Crown of thorns new leaves are black, dead
My crown of thorns gets plenty of sun in West Palm Beach, Fla., but the new growth from the crown is black, curved and dead. We’ve had a lot of rain this summer and I wonder if that’s the cause.
Certified GKH Gardening Expert
Yes, this does sound like a fungal infection from saturated soils. It can be tricky to treat an infection outdoors. I would recommend using wettable sulfur and dolomitic lime around the plants. This can take a few weeks to take hold, but there will be signs of new green growth when it kills the infection.
This article will give you more information on the care of these plants: https://www.gardeningknowhow.com/houseplants/crown-of-thorns/crown-of-thorns-houseplant.htm