Michigan Flies

Hatches / caddis

Grannom

A

Brachycentrus spp. (B. americanus, B. numerosus, B. lateralis and others in Michigan)

Also called Mother's Day Caddis, American Grannom, Brachycentrus, Apple Caddis.

The spring caddis of late April through May, with intense but brief afternoon emergences and females that ride the water to lay eggs, which is why an egg-laying dry works so well. Look for larvae hanging on silk lines in fast rocky water before the hatch; a green-bodied caddis larva or a soft-hackle swung through the riffles takes fish as the pupae rise. During the hatch fish a #14-16 tan-winged, green-bodied elk-hair or X-caddis from 2 pm to dark. The chart window runs into July but the heavy hatches are the first weeks; the U.P. runs about two weeks behind.

#12–16afternooneveningdusklarvapupaemergeradultbright green body with pale blonde wing (fresh adult)medium green body with brownish-gray wing (egg-layer)green larva in a square, tapered wood case

Mike Palmer · CC0 · iNaturalist · Lane County, OR · 2025

Timing by region

  1. Southeast Lower Peninsula
    1. J
    2. F
    3. M
    4. A
    5. M
    6. J
    7. J
    8. A
    9. S
    10. O
    11. N
    12. D
    Window
    Apr 6 – Jul 17
    Peak
    —
  2. Southwest Lower Peninsula
    1. J
    2. F
    3. M
    4. A
    5. M
    6. J
    7. J
    8. A
    9. S
    10. O
    11. N
    12. D
    Window
    Apr 10 – Jul 21
    Peak
    —
  3. Northeast Lower Peninsula
    1. J
    2. F
    3. M
    4. A
    5. M
    6. J
    7. J
    8. A
    9. S
    10. O
    11. N
    12. D
    Window
    Apr 20 – Jul 31
    Peak
    —
  4. Northwest Lower Peninsula
    1. J
    2. F
    3. M
    4. A
    5. M
    6. J
    7. J
    8. A
    9. S
    10. O
    11. N
    12. D
    Window
    Apr 20 – Jul 31
    Peak
    —
  5. Upper Peninsula
    1. J
    2. F
    3. M
    4. A
    5. M
    6. J
    7. J
    8. A
    9. S
    10. O
    11. N
    12. D
    Window
    May 11 – Aug 21
    Peak
    —

Flies that match

Gold-Ribbed Hare's Ear (reference photo)Reference photo
Gold-Ribbed Hare's Ear
A
Nymph#8–18NaturalOliveBeadhead

The generalist buggy nymph for Michigan's clinger mayflies and caddis pupae, and MidCurrent lists a #10 to #14 Hare's Ear among winter steelhead nymphs. Dead-drift it under an indicator all season for trout, and as a trailer behind an egg or stonefly for steelhead.

Indicator nymphing · Euro / tight-line nymphing

Reserve · $2.75
Elk Hair Caddis (reference photo)Reference photo
Elk Hair Caddis
I
Dry fly#10–20TanOliveBlack+2

The all-purpose adult caddis for Michigan's May through October caddis season, which Houghton's Manistee work shows peaking in early to mid July with flight heaviest an hour or two after sunset. Carry tan #14 to #16 for Hydropsyche, black #16 to #20 for the spring black caddis, and #8 to #10 orange for October Caddis. Skitter it at dusk when egg-layers are on the water.

Dry fly

Reserve · $3.00
X-Caddis
I
Emerger#14–20BlackOliveTan

A trailing-shuck caddis that sits low in the film, matching Troutnut's advice that Chimarra and Grannom need low-floating emergers because they emerge slowly through the surface. Fish black #16 to #20 midday during the late April to June Little Black Caddis, and tan or olive through summer evenings.

Dry fly

Reserve · $3.00
Grannom Pupa (reference photo)Reference photo
Grannom Pupa
A
Emerger#12–16Bright green body, dark wing pads

Brachycentrus emerges in intense afternoon bursts once water holds in the low 50s, from late April on Michigan charts (Mother's Day caddis), a week or two later in the U.P. Swing or dead-drift a green-bodied pupa toward the surface in the hour before the adults appear, then fish it as a dropper behind an Elk Hair Caddis.

Indicator nymphing · Dry fly · Euro / tight-line nymphing

Reserve · $3.00
Soft-Hackle Wet Fly (reference photo)Reference photo
Soft-Hackle Wet Fly
A
Wet fly#8–16Partridge and orangePartridge and greenHare's ear soft hackle

Perfect Fly lists wet flies among St. Marys Atlantic salmon patterns, and Atlantics feed on caddis and midges from mid July through August. A swung soft hackle covers emerging caddis pupae and Sulphurs on any Michigan river; swing it down and across in riffles at dusk, or hang it below a dry.

Swinging flies (spey / switch) · Dry fly · Indicator nymphing

Reserve · $2.75
Henryville Special (reference photo)Reference photo
Henryville Special
I
Dry fly#14–18Olive body, grizzly palmer, duck-quill wing

A classic down-wing caddis dry with a slimmer silhouette than an Elk Hair, good on flat water for the Grannom and black caddis of May and the Hydropsyche of summer. Dead-drift it in the film, then twitch as egg-laying females skitter in the last hour of light.

Dry fly

Reserve · $3.00