Fern Propagation

January 2018

Propagating ferns does not always have to be about sowing spores in super-clean, antiseptic media and waiting at least a year for germination. Some have a trick up their fronds!

Many forms of Polystichum setiferum in particular also produce fernlets along the leaf axils of their fronds. These form in the winter. In the wild the over-wintering fronds gradually die down leaving the fresh green fernlets in contact with the soil to root.

We can interfere at this stage.

• The frond is laid across a seed tray of 50% all-purpose potting compost: 25% horticultural grit/sharp sand: 25% propagation-mix bark.
• Gently press the frond into the soil, and cover it with grit to weigh it down and prevent it from losing soil contact.
• Water it, and label the tray with the name of the fern and the date.
• Then place it either below a bench in the greenhouse, or in a shaded cold-frame

Top Tips

Alternatively, if the fernlets are a good size, they can be rooted individually into a plug tray filled with the potting mix as above.

• Cut the stem above the fernlet,  and below leaving a half-centimetre tag.
• Insert it into a plug
• Water it in well and label as above and place below the bench in the greenhouse or shaded cold-frame

By the late spring the fernlets should have produced roots through the bottom of the tray. Plant them into 9cm pots of all-purpose potting mixture plus a little slow-release fertiliser such as Osmocote, water them and put them in the shade.

By the autumn they are ready to plant out, or they can be kept another winter and potted on into 1 litre pots.  When they have filled these pots they will be large enough to plant out.

More Information

• Mill Cottage Plants
• HPS Ferns Booklet
• Sally Gregson Epimediums Book
• National HPS