I have moved my Boston fern indoor. They have grown too large over the summer. Can I cut them back?
Thank you for your question for Toronto Master Gardeners.
Yes, you may prune your lovely Boston ferns (botanical name – Nephrolepis exaltata ‘Bostoniensis’) and in fact, they may appreciate a light fall pruning to enhance their vigour. Always disinfect your pruning tools to prevent the transmission of plant diseases such as fungi, viruses and bacteria. Remove sap and soil with a damp rag or paper towel and then disinfect the pruner’s surfaces by wiping with a 70% minimum strength rubbing alcohol. Allow to dry before use. Keep alcohol away from heat sources as it is flammable.
Start by removing any dead, discoloured and irregularly shaped fronds at soil level. Consider the fern’s overall natural shape which should be maintained during pruning. Avoid pruning the top of the plant but clip off older side fronds which are shading the new growth, again at soil level. Finish the pruning by clipping the outer edges of the fern to the desired shape. Minimize touching the healthy fronds while pruning to avoid causing brown spots to form on the foliage. Heavy pruning, even to pruning back the entire plant, is best left to late winter, early spring just as new growth is beginning. Throughout the winter, be vigilant to detect any pest problems in order to treat problems early.
You may wish to refer to the following Toronto Master Gardeners Gardening Guides for caring for ferns indoors: