I posted this over in the Ferns board but nothing came of it so I thought I'd try it over here and see if I get a response.
I have some very nice aureate Boston Ferns that came to me as the merest "opportunity" to own a plant that any online nursery could have dared to sell. Luckily, they have flourished and I have some very over grown plants now that I'm considering dividing if this possible/advisable.
Can one divide Boston Ferns successfully? If so, any tips will help.
Karl, I have successfully divided a number of Boston ferns. I can tell you that the procedure is messy, brutal, and definitely not for the faint-of-heart. Here goes:
First, knock the plant from its pot, and lay it out on a large surface that you've covered with newspaper. With a sharp knife, brutally slice the fern into quarters. This will give you a better view of the individual ferns that can be cut out and potted. Cut away these small sections. Be brutal.
Next, remove enough of the roots to permit potting each section into a 4-inch clay pot. Use a humussy soil mixture, such as pastuerized leaf mold, lightened with a small amount of perlite.
I have found that new divisions, if given a bright but sunless location, cool temperatures, and adequate humidity, recuperate fairly rapidly. I set them on a humidifying bed of pebbles and water beneath fluorescent lights.
In my experience, two helpful hints. If you can wait until late spring, the new divisions will grow like weeds if you set them outside in light shade for the summer. And, don't be afraid to completely cut off the old fronds of the divisions. They will very quickly grow new, balance foliage. I divide two plants every spring and by June the divisions are huge. I use them in the garden and on the deck, then give them away at the end of the summer. I pot the divisions in at least 8" pots, they grow so fast!
Most definitely. They grow like weeds when spring arrives. Be sure to fertilize them at that time too. Actually, they will start sending out lots of new fronds in late January as the days get longer. That'll be a signal to fertilize them at that time. I think you'll be surprised at how they'll look by summer (Ever wonder how garden centers and big box stores have all of those lush ferns for sale every year, at such cheap prices? Now you know.)
I have a Boston Fern that is now three years old and very large. I am overwintering it in my garage. I am so fearful that if I divide it...that it may die. Will they go for a long time without being divided and still continue to grow and prosper??
Debsroots: I'd be surprised if your fern dies completely, but it will gradually lose it's vigor and decline when it gets too crowded in the pot. (You'll know when the plant starts sending out growth around the edges and out the drainage holes.) If you like keeping one larger plant, rather than dividing it, just repot it into a larger pot in the spring. If it looks ratty, cut back all of the fronds. It will quickly grow a full head of new ones. Boston ferns don't have just one main crown for growth. The plant is made up of lots and lots of smaller crowns, so when you divide it you don't have to worry and can just hack it into pieces. And when it's cut back, each of the small crowns grow back out to make a full plant again. Be sure to fertilize it in the spring when you repot or divide or cut back. I use a 3 month time-release like Osmocote, but you can alternatively use a diluted solution every time you water, or normal mix every two weeks during the growing season.