Tropicals & Tender Perennials: I really need to know the answers to this question., 1 by JaxFlaGardener

JaxFlaGardener wrote:
I have had this thread on my mind all summer, and will revisit it now to share what I have learned about overwintering bromeliads outdoors.

We had a record cold winter in Florida last year. In my area, the temperatures were in the low 20s F for about a ten day period -- a stretch of cold without precedent in our area and throughout much of the state. I lost a lot of my more tropical plants, but I was able to get most of my bromeliads to survive by some frost and freeze protection measures -- some that I devised and others that occurred naturally.

My bromeliad "grotto" growing on the old oak stumps continues to be one of my favorite and most complete areas of my yard. I was able to protect this planting by erecting a tent using 1.5 inch pvc pipe covered in 6 mil plastic sheeting (available at most hardware stores in large rolls of 50 to 100 ft x 12 ft wide for about $40). Nearly all the bromeliads in this area protected by the tent came through the severe freezes with little damage. I learned that a large tent with a lot of air space provides more protection than a small covering close to the top of plants. The purpose of covering plants is not so much to keep the cold air out; but rather it is to keep warm air in. A large tent has more air space that can heat up by day and cool down more slowly by night whereas a small tent that barely covers the plants will cool down quickly as temperatures drop. I learned this cruel lesson by losing some of my Spathaglottis ground orchids which had made it through previous winters. I will soon be erecting the protective tents for this winter for the bromeliad grotto and will get some photos. I also draped the plants in the bromeliad grotto with lots of "twinkle lights" (the small, thin long lights that pull out of the socket and have contact with two tiny wires). These lights help to raise the temperature in the immediate vicinity of the plants by a few degrees. This winter, I may experiment with putting a small electrical heater in the bromeliad tent on the coldest nights, making sure the heater will stay dry.

Some of the bromeliads in my yard that I didn't cover came through the freezes just about as well as the bromeliads under the tent. These bromeliads survived due to overhanging evergreen vines (native Cross Vine, Bignonia capreolata 'Jekyll' primarily). It was amazing to me that an overhead canopy within about 6 ft above the bromeliads could provide so much protection.

Bromeliads that were in more open locations died back completely to the root crown due to the severe freezes, but many of them regenerated and made new growth from the root system.

Most of my pineapple "plantation" (about 12 pineapple plants, some of which have previously produced fruit) froze out completely, but some of those pineapple bromeliads also recovered from the root systems. I have what I think is a variety of red pineapple (it hasn't ever bloomed or made fruit, and I got it at a DG roundup with no I.D. for the plant, so I'm not sure). That red pineapple bromeliad proved to be especially hardy, barely showing any freeze damage at all even though it was in a mostly open location. It had some minimal cover from the broad leaves of a White Bird of Paradise, Strelitzia nicolai, about 3 ft overhead, but that tropical plant's leaves were destroyed with the first freeze so it couldn't have helped much. The Strelitzia also recovered and returned this spring [a larger S. nicolai (about 12 ft tall) in a different area of my garden was also killed back to the ground with the oldest plants dying out but new growth came from the roots.]

Also, my red starfish bromeliads (Cryptanthus bivittatus - probably the 'Ruby' cultivar) showed little freeze damage though they are in a mostly open location. So, maybe the red coloration in bromeliads can be a guide to choosing cold resistant varieties?

In addition to the especially hardy red pineapple bromeliad, there were also some variegated white/green bromeliads (also unidentified as to species) that survived without much damage in open locations.

So, my opinion from the especially severe weather we had last winter is that bromeliads are more cold hardy than might typically be thought. The long stretch of 20s F temperatures we had were mostly at night with some warming during the day which may not be typical for areas further north, but based on my experiences, I think some bromeliads can probably be grown as far north as 8a, possibly even into 7b if some protection is provided.

A couple of other notes: Be patient with freeze damaged bromeliads and don't throw them out even if they look totally dead. Some of mine that were killed back to the ground are only just now (about a year later) showing good recovery. Don't be too "tidy" with weeding as freezing weather approaches. A canopy of taller weeds around a bromeliad may be enough to provide frost/freeze protection.

(photo: a corner of the bromeliad "grotto" with the bromeliads growing on large old oak tree trunks -- the best method I've found to grow bromeliads outdoors)

Jeremy