What temperatures are best for a Crown of Thorns kept outside?
As long as it is kept above 25 degrees, it will be ok. It can only withstand these temps for a very short period. It, really, needs to be kept above 50 degrees to be happy. This collection of articles will help: https://www.gardeningknowhow.com/houseplants/crown-of-thorns/
My plant is different than most in that the leaves are larger and thicker. I've had it for 20+ years and each spring I would cut it down and replant because during the winter the lower leaves would fall and not grow back. It always came back and would be beautiful during the summer, fall and some of the winter. A couple years ago I did the same thing, but this time 5 shoots came out and all produced beautiful flowers. It was the most beautiful plant I have ever seen. Five weeks ago I want away for two weeks and left my plant with a friend. I didn't realized that she had no direct sunlight into her home. When I got back almost all the leaves on each shoot fell off. I was so disappointed. I have cut each shoot off and potted them in half peat moss and perlite. They have all taken. What should I transplant them into and what can I do to get new shoots on each plant. Please help me.
Wow, what a journey of this amazing plant.
Good for you for not giving up!
This article will help you.
https://www.gardeningknowhow.com/houseplants/crown-of-thorns/propagate-crown-thorns.htm
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.
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
My mother recently passed away and left me with a large crown of thorns that had belonged to my great grandmother. I was told that it had never bloomed. I was also told that before the first frost to bring it in and put it in a dark place. When I first got it I wasn't thinking and put it on my deck in direct sunlight and it bloomed. Now I'm second guessing my instructions for the winter. What is the proper way to handle a crown of thorns over the cold season?
Crown of thorns can be grown as a houseplant. https://www.gardeningknowhow.com/houseplants/crown-of-thorns/crown-of-thorns-houseplant.htm. Here are instructions on pruning it if it is too large. https://www.gardeningknowhow.com/houseplants/crown-of-thorns/cutting-back-crown-of-thorns.htm
It is from Madagascar so it tolerates heat and drought well but it is not frost tolerant. If it stays above 32 F where you live, it can be left outdoors. When moving it indoors, give it as much sun as you can or use a plant light to encourage blooms.
I live in Hawaii at 600 foot elevation, and just got my first euphorbia/Crown of Thorns. How often do I water on my drip irrigation, how often do I fertilize, and what fertilizer is best? Is the plant acid loving, and should I add fish emulsion or a chicken manure drench? Mahalo, Tom
Typically, extra fertilization is not necessary. These will thrive in your area, almost unaided. This article will give you more information: https://www.gardeningknowhow.com/houseplants/crown-of-thorns/growing-crown-of-thorns-outdoors.htm
My crown of thorns seems to have developed an interesting variation on a single flower stem, containing multiple smaller, mostly white flowers in a structure similar to that of a panicle hydrangea (as opposed to the usual double flower structure). I want to try propagate this possibly mutated flower stem to see if I can grow a successful cultivar. Am I able to make a viable cutting from just the flower stem?
This article will help you with propagation.
https://www.gardeningknowhow.com/houseplants/crown-of-thorns/propagate-crown-thorns.htm
Why are the flowers on my plant different shades of pink?
This is completely normal. This just happens, and is not cause for concern.
Here is an article for more information on the care of this plant: https://www.gardeningknowhow.com/houseplants/crown-of-thorns/crown-of-thorns-houseplant.htm