Buckthorn: A Comprehensive Review

Introduction

Buckthorn refers to several species of shrubs and small trees in the genus Rhamnus, primarily native to Europe, North Africa, and parts of Asia and North America. These hardy plants have gained both appreciation and notoriety for their various characteristics and impacts on ecosystems.

Physical Characteristics

Buckthorn species typically grow between 10-25 feet tall with dark green, oval-shaped leaves that remain green late into autumn. The bark is dark brown with prominent light-colored lenticels. Small greenish-yellow flowers appear in spring, developing into dark purple-black berries by late summer. The twigs often end in sharp thorns, giving the plant its common name.

Ecological Role

In its native habitats, buckthorn plays an important ecological role. The berries provide food for birds, while the dense foliage offers shelter for small animals. However, in non-native regions (particularly North America), buckthorn has become an aggressive invasive species. Its ability to leaf out early and retain leaves late gives it a competitive advantage over native plants.

Medicinal and Commercial Uses

Historically, buckthorn has been used in herbal medicine. The bark of Rhamnus frangula (glossy buckthorn) has been used as a laxative, while the berries of some species were used as dyes. Modern herbal preparations still sometimes include buckthorn components, though its use has declined due to potential side effects.

Negative Impacts

The invasive nature of buckthorn in non-native environments has caused significant ecological damage. It forms dense thickets that crowd out native vegetation, alters soil chemistry through leaf litter decomposition, and serves as a host for agricultural pests like the soybean aphid. Its berries have a laxative effect on birds, potentially affecting their health during migration.

Control and Management

Controlling buckthorn requires persistent effort. Methods include mechanical removal (pulling young plants or cutting and treating stumps), controlled burns in appropriate ecosystems, and careful use of herbicides. Restoration of native plant communities after removal is crucial to prevent re-establishment.

Interesting Varieties

While most attention focuses on invasive species like Rhamnus cathartica (common buckthorn), some ornamental varieties exist. The fine-line buckthorn (Rhamnus frangula 'Ron Williams') is a cultivated variety with a narrow, columnar growth habit popular in landscaping.

Conclusion

Buckthorn presents a complex case study in plant ecology. While valuable in its native range and historically useful to humans, its invasive tendencies in new environments have made it a significant management challenge. Understanding both its benefits and drawbacks is essential for proper environmental stewardship. Where native, it deserves protection; where invasive, it requires careful control to protect local ecosystems.