Question
Hello,
In Houston we just recently had freezing temps.  I have two large Euphorbias which were not covered the first cold snap.  The tips have shriveled and lost all its color. One is extremely brittle and there is none of the white fluid when I brake anything. Both plants are potted and are 6ft or so tall.  I am not sure what I should do to help save the plants?? It is really breaking my heart to see the damage to all my cactus and succulents.  I covered everything the second freeze and still see a bit of black on some cactus.  Is there anything I should do? Should I trim the black parts off the cactus?


Thank you for you help!
Jessica

Answer
That is heart breaking.  Euphorbia are cold hardy up to a point but don't tolerate freezing.  The tops are dead.  I would cut the dead part off with  a sterilized knife to where the tissue is healthy without any orange or black coloring.  Then dust the cut parts with a fungicide or even charcoal powder.  keep them in a protected area and look for any rot periodically.  They are dormant at this time of year so I wouldn't water them at all and then gradually start to rewater in 1-2 months. Make sure you cover them if another frost is forecast.  it is usually the combination of frost and wet that does the most damage and the tips are often most effected.

As for the cacti, definitely cut off the black on the cactus.  That is rot caused by some microorganism or fungus that had the opportunity to invade a weakened plant.  Also look for further damage.  The problem with cacti is that they can look perfectly fine for months and then die from damage done in a freeze like you have.  You really need to keep them totally dry.  Cacti don't require any water in the winter.

I think your Euphorbia, but if you keep them outside year round why not just plant them?

As for the cactus, I'm not sure the damaged ones will survive and you probably won't know for sure till they come out of dormancy.
Be sure to cover everything if you kn0w it's going to be very cold.  Good luck.