The plant commonly known as the Foxtail Fern is scientifically classified as Asparagus densiflorus 'Myersii' or Asparagus densiflorus 'Meyeri'. It is crucial to note that it is not a true fern but a member of the Asparagaceae family, making it a relative of the edible asparagus. This distinction is vital because true ferns are generally considered non-toxic, whereas plants in the asparagus family have specific toxicological concerns for pets. The common name arises from its visual characteristics: its plume-like, densely packed stems resemble a fox's tail.
The primary toxic agents identified in Asparagus densiflorus are a group of chemicals known as sapogenins. Sapogenins are steroid compounds that can be irritating to the gastrointestinal tract. When a cat or dog chews on or ingests parts of the plant, these sapogenins are released. The plant also possesses small, sharp structures that can cause mechanical irritation. The most concerning aspect is the plant's berries. The vibrant red berries are the most toxic part of the plant, containing a higher concentration of these irritating compounds. Ingestion of these berries poses a greater risk of poisoning compared to the stems.
According to the ASPCA's Animal Poison Control Center, which lists the Foxtail Fern as toxic to both cats and dogs, ingestion typically results in gastrointestinal upset. The sapogenins act as irritants, leading to symptoms such as vomiting, diarrhea, and abdominal pain or discomfort. A pet may also exhibit signs of anorexia (refusing to eat) due to nausea. The sharp nature of the cladodes (the leaf-like structures) can cause additional mechanical irritation to the mouth, throat, and digestive tract, potentially leading to drooling or pawing at the mouth.
The ASPCA officially categorizes the Foxtail Fern (Asparagus densiflorus) as toxic to both cats and dogs. This classification is based on the consistent clinical signs of gastrointestinal distress observed after ingestion. If you suspect your pet has ingested any part of a Foxtail Fern, particularly the berries, the ASPCA recommends immediately contacting your veterinarian or the ASPCA Animal Poison Control Center at (888) 426-4435. It is advisable to bring a sample or photo of the plant with you to the veterinarian to aid in accurate identification and diagnosis.
From a horticultural perspective, the safest approach for households with curious pets is to avoid growing Foxtail Ferns indoors or in easily accessible areas of the garden. If the plant is already present, it should be placed in a hanging basket well out of reach or in a room the pets cannot access. Regularly inspecting the plant and promptly removing any developing red berries will significantly reduce the risk of a more serious poisoning incident. Providing pets with safe, alternative greens like cat grass can help deter them from nibbling on household plants.
