Gardening Columnist Sabrina Hahn Issues Critical Correction on Toxic Rat Control Method
Each week, The West Australian gardening expert Sabrina Hahn dedicates her time to solving the most perplexing problems faced by home gardeners across the region. In her latest column, she addresses a serious safety concern, helps a gardener locate a rare plant, and debunks a common myth about kitchen waste in the garden.
Urgent Warning: Red Kidney Beans Pose Severe Threat to Wildlife
Sabrina Hahn has issued a heartfelt correction and warning to readers after being informed by numerous concerned individuals about the dangers of using raw red kidney beans as a rat control method. In a previous column, she had endorsed a suggestion from a reader to mix red kidney beans with peanut butter to eliminate rats, but she now strongly advises against this practice due to its high toxicity.
Key points from her correction include:
- Raw red kidney beans contain a natural toxin called phytohaemagglutinin, which is highly poisonous to nearly all wildlife, including birds, mammals, dogs, cats, and humans.
- This toxin is why many dried beans must be soaked and cooked thoroughly before consumption to neutralize the harmful effects.
- After consulting with a veterinarian, Hahn confirmed that the concentration of phytohaemagglutinin is highest in red kidney beans, making them particularly dangerous.
- She expressed regret, stating, "I have always been a supporter of wildlife, and in future will be far more diligent in recommending any methods of killing rats."
This serves as a crucial reminder for gardeners to prioritize safe and humane pest control methods that do not endanger local ecosystems.
Plant Queries: Marmalade Bush and Struggling Scaevolas
In addition to the warning, Hahn tackled specific plant-related questions from readers. David Main from Albany sought help in finding a full-size marmalade bush, scientifically known as Streptosolen jamesonii (formerly Browallia Jamieson). Hahn advised that these plants are available in nurseries under their updated name and suggested placing a special order if not readily stocked, noting that unless labeled "dwarf," they should grow to full size.
Another reader, Julie Huxtable from Floreat, reported issues with her scaevola plants, where only one out of fourteen planted in October 2025 was thriving while the others had shriveled. Hahn explained that plants, like people, can vary in susceptibility to factors such as fungal diseases, weak root systems, or uneven soil conditions. She added that scaevola varieties can be fickle and newer types may have a shorter lifespan of around two years, emphasizing the importance of consistent care and monitoring.
Debunking Myths: Coffee Grounds in the Garden
Cheryl Berry from Busselton inquired about using coffee grounds for her native plants, particularly grevilleas. Hahn provided cautious advice, noting that while coffee grounds can be beneficial, they should be used sparingly. Key recommendations include:
- Avoid using coffee grounds in pots or applying them too frequently in one spot, as they can gradually make the soil alkaline over time.
- They are excellent additions to compost heaps, where they can break down safely and enrich the soil.
- For grevilleas and other natives, limit application to once every fortnight to prevent potential soil imbalance.
- Worms are particularly fond of coffee grounds, so incorporating them into the soil once a week can boost worm activity and soil health.
This advice helps gardeners make informed decisions about sustainable practices that support plant growth without causing harm.
How to Submit Your Gardening Questions
Sabrina Hahn continues to welcome questions from readers for her Green With Envy column, published every Saturday in The West Australian. To submit a query, readers can write to Ask Sabrina, GPO Box D162, Perth 6001, or email home@wanews.com.au. Please include your full name and suburb for consideration. Due to the high volume of submissions, not all questions can be answered, but Hahn remains committed to providing valuable insights and solutions for the gardening community.
Stay updated with more gardening tips and news by signing up for emails from thewest.com.au, ensuring you never miss an issue of this informative column.
