Published Apr 11. 2012

A New Look at the Grannom

Looking at the early sedge or caddis with new eyes - and a bright color

The Grannom - A sedge or caddis with a bright, green body
The Grannom

The Grannom is a small sedge (caddis to those in USA), which hatches in large quantities in April and is regarded as the first fly to prompt trout to "look up".

The hatch lasts for a few hours, mostly in the morning and usually for 2 weeks in April.

I have, like most fly fishers, used the traditional patterns with a brown body, or one with peacock herl, brown wing and brown hackle, 0n a size 14 or 16 hook.

It caught trout, but in my experience I only had one offer from every ten presentations to trout, which were feeding regularly. I do not wish to catch a trout every cast, but this made me wonder why this type of standard pattern only received a few responses.

My research into the life cycle of the Grannom revealed that in the pupa or nymph stage, the body is green and segmented with thin black bands. On emerging the body remains the same colour, and, only after it has been in flight does the body change to a brown and wings become dark brown. So, perhaps we, as fly fishers, caught a few Grannom specimens to imitate, and these would have had the brown body and dark brown wings, whereas the trout were taking eagerly the emerging fly with the green body! So, I came up with this new pattern.

Early spring - The Grannom hatches right as the trees start getting leaves in April
A brown trout fell - The early grannom hatch make the brownies look up towards the surface
Grannom water

The Grannom

Pattern type: 
Dry fly
Trevor Morgan
size 14 or 16
Black 8/0
black tying silk well waxed and doubled to make it thicker
green seals fur (green highlander as used in salmon flies is fine)
3-4 plumes of dark CDC trimmed so that it is no longer than the bend of the hook
3-4 turns of red game genetic cock, wound in front of the wing

So did this new fly work? All I can say is that on the chalk stream where I fish - the river Avon in Wiltshire, England, on the first trial, 3 of us caught 17 brown trout. It has proved itself consistently ever since then.
Since the Grannom "season" is only a short two weeks, perhaps this fly could be a welcome suggestion to make the most of your fishing. I am not there to rewrite fly fishing books, but, like those who contribute to this web site, share our experiences in the hope that others can achieve the same enjoyment success.



Thanks for sharing this very inspiring web page. I've spent the last three or four years trying to find the right Grannom pattern to no avail, and found the mainstream UK pre-tied market lacking for this particular hatch. I have bitten the bullet and taken up fly tying and this seems like a very good starting point...

The Grannom hatches on parts of the Avon last April really had to be seen to be believed. Trout were gorging themselves, picking the flies off weed and obstructions even in the fastest water, as well as off the top. They were interested in little else except the occasional olive and hawthorn.

Peter Laurie

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