Hibiscus can cause vomiting and bloody diarrhea. Saffron spike is
commonly regarded as non-toxic to felines.

N.B.: Cats usually vomit after eating any plant. Anyone who's seen a cat
munch on grass knows this. It's the amount of vomiting and/or
accompanying symptoms that demonstrate toxicity. If you have even the
slightest suspicion a cat has suffered poisoning, take it to the nearest
vet or animal hospital ASAP.