Thorny weeds not only pose danger to people and animals, but when they also have yellow berries, they can become a bigger concern, because they are often also poisonous.
In this article, we’ll look at these distinct weeds to help you identify them and show you ways to control them so you can protect your loved ones and outdoor spaces.
1. Golden Dewdrop (Duranta erecta)
- Family: Verbenaceae
- Annual or Perennial: Perennial or annual in colder climates
Golden Dewdrop (Duranta erecta) is an evergreen shrub that can grow 4-6m in height. It produces yellowish-green ovate leaves that are about 2.5 -7.6 cm long.
Mature plants have axillary thorns, which may be absent in younger plants. It produces clusters of yellow berries from late summer to fall, and each berry is about 7-10 mm in diameter.
The berries are poisonous, and fatalities in children and pets have been reported. However, they are not harmful to birds.
It is native to:
- North America (Florida and Texas)
- Brazil
- West Indies
Removal Methods
- Pulling: Hand pulling works best for smaller plants. Ensure all the roots are removed.
- Herbicides: Apply a selective herbicide like metsulfuron-methyl or 2,4-D + picloram for spot spraying and triclopyr +picloram for treating cut stumps to prevent regrowth.
2. Buffalo Bur (Solanum rostratum)
- Family: Solanaceae
- Annual or Perennial: Annual
Buffalo Bur (Solanum rostratum) is a tall annual plant that can grow to 1m in height. It produces leaves (5-12cm )that are lobed and alternatively arranged along the thorny stems.
Apart from its showy yellow flowers, the weed also produces fleshy yellow prickly berries.
The thorny stems and leaves not only make the plant dangerous for grazing livestock, but the immature berries are also poisonous. However, as they mature, the berries become less of a danger.
It is native to:
- Northern America
- Northern and Central Mexico
Removal Methods
- Cultural: Planting a competitive vegetative cover can edge out the weed.
- Pulling: Pulling or hand digging can help remove solitary plants (wear heavy gloves)
- Herbicides: Apply 2,4-D when the seedlings are immature. 2,4-D and Banvel (containing Dicamba as the active ingredient) provide the best control against Buffalo Bur.
3. Porcupine Tomato (Solanum pyracanthos)
- Family: Solanaceae
- Annual or Perennial: Annual to tender-perennial
Porcupine Tomato (Solanum pyracanthos) is an annual evergreen shrub that can grow up to 0.30-1.5m in height. It has distinctive orange thorns along the blueish-green leaf veins (about 6-21cm long) on the top and bottom surfaces.
The plant has showy violet flowers and marble-sized yellow berries 1-1.2 cm in diameter. As with many members of the Solanum genera, the weed contains a highly toxic compound, tropane, which is poisonous to humans.
It is native to Madagascar.
Removal Methods
- Cutting: Cutting the weed stems and fruits prevents it from spreading.
4. Japanese Barberry (Berberis thunbergii)
- Family: Berberideceae
- Annual or Perennial: Perennial
Japanese Barberry (Berberis thunbergii) is a perennial woody shrub that grows up to 1.8m in height.
While it’s best known for red flowers and berries, depending on the cultivar, you may come across the yellow-flowered and berried Japanese Barberry.
The plant produces bright yellow leaves about 2-7cm long clustered immediately above the thorns (4-10mm long). All parts of the plant, including the berries, are toxic to humans but show mild impact on animals.
It is native to Japan.
Removal Methods
- Pulling: It’s effective for small clumps and individual plants.
- Mechanical: Cut the plant portion above the ground using a chainsaw or brush mower. You can also pull the above stems and roots using a weed wrench. These methods are often combined with other types of control treatments.
- Propane Torch: Use the heat to kill the above-ground portions of the plant.
- Controlled Burning: Under carefully controlled conditions, prescribed fire can help reduce the size and spread of the weed.
- Herbicides: Apply a treatment containing glyphosate and triclopyr on the foliage or cut stumps for effective control.
5. Yellow-Berried Nightshade (Solanum virginianum)
- Family: Solanaceae
- Annual or Perennial: Perennial
Yellow-berried nightshade (Solanum virginianum) is a perennial herbaceous plant that grows 50-70 cm tall. The plant is armed with copious thorns across the stems, veins, and the stalks of the leaves measuring 0.5-2 cm x 0.5-1.5mm.
The pale-yellow berries are about 3 cm in diameter when fully ripe and poisonous to humans.
It is native to:
- Australia
- India
- Himalayas
- Malaysia
- Polynesia
Removal Methods
- Pulling: Hand pulling is effective for removing young plants or early infestations.
- Cutting: Cut the stems repeatedly to starve the roots or cut and spot-spray with herbicide.
- Herbicides: Apply non-selective herbicides like glyphosate, imazapyr, or triclopyr to actively growing yellow-berried nightshade.
- Mulching: Cover new plants with a thick layer of mulch to prevent growth.
Lead Editor for Insight Weeds.