Grannom sedges are prolific
in running water nearly everywhere in trout country. On many waters the
Mother’s Day Caddis hatch is the first big hatch of the season that gets trout
keyed to selective.
Grannom are a cased caddis,
the case square in cross-section. Trout eat the cased larvae when they can get
them, & these are important as imitation on some streams, but the emerging
pupae are, by far, the most important stage of this insect. During emergence,
trout consume the pupae almost exclusively.
On my home water, true to
their colloquial name, grannom season usually begins during the week of
Mother’s Day, continuing until about the second week of June when they
diminish, overtaken by the slightly larger spotted sedge that dominate the
summer hatches.
Grannom adults are generally
#16, with dark-brown to black bodies & light brownish-gray wings with faint
mottling. Pupae are a size larger than adults, the abdomen color ranging from
pale olive, through various shades of olive to bright green, &
pinkish-brown to dark brown through the thorax area & wing holsters.
Grannom are uniform in size
& when trout are keyed on them it is important that the imitation be
exactly the right size. A soft-hackle spider provides a good profile of the
emerging pupae. As color varies within the same population, a perfect color
match isn’t important, though, so that my imitation stands out (without being
too intrusive) among the bazillion naturals it’s competing against for the
trout’s attention, I like to add some brightness through the abdomen portion of
the fly – a bright green or reflective material.
As the season progresses
& emergence slows down, trout will turn to eating more adult sedges,
including drowned egg-layers. So it’s a good idea to carry more than one fly
pattern for grannom.
A swung presentation works
well with grannom. Activate the pupa with short 3-inch pulls or by pumping the
rod as the fly swings under tension. If presenting a drowned adult pattern,
swing it dead-drift. If there are visibly feeding trout, I position 45 degrees
upstream of the target & concentrate on that portion of the swing between
90 degrees (straight out) & 45 degrees, that portion of the swing wherein
the fly is pretty much dead-drifting. If nothing is showing on top I’ll fish
two pupa with a sink-tip or on a long fluorocarbon leader.
Grannom sedges emerge midday
through early evening, with egg-laying flights simultaneous. Here are a few of
my current favorites for meeting them:
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Hook: #14 ~ Thread: brown ~ Hackle: partridge ~ Rib: 2 strands of olive midge flash, twisted & wound as a rib ~ Body: olive rabbit with thorax of red-brown antron |
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Hook: #14 ~ Thread: brown ~ Hackle: brahma hen or brown partridge ~ Rib: fine silver wire ~ Body: 4 strands of olive or pearl midge flash, twisted, & thorax of hares mask ~ Shroud: small pinch of Hareline Shrimp Pink UV Dub ~ Top with 2 gadwall flank fibers before winding the hackle
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Drowned Egg-Layer ~ Hook: #16 ~ Thread: black ~ Hackle: partridge ~ Egg Sack: highlander green UNI yarn ~ Body: 3 strands of black midge flash, twisted, & thorax of dark brown dubbing
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Partridge & Peacock ~ #16 (if tying on short-shank, caddis-style hooks, use a #14 hook) ~ egg sacks on this one are optional, the traditional Partridge & Peacock is reliable when trout are taking adult grannoms
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