Key Facts
- Deciduous shrub or small multi-stemmed tree
- Introduced from Europe and parts of Asia and now invasive in parts of North America
- Forms dense thickets that shade and outcompete native plants
- Produces clusters of small yellowish flowers in spring
- Fruits are small black berries eaten and dispersed by birds
- Tolerant of a wide range of soils and light levels
- Control is commonly by cutting, pulling seedlings, and targeted herbicide on stumps
Buckthorn Rhamnus cathartica is a deciduous shrub or small multi stemmed tree that often forms dense invasive thickets in areas where it is nonnative. It produces small yellowish flowers in spring and black berries that birds disperse widely.
Identification
Leaves and stems are typically arranged on multiple stems that form a clump. Mature plants commonly reach 15 to 25 ft tall and often spread 10 to 20 ft by suckering and seedling recruitment. Small yellowish flowers appear in spring around May and June and develop into black berry clusters later in the season.
Where it grows and common uses
The species tolerates full sun to deep shade and a wide range of soils including clay loam and sand. That adaptability makes it able to invade woodlands, field edges and disturbed sites where it can shade out native plants. Because it is nonnative and invasive in many regions it is generally not recommended for planting where local regulations or conservation priorities aim to limit invasive species.
Planting and establishment
Natural spread is driven by birds that eat the berries and by root suckers that form new stems. Seed rain from birds and vegetative sprouts lead to new plants rather than predictable crown spread from a single trunk. Hardiness is commonly reported around USDA zones 3 to 7 but local conditions vary.
Water and light
Buckthorn tolerates a wide moisture range and will grow in wet or compacted soils as well as well drained sites. Plants persist in heavy shade as well as open sun. Shadier conditions can reduce flowering and berry set but do not prevent persistence.
After flowering and seasonal care
Flowers appear in spring and fruit ripen later in the season. Removing fruiting stems or cutting back plants before heavy berry set reduces seed available to birds. Seedlings are easiest to remove when small by pulling or digging while roots are short.
Controlling spread and removal
Common control methods include cutting stems, pulling seedlings, and applying a targeted herbicide to fresh stumps where permitted. Repeated follow up is often required because root sprouts and seedling recruitment can recreate dense stands. Because seeds are spread by birds and seedbank persistence varies consider disposing of cut branches and fruit away from wild or natural areas.
Safety and toxicity
Berries have a history of laxative use and can cause gastrointestinal upset in people and pets if eaten. Treat exposures seriously and consult poison control or a veterinarian for guidance on human or animal ingestion.
Frequently asked questions
- How fast does Buckthorn grow?
- Mature size is commonly 15 to 25 ft and spread can be rapid at a site because of seed from birds and root suckering. Rate varies with site quality and climate.
- Is Buckthorn invasive?
- Yes in many parts of North America where it was introduced from Europe and parts of Asia. It forms dense thickets that shade and outcompete native plants.
- Are the berries poisonous?
- Berries can cause laxative effects and gastrointestinal upset in humans and animals. Seek professional guidance for exposures.
- How do I remove Buckthorn?
- Pull small seedlings, cut larger stems and treat stumps with a targeted herbicide where allowed. Multiple treatments and monitoring are usually needed.
- When does Buckthorn flower?
- Small yellowish flowers appear in spring commonly around May and June in the Northern Hemisphere.
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