Can a Kimberly fern be left outside during the winter (if planted in the ground) and what treatment/care would it need?
The Gardener’s Answer
Hello, Brenda: Kimberly Queen ferns are hardy to zone 9, which means they can survive outdoors until temperatures reach 20 degrees F. So for those of us not living in these warmer regions it is good to know that they can be over-wintered quite easily. Over-wintering our tropicals such as a Kimberly Queen fern indoors is a great way to save our plants from year to year. That being said, some of these plants are easier to over-winter than others, but the Kimberly Queen fern is one of the easier ones. The downfall to keeping them indoors for the cold months is that they will likely drop a lot of their fronds, thus more maintenance on your part in terms of cleaning up after them. You can put a piece of plastic under the plant for easy cleanup. Another option is to cut back all the foliage when you bring it inside. Plant growth slows down when temperatures are cooler and in response, less light and water are required. The fern will not likely put on any new growth during the winter months. The idea is to keep the roots alive so it can put on new growth next season. Indoors or out, these ferns do not like to completely dry out so watch your moisture levels. This will depend on the temperature and humidity of your home, but watering every seven to 10 days should be sufficient for the cooler months. You will want to cut back on your fertilizing during the winter months but after your frost-free date passes, take your fern back outdoors, give it a dose of your favorite fertilizer, water it well, and watch it grow. It will likely take a few weeks for it to put on new growth so be patient, but it will once again look lush and beautiful. This upright sword fern is a sun lover but be careful when you take it back outdoors that it gets acclimated to the intense sun; otherwise the foliage will burn.