system as possible. This method is labor-intensive but effective for targeted removal. Do not throw the pulled plants into the compost bin. Rather, bag the plants and dispose of them at home.
2. Solarization: Cover infested areas with clear plastic sheeting during the hottest months of the year to solarize the soil and kill Bermuda grass and its seeds. Leave the plastic in place for 4 to 6 weeks to ensure thorough eradication.
3. Smothering: Suppress Bermuda grass by covering infested areas with mulch or heavy-duty landscape fabric. Apply a thick layer of organic mulch, such as wood chips or straw, to block sunlight and inhibit weed growth. Landscape fabric can be used in areas where no desirable plants are present.
4. Vinegar Solution: Spray Bermuda grass with a solution of horticultural vinegar (20% acetic acid) mixed with water and a small amount of liquid dish soap. This organic herbicide can help kill Bermuda grass without harming surrounding plants when applied directly to the foliage on a sunny day.
5. Persistence: Bermuda grass can be tenacious, so be prepared to implement control measures consistently and monitor the area for regrowth. Regular maintenance and vigilance are key to preventing Bermuda grass from reestablishing itself in your garden.

Image attribution:
Forest & Kim Starr, CC BY 3.0, via Wikimedia Commons
Javier martin, Public domain, via Wikimedia Commons
Betty Marose, via UMD Extension

Tree of Heaven - Ailanthus altissima

In late Spring, Tree of Heaven seedlings may appear in your garden. This is a very challenging invasive plant in North America to control and has risen in priority for control because it is the preferred host of the spotted lantern fly. An adult tree can grow to over 80’ tall.

Manual Removal: May and early June are the best times to remove this plant before it gets established and non-organic spray is needed. DO NOT just pull or cut this without intention. If you don’t remove the whole plant including the hooked root stem, IT WILL SPREAD FASTER UNDERGROUND and you will be battling this plant all summer.

To remove: Remove some soil around the base of the stem to see which way it is angling under ground. Dig down about 3” and UNDER the direction that the stem is angling. The goal is to take out the entire plant including the “hook” root, a sucker.

Disposal: Bag it in the trash and throw it away at home please. Do not compost it. It roots easily and will spread like crazy. 

Seedlings/young trees- look like in the pictures below and can grow in any type of soil. A good way to identify them is by crushing a leaf- it smells like burnt rubber or peanut butter.