Can anyone tell me what this plant is? I originally thought it was a "tree fern", but a friend explained to me that if it doesn't have a trunk, it's not a tree fern. I still believe it is some kind of fern, but looking all over the internet I can't find a fern that looks like this one. It isn't hard to control using the clippers-and-trowel method, so I'm not looking for advice on chemicals to kill it. I am just curious what to call it.

Details: It seems quite happy here in Calif. (SF bay area) zone 9b. It never forms a central trunk, but just spreads out underground and covers an ever widening territory with new stems. Main stems start out green, furry, and sticky, round cross section, and they turn coppery colored with age. Stems never get thicker than about a half inch, and grow to a height of between 3 and 6 ft.

Edit Most of the IDs suggested here so far don't look to me like my fern because of the following additional info I neglected to mention before:

1) The texture of the leaves is not like many other ferns which have a brittle, shiny, plastic-y surface. These leaves are a little bit soft and slightly furry something like the texture of string-bean leaves.

2) The main stems have quite a length at the bottom which is bare, hairy but with no leaves attached, as shown in the last photo.

3) The growth habit of this plant is unlike most of the pictures I see on the internet of ferns that grow in dense clumps. My fern sends up single stems. They must be connected underground, but above ground they are all separated from each other by quite a few inches. Like this...

clumping vs. separate

Photos: unknown fern

baby frond baby fronds not yet unfurled

branching branching pattern

stem close up of cut stem

spores underside of leaves with spores (you can barely see them, but click on picture to enlarge)

single frond, approx. 5'7"

Here is a typical single frond that I cut off close to the ground. Total height is about 5'7", ground to tip.

  • Yeah, it is one of the "normal" ferns. Here in Europe we have a similar looking quite invasive fern: Pteridium aquilinum. Your is not that one. Your one is an probably of an other family Aspleniaceae (because of the sori). I do not know US ferns. It is just difficult to remove them (but changing humidity, pH, adding manure). Le'ts wait for an identification, then we can check how to control them better. [Note: you have also other fern species]. Commented Jun 6, 2019 at 8:39
  • If you want to control it, glyphosate works. Asulam (or Asulox) is a similar herbicide specific to ferns so it won't damage other plants. Alternatively, cutting it down to the ground twice a year will usually kill it in 3 or 4 years - it's a tough cookie! Trying to dig up the rhizomes is a waste of time, since every small broken bit left in the ground will regrow.
    – alephzero
    Commented Jun 6, 2019 at 9:27
  • 1
    @alephzero No, only curious to find out what it is. It is very easy to control without chemicals - just snip it, and it's pretty (in moderation).
    – Lorel C.
    Commented Jun 6, 2019 at 13:57

2 Answers 2


Looks like bracken to me. It grows so well here in Ca.'s bay area it's often treated as a weed. The tightly curled baby fronds are called Fiddleheads and some folks eat them in the spring when they are young and tender.

  • Looking at the "sori" (the "spore spots") on the back side of the leaves, I don't think so, because bracken seems to put the spores as border outlines along the very edges of the leaf margins, but mine are dots on the underside surfaces of the leaves.
    – Lorel C.
    Commented Jun 14, 2019 at 13:46

Looks like a type of Polystichum fern...spreads by underground rhizomes. Easy to cut with a shovel and discard any unwanted offspring, can pot them and give to friends too! Mine dies back in winter and pops back up along with the hosta in the spring. I have Creeping Jenny under, two hydrangeas flanking, and some heucheras in front in my little shade garden. Recently added a Lenten Rose too. I think the fern will only be a problem if you let it take over your garden. Make it an accent plant, not the superstar!

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