Ferns comprise a large group of non-flowering plants native to six continents, often associated with moist soil and high humidity. Deciduous ferns' fronds are killed by winter frost or drought but regrow in spring with the return of warmth and rain. Evergreen ferns retain their fronds year-round. Ferns do not repair any damaged parts of their feathery fronds, so the damaged or dead tissues linger. New fronds emerge from the rhizome root when conditions are favourable. Trimming or cutting back your fern depends on your desired outcome: tidying up the plant or rejuvenation.
Trim away any dead or unsightly broken fronds from the fern anytime during the growing season from spring to fall. Snip the frond at the stem base with hand pruners. Do not cut low on the stem or you may accidentally cut or damage the rhizome from where the frond grows.
Wait until fall frosts and freezes turn your ferns' fronds grey or golden brown. Once you decide the dead and dried fronds no longer look ornamental, cut all frond stems to a height of 1 to 5 inches tall with hand pruners. Again, do not harm the rhizome. You can leave the cut frond debris remain on the soil over the rhizome to decompose and benefit the fern and soil next spring.
Reduce the size or number of fronds in the fern clump from spring to fall selectively by cutting fronds back or removing entire fronds from their base. Fern fronds regrow best in spring and early to midsummer, so think twice before trimming or cutting back fern fronds in summer or fall since new fronds won't replace those you cut away.
Trim away any dead or unsightly broken fronds from the fern anytime during the year. Snip the frond at the stem base with hand pruners. Do not cut low on the stem or you may cut or damage the rhizome from where the frond grows.
Cut back all older frond stems to a height of 1 to 3 inches in very late winter or early spring. Do this every other year, according to Collier's Nursery in Alabama. Don't cut off young, shorter, attractive fronds that will grow more -- focus on cutting back the oldest, floppy or ratty-looking fronds. Don't worry, new fronds will soon grow and rejuvenate the overall lushness of the frond in spring and early summer.
Thin out the clustering mass of fronds in the evergreen fern during summer as needed to keep the plant looking its best. Snip fronds at their bases with the hand pruners, taking care not to accidentally cut nearby frond stems.
The best time to cut back deciduous ferns is after fall frost: this can be anytime during winter up until spring when new fronds are expected to unroll from the rhizome. The ideal time to cut back evergreen ferns to rejuvenate is in very late winter to early spring. New fronds will soon grow to fill in the gaps created by the harsh pruning as spring warms and soil remains moist.
Cutting back fronds on ferns actively growing from late spring to fall harms the plant since it no longer makes food via photosynthesis. Done too frequently or at the wrong time, you deplete the rhizome energy to make more fronds or to overwinter or survive a dormancy after a drought. Don't cut back fronds during a drought. This puts stress on the fern, as the plant will attempt to expend energy and resources to grow new fronds at a time when it should be dormant and not actively require roots to absorb moisture from already dry soil.