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Common buckthorn leaves and berries

How To Control Invasive Buckthorn

Excerpted from: Buckthorn management

Buckthorn management is a multi-year commitment as the seeds in the soil can germinate for many years.

Your plan will depend on how much time you have and how dense your buckthorn is. For just a few small plants your plan may be as simple as a weekend of pulling buckthorn seedlings and regularly checking to see if new plants have taken root each year. For larger buckthorn infestations the first part of your plan should be to remove the entire berry producing buckthorn on your property.

  Buckthorn Description

Common Buckthorn
Rhamnus cathartica
Lifespan: 10 years
Height: 16 to 25 feet
Width: 10 to 15 feet
Leaves: Elliptic to oval, mostly sub-opposite, hairless, dark green leaves
Flowers: Yellow-green, insignificant
Blooms: April to June
Fruit: Round, fleshy, berry-like, black drupe
Reproduction:    By seed, although it can also regenerate from root and stump sprouts

Common buckthorn is a tall shrub to small tree that can reach up to 25 feet with one to multiple stems. Leaves are oval, 1 – 2½ inches long, are finely toothed along the edges, and have 2 – 3 pairs of prominent veins curving toward the leaf tip. The leaves can be directly opposite each other, nearly opposite, or alternate.

Common buckthorn bark is gray to brown with prominent, dark, eye-shaped pores called lenticels (raised pores in the stem of a woody plant that allows gas exchange), becoming roughened with age. Cutting the bark exposes yellow sapwood and orange heartwood.

Twigs often end in sharp spines that are 1/5 – 9/10 inches long. Common buckthorn is most frequently dioecious, meaning that male and female flowers usually occur on different plants. However, male and female flowers are very similar in appearance. They emerge in the spring in clusters of 2 – 6 and have four pale green petal-like sepals. Each flower is ¼-inch in diameter. Inflorescences are fragrant.

Abundant clusters of round, pea-sized fruit appear green on female plants in July to August, ripening to black in early fall. Fruits contain 3-4 seeds and can remain on plants into winter.

  Ecological Threats

Threatens the future of forests, wetlands, prairies, and other natural habitats.
Out-competes native plants for nutrients, light, and moisture.
Allelopathic in that it produces chemical compounds that inhibit the growth of other vegetation.
Contributes to erosion by out-competing plants on the forest floor that help hold soil in place.
Serves as host to other pests, such as crown rust fungus and soybean aphid.
Lacks natural controls, such as insects or disease that would curb its growth.

  Removing Buckthorn

Common buckthorn leaves and ripe berries

  Plants with stems less than two inches

If less than 3/8 inch in diameter, plants can be removed by hand. Small seedlings can be pulled and will not re-sprout. If greater than 3/8 inch, use a hand tool that pulls the shrub out, such as an Uprooter or Root Talon. Removing by hand is easier if the soil is moist.

  Plants with stems more than two inches

Buckthorn plants that are 2 inches in diameter or larger are best controlled by cutting the stem at the soil surface and then covering or treating the stump to prevent re-sprouting. Cutting can be effectively done with hand tools (for a few plants), chain saws or brush cutters.

  Treating Buckthorn

  Herbicide Treatment

Buckthorn Blaster.
Buckthorn Blaster

Always follow label instructions for herbicides.

Chemical control options for cut stumps include treating the stump immediately after cutting (within 2 hours) with a herbicide containing triclopyr (Garlon 3A/Vastlan, Garlon 4, or other brush killers with triclopyr) or glyphosate to prevent re-sprouting.

Herbicides can be applied to cut stumps with a paint-brush, wick applicator such as a dauber or Buckthorn Blaster, or a low volume sprayer. When using water-soluble herbicide products like most brush killers (Garlon 3A/Vastlan, or any of the glyphosate products) treat only the cut surface.

When using oil-based products (like Garlon 4 or Pathfinder II) treat the cut surface and the remaining bark to the ground line.

  Non-chemical Treatment

Buckthorn Baggie.
Buckthorn Baggie

Cut the stem of the plant a few inches above the soil. Cutting can be effectively done with hand tools (for a few plants), chain saws or brush cutters. Cover the cut stump with a tin can or black plastic (such as a Buckthorn Baggie) to prevent re-sprouting. After cutting the tree, apply the can or plastic over the cut stump and root flare.

Use nails to affix the can or a tie to affix the black plastic. Leave in place for one to two years. Check plants regularly to ensure no new growth is occurring from the cut stumps.

  Long Term Buckthorn Management

Buckthorn seeds in the soil can remain viable for up to 5 years.

Tackling your buckthorn will be an ongoing endeavor, requiring regular follow-up. Follow-up control of seedlings that emerge after initial control efforts is important on all sites. With no follow-up control, buckthorn will come back. Follow-up control options include treating the buckthorn seedlings and samplings using the pulling, cutting, and chemical methods described above.

Fire also offers a long-term management option in grassland or savanna cover-types. Burning will need to be done every two to three years.

More Gardening Tips:

 Do-It-Yourself Safe Pesticides
 How To Use Eggshells In The Garden
 Provide Spring Nesting Materials For Birds
 Best Practices For Perennial Plant Fertilization
 How To Use Rooting Hormones
 Spring Pruning Basics

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