ANIMALS AFFECTED: Horses are particularly at risk, but all animals ingesting the plant may be poisoned.
DANGEROUS PARTS OF PLANT: Leaves, especially wilted leaves, young shoots, pods, seeds, inner bark.
CLASS OF SIGNS: Depression, poor appetite, weakness, paralysis, abdominal pain, diarrhea (which may be bloody) and abnormalities in the heart rate and/or rhythm. Death is possible.
PLANT DESCRIPTION: These moderate-sized trees with rough bark often bear two short spines at the base of each leafstalk (easiest to see on young leaves). Leaves are alternate and pinnately compound with oval, entire leaflets (fig. 48). The fragrant flowers are creamy white, sweet-pea-like, and arranged in long drooping clusters. The fruit is a flat brown pod which contains kidney-shaped beans (fig. 48A). Black locusts are common in well-drained woods, thickets, and waste areas, especially in the southeastern part of the state. They are often planted along highways and fencerows as ornamentals and for erosion control.
I have never tried this, but I've read in multiple sources that the flowers (and only the flowers, apparently) of black locust, as well as those of wisteria, are edible. Dipping them in batter and frying is the traditional way to prepare them....
Seems like. From personal experience, I've seen my father's horses and cows take the occasional nibble (cleaned the suckers right out of their field) and they're still perfectly healthy, but they're in a large pasture with plenty to eat, so they're not likely to overindulge in anything. I feel pretty confident letting my goats eat them given that goats seem to have a higher tolerance for toxins than many other animals. I do wonder if there are other factors - soil/weather/etc conditions that contribute to toxicity. My father swears they don't make good fence posts either, that they just rot. I haven't tried that yet, my trees are babies, but maybe the toxins just aren't as concentrated in the trees here or something. I have to admit, the conflicting info all over the web and the not-knowing are one of the reasons I planted some. Curiosity gets me every time.
I am a woodworker in addition to being a gardening nut. When my wife and I lived in Virginia she accidentally used a big pile of jointer shavings to mulch a big section of our vegetable garden - within a week nearly everything, with the exception of a few weeds was dead. Similar to what happened when she put black walnut on the flower bed. We learned a few lessons the hard way.
Location: Deepwater northern New South wales Australia
Goats can definitely eat black locust in large quantities. Yes the blooms are a delicious edible, raw or cooked. My favorite use of them was a pesto of Locust blooms, black walnuts, and a little honey.
Re:rot-resistance, they'll rot more or less as fast as anything if the wood is from young trees (younger than 20 years). Younger trees are called Yellow locust, colloquially, because they are mostly sapwood. Older trees are called Black locust, because at about 20 years they seem to drastically increase the ratio of heartwood:sapwood. It is the heartwood that is extremely rot resistant. I know of farms in my area where the fence posts are 100 year old Black locust, in clay, in a temperate rain forest. They are still solid.