Dividing a fern (Dryopteris filix-mas)

I want more ferns for our fern wall and some of our ferns are ripe for dividing. After breaking the bank with our flat renovations and garden last year, I’m keen to save money by propagating from the plants we have (it’s also much more interesting and, as you probably know, I’m a propagation geek…). Dividing ferns is pretty easy, and below is how I do it.

Step 1: Grab a fern

Step forward one of my three year old Dryopteris filix-mas, a native fern that is beautiful and tough as old boots. Well, beautiful except after winter…

IMG_4691

Step 2: identify the different crowns and joins

This Dryopteris had five new crowns this year where it previously had one. You can see them easily, it’s the circles of fronds around growing points. Below is a really clear example from another native fern, Asplenium scolopendrium.

Asplenium scolopendrium crown

Other ferns, like our native Polypodium vulgare, grow from rhizomes which are above or below ground roots that run through the soil with fronds growing off them every few centimetres. These are even easier to divide because you just take a segment of rhizome with a frond attached. Early spring is a good time to divide a fern before its fronds unfurl, before it comes into growth (or in Autumn apparently).

Step 3: Remove from pot (easier said than done sometimes)

It had been stuffed in that little pot for three years and was wedged in so its roots had to be cut with a knife and then the plant forced out with a rod through the drainage hole – it put up a good fight but ultimately it lost…

Dividing fern Dryopteris filix-mas

Dividing fern Dryopteris filix-mas

Step 4: Divide the fern with a clean, sharp knife

Next, with a sterile and sharp garden knife, I cut through the middle of the roots and through the join between the largest crown and the other smaller ones. Making sure they each had a good rootball.

Dividing fern Dryopteris filix-mas

They still have a good root mass each

That would probably do it for most people and you would have two good size plants instantly. Because I was feeling cavalier (and cheap) I wanted more plants, so I cut out two of the smaller crowns too. I know Dryopteris filix-mas is one tough cookie and should continue to grow well as long as the crowns have good roots.

Dividing fern Dryopteris filix-mas

Voila! Four Dryopteris filix-mas divisions, divided from one plant.

Step 5: Plant up with good compost and water well

Make sure they don’t dry out for the next few months while they establish. Ferns prefer moist media anyway, although Dryopteris filix-mas can withstand some drought once established.

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Jack Wallington

I'm an RHS qualified garden designer living in Clapham, London who loves growing plants and designing with them. Follow me on Twitter.

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