Question
Dear Bakerplanter,
Happy New Year to start!  I am in Ft. Worth, TX and have a large (2.5 - 3 ft. diam) Sago Palm potted up in a container on my front Porch (Southern Exposure).  Recently we had temps down below freezing.  I wrapped the fronds in towels but unfortunately they have all been frostbitten and turned brown.  My question is, do I keep all the fronds on the plant and pray they turn green in spring or do I cut them back to the growing point.  Will new fronds spring up next spring?  Also, I have some asparagus ferns planted in the ground and they also got nipped by the cold weather.  Should I cut them back or leave them be?  Help if you can.

Thanks,
Bobbie

Answer
Happy New Year to you too, Bobbie. Let's see if I can help you.
To begin....Ft Worth Tx. is in Sunset Zone 33. This means that Winters are not consistent in their degree of chill. Several years may go by with lows in the high teens and low 20's. Then comes a year when frigid air from the Far North sweeps through, dropping lows to somewhere between 0 to 15 degrees. So if you have marginal plants, they will do fine with the cold, but will freeze, when the temperatures drop too quickly or too low.
So let's look at your Sago Palm first. It is not a Palm, but a primitive cone-bearing plant related to conifers. It is hardy to 15 degrees. I suspect that the temperature dropped quickly and stayed cold long enough to not only damage the top but also the roots in the container. Plants growing in the ground soil tend to stay warmer then plants in containers. So, if they are to be protected from the cold the whole container and not just the top need protection. It is unfortunate you weren't able to move it inside. Your question about saving the plant will depend on how much damage has been done. The brown will not turn green again. It is dead. If the roots are still healthy, they may sprout new growth, but it will be years before that growth will be as large as the plant that died. I would remove the dead parts of the plant, and find a place for it to winter over that is above 35 degrees. This means that the soil in the container will remain thawed and the roots will have a chance to grow and heal. A lighted garage or basement is good for this. As soon as danger of frost has past, it can be placed outside again.
Now for the Asparagus fern. It is not a fern. It is in the lily family, the same as edible Asparagus. And just like edible Asparagus, it will survive light frosts, but may be killed to the ground by severe cold. After frost, plants often come back from the roots. So to answer you question, yes, cut them back and let them start from the roots again.
I hope that I have helped you understand a little more about the weather and it's effect on your plants.
bakerplanter