The main plants that don't like blood and bone are native shrubs, carnivorous plants, peas, beans, and most cacti. The high nitrogen and phosphorus in this feed hurts each group in its own way.
I learned this hard lesson with a young banksia I planted in my front yard. I gave it a spring scoop of blood and bone, and within a month the leaves turned black at the tips and the plant stopped growing for good.
Native Australian plants like banksias and grevilleas grew up in soils with almost no phosphorus. Their roots pull up so much when you add a rich feed that the plant suffers from a kind of nutrient poisoning.
Carnivorous plants like Venus flytraps and sundews live in bog soil that has almost nothing in it. They get their food from bugs, so any added fertilizer can burn the fine root hairs and kill them fast.
Australian Natives
- Phosphorus toxic: Banksias, grevilleas, hakeas, and proteas all suffer when fed standard blood and bone blends.
- Visible damage: Look for black leaf tips, sudden leaf drop, and stalled growth within 4 to 6 weeks of feeding.
- Safer choice: Use a low-phosphorus native blend instead, or skip the feed and rely on mulch breakdown for slow nutrients.
Carnivorous Plants
- Soil intolerance: Venus flytraps, sundews, and pitcher plants live in lean, acidic bogs with almost zero nutrients.
- Root burn: A pinch of blood and bone can wipe out a Venus flytrap in 2 to 3 weeks through salt and nutrient burn.
- Feed bugs only: These plants get their nitrogen from trapped insects, so leave the soil alone and let them hunt.
Legumes
- Self-feeding: Peas, beans, lentils, and clover fix their own nitrogen from the air through root bacteria.
- Bacterial shutdown: Extra nitrogen tells the rhizobia bacteria to stop working, which weakens the plant over time.
- Better result: Skip the feed and let the plants build soil for your next crop, a free bonus from these crops.
Succulents and Cacti
- Lean soil preference: Jade plants, aloes, and most cacti want gritty, low-nutrient soil to grow firm and tight.
- Soft growth risk: Rich feeds cause soft, stretched stems that flop over and rot at the base in wet weather.
- Light feed only: Use a quarter-strength cactus feed once or twice a year if you want any push at all.
These phosphorus-sensitive plants built their roots for poor soils over millions of years. A scoop of rich feed floods their system with nutrients they can't process safely.
Good blood and bone alternatives include seaweed liquid, worm castings, and pellets made for natives. You get a gentle push without the harsh dose of P that hurts soft roots.
I tested seaweed extract on my second banksia after the first one died. Six months later the plant was strong, with bright leaves and new flower spikes on every branch.
For a safe native plant fertilizer, look for blends with a phosphorus number under 2% on the bag. Brands sold for grevilleas and banksias keep the P low on purpose to match plant needs.
Always check your plant's needs before you feed it. A quick search of the species name with 'fertilizer' will tell you if blood and bone is safe for it. If not, reach for a gentler option.
Read the full article: Blood Meal Fertilizer: NPK and Best Crops
