yes, Belladonna Lilly can be toxic to dogs.
Scientific Name: Amaryllis belladonna
Additional Common Names: Jersey lily, belladonna-lily, naked-lady-lily, March lily
Toxic Principle: The toxic principle of this plant is Lycorine and others.
Poisoning Symptoms include vomiting, depression, diarrhea, abdominal pain, hypersalivation, anorexia, tremors.
Additional Info
Amaryllis are bulbous plants, with each bulb being 5-10 cm in diameter. They have several strap-shaped, green leaves, 30-50 cm long and 2-3 cm broad, arranged in two rows. The leaves are produced in the autumn or early spring in cold climates and eventually die down by late spring. The bulb is then dormant until late summer.
In late summer (August in zone 7) each bulb produces one or two naked stems 30-60 cm tall, each of which bears a cluster of 2 to 12 funnel-shaped flowers at their tops. Each flower is 6-10 cm diameter with six sepals (three outer sepals, three inner petals, with a similar appearance to each other). The usual color is white with crimson veins, but pink or purple also occur naturally. This pattern of flowering at a different time from when foliage appears is the cause of its common name “naked lady”.