Question
Last week the local temperatures were in the 60's and 70's so I took my potted sarracenia out of storage, and removed the mulch from my bogs. So of course that means we are going to have a hard frost Friday night.  The high for Friday is predicted to be 39 and the low 16.  The following days have a slow warming trend, with Sunday back in the 50's.  So this deep freeze is really just one day.   

I am not too concerned about the bogs, they are in ground and self insulating, though I will cover them with plastic. My bigger concern is the potted plants in trays. Because these plants were not covered in mulch I am already seeing new growth and flower stalks.  They are in water trays that will surely freeze at that temperature .

Do you think just covering them will be enough protection? Or would the better course of action be to bring the trays back in for the one night. There are upwards of twenty five trays, so I am sure you can understand why I would want to avoid bringing them in for just one night of frigid cold.

I hope this doesn't break the one question rule. I know that I don't have to be very concerned about light frosts, but at what temperature would you suggest covering the plants at night ?


Thanks for all the help

Nicole
90 miles north of NYC where the weather can get stupid

Answer
Hi Nicole,

Bad news I'm afraid.  That is really cold for plants that have already started active growth.  Rhizomes will probably survive, but new growth will be nipped.  We had this happen about three years ago where we had a freak May freeze with temperature drop to the mid-20's.  Plant growers of all kinds, especially wine grape growers, were freaking out.  All of the more mature pitchers and flowers on S. flava and oreophila suffered damage.  The plants bounced back just fine in June, but we had to cut off any new foliage that was damaged.

Covering will help, but going all the way back to the teens is really cold.  It is going to be safest to bring them in.  However, if that is going to be impossible, leave the tough guys outside, and bring the drama queens indoors.  Cover the ones still outside.  Here's how I would choose:

Indoors:  Florida Giant dewthreads, D. filiformis tracyi (We lost a bunch of these this year when we had record setting lows in the single digits), Venus Flytraps, S. psittacina, S. minor, P. primuliflora. and S. leucophylla unless they are in big pots.  S. leuco. Tarnok seems really tough so I wouldn't worry about them.

Outdoors:  S. flava, S. oreophila, S. rubra species, most hybrids unless you've notice any that seem to be less cold tolerant, D. filiformis ssp. filiformis, D. rotundifolia, D. intermedia, and hardy butterworts such as P. grandiflora.

Even if you do get some damage, they will probably come back from it.

Good Growing!

Jeff Dallas
Sarracenia Northwest
http://www.cobraplant.com