Caring for a dog is a full time job that many people feel makes having a garden impossible. Dogs and gardens can peacefully coexist with a little bit of care and foresight. Dog owners frequently worry whether the plants they grow will harm their dog, a perfectly legitimate fear. Good research and knowledge about harmful plants enables you to have a prized garden and happy pooch.
The genus Beberis is full of hundreds of varieties of barberry plants that exhibit numerous characteristics, making it hard for the casual observer to believe that these plants truly are related. Barberry plants are, with a few exceptions, woody shrubs that can be deciduous or evergreen depending on the type and habitat. Dark green leaves are characteristic of these plants, with some variation on coloring and embellishment. All barberry plants produce flowers and berries. The berries are used for a variety of culinary and medicinal purposes.
The barberry plant family is closely related to the genus Mahonia. Some taxonomists group these two together, but general consensus among botanists decrees that Beberis and Mahonia plants are distinctly different.
For example, the plant known as Creeping Mahonia, or Mahonia aquifolium, is known colloquially as "Holly-leaved Barberry". Mahonia aquifolium is considered by the American Society for the Prevention of Cruelty to Animals' Poison Control Center to be non-toxic to dogs. Mahonia aquifolium uses the name "barberry" in one of its common names, but is not a member of the barberry family and is not a plant often thought of when the word "barberry" is used. Mahonia aquifolium does not contain any of the toxic principles that berberry plants do.
In a study published in "The Complete German Commission E Monographs", barberry was shown to cause death in dogs when tested at a dose of 25 miligrams per kilogram of body weight. This amount is far greater than what a dog could ingest on a casual walk or even by actively seeking out the plant to eat. The lethal effects are due to a suppressed respiratory and heart function by the presence of the chemical Berberine sulphate, a chemical found in the berries of the plant.
To reach the dosage required to cause death, a dog would have to eat a significant amount of barberry berries, numbering in the hundreds. There is only a small amount of the toxic chemical contained within each berry.
The berries themselves are small and hard to access due to the plant's spiny leaves. These leaves would discourage even the most intrepid of dogs from eating enough berries to cause an issue. Most barberry plants do not produce enough fruit to be toxic, even if the dog were to eat the entire plant.
In addition to the reported toxic effects of berries, the ingestion of barberry leaves by dogs may cause mild stomach upset and nausea. Dogs, by nature, are carnivores and cannot easily process plant matter. The same type of stomach upset would be present, for example, in a dog who has eaten grass. This is not cause for alarm and no additional care is necessary.