Tying Your Own South Platte Flies — The 8 Patterns Worth Learning
The eight South Platte nymph and dry fly patterns that produce more fish than anything else — how to tie them and why they work on technical tailwater trout.
I started tying flies because I was leaving a small fortune snagged on the Cheesman Canyon basalt — nothing humbles you like watching a $3 fly disappear into a rock. The plan was to save money. That part is debatable; I now own more bobbins than I have fingers. But the other payoff is real: you fish with a lot more confidence when you know exactly what you tied and why.
Here are the eight patterns that belong in every South Platte fly box and are worth learning at the vise.
1. Zebra Midge
The most consistent South Platte producer regardless of season. A size 20–22 hook, black thread body with fine silver wire rib, silver or black bead. That’s it. The simplicity is the point — it matches the midge larva profile that Cheesman and Deckers fish eat constantly.
Tying notes: Use the finest wire you can source for the rib — UTC Ultra Wire in Extra Small. The rib spacing should be even and tight, about 10–12 turns on a size 22 hook. Whip finish directly behind the bead with no collar. Add a small dab of head cement on the thread. Total tying time per fly: 3 minutes once you have the materials laid out.
Why it works: Midge larvae make up the bulk of the South Platte fish diet year-round. The zebra’s black and silver profile matches the natural larva in clear water with high precision.
2. RS2
Rim Chung’s RS2 is a Colorado original — tied in Denver specifically for South Platte fish. Hook: size 20–22 scud hook. Thread: gray or olive. Body: fine dubbing (Antron or superfine) with sparse fibers. Wing: small piece of hen back or hackle fibers. No bead.
Tying notes: The key is sparseness. An overdressed RS2 catches fewer fish than a thin one. Dub just enough material to cover the thread, leaving the hook bend visible. The wing should be small enough that it lies flat over the abdomen without creating a silhouette. This takes practice — my first 20 RS2s were too fat.
Why it works: The RS2 imitates a midge pupa or emerging midge with a specific pattern that Cheesman fish have been eating for decades. It’s the pattern guides reach for when nothing else is working.
3. Bead-Head Pheasant Tail
The universal nymph. On the South Platte, I fish the pheasant tail in size 16–20 with a copper or gold bead. Body: pheasant tail fibers wrapped forward. Thorax: peacock herl or pheasant tail. Wing case: pheasant tail fibers pulled over. Legs: pheasant tail tips tied to the side.
Tying notes: The secret to a South Platte pheasant tail is proportions — the fly should look slim and slightly darker than most commercial ties. Natural pheasant tail fibers vary in color; select darker fibers for the body. The bead size should be proportionate to the hook — a too-large bead ruins the fly profile.
Why it works: Pheasant tail imitates multiple nymph species simultaneously. On the South Platte, it covers PMD nymphs, small stonefly nymphs, and general mayfly nymphs in one pattern.
4. Sparkle Dun (PMD)
The dry fly for the PMD hatch. A size 16–18 hook, trailing shuck of Z-lon or antron fiber, PMD yellow-olive dubbed body, comparadun-style deer hair wing tied in a fan over the thorax. No hackle — the deer hair supports the fly.
Tying notes: The wing tie is the challenge. Deer hair needs to be selected for fine, stiff fibers — elk body hair is too coarse. Tie in the wing directly in front of the thorax dubbing, splay the fibers in a 180° fan, and build a small head of dubbing in front to lock the wing angle. The trailing shuck should be 1/3 the hook length, sparse.
Why it works: The trailing shuck represents a crippled PMD struggling to complete the emergence — exactly what selective Cheesman fish are targeting during the PMD hatch when naturals have difficulty emerging.
5. Elk Hair Caddis
The caddis standard. Hook: size 14–18. Body: olive or tan dubbing (or dubbed peacock herl). Hackle: palmered brown hackle. Wing: elk hair stacked and tied in over the body at a 30° angle.
Tying notes: Palmer the hackle forward in open wraps — 5–6 turns on a size 16. The elk hair wing should be as wide as the hook gap. Stack the hair carefully so the tips are even. Trim the butts at a 45° angle behind the eye. Add head cement to the thread head.
Why it works: The elk hair wing profile matches the natural caddis silhouette and floats high in rough water. The palmered hackle creates a small V-wake on the surface that imitates a skittering adult caddis.
6. Mercury Midge
A variant of the zebra midge with a small glass bead at the thorax instead of a metal bead. For the full breakdown on Pat Dorsey’s original pattern — including tying notes and how to fish it at different stages of the hatch — the mercury midge guide covers everything you need. The glass bead traps air and gives a translucent appearance that matches the gas bubble a midge pupa carries when ascending to the surface.
Tying notes: Small glass beads (1.5mm for size 22) are harder to find than tungsten beads. Loon Outdoors and Hareline both sell them. The body and rib are identical to the zebra midge; only the bead changes. The effect is subtle but noticeable on days when the zebra midge is getting refusals.
Why it works: During active emergence, midge pupae carry a small gas bubble visible to trout. The glass bead approximates this feature.
7. WD-40
A midge-mayfly crossover pattern that works throughout the South Platte season. Hook: size 18–22 scud hook. Thread body: olive, brown, or gray. Wing: mallard flank fibers. No bead, no hackle.
Tying notes: Build the body entirely from tying thread — no dubbing. The wing is a small clump of mallard fibers tied flat over the body and trimmed to length. The result should be a flat, slim fly with a subtle wing silhouette. Quick to tie, easy to lose on the Cheesman basalt.
Why it works: The WD-40 imitates both midge pupae and small mayfly nymphs in a single profile. Its versatility makes it the “when in doubt” pattern for South Platte fishing.
8. Parachute BWO
For the Blue-Wing Olive hatches that run spring and fall. Hook: size 18–20. Body: olive dubbing or stripped peacock herl. Hackle: gray or dun hackle wound around a white antron or CDC parachute post. Tail: dun hackle fibers.
Tying notes: The parachute post should be tied in first, before the body or tail, to give yourself working room. Use white antron floss — it’s visible from downstream and floats well. Keep the parachute hackle turns close to the post; a loose parachute doesn’t float correctly.
Why it works: Highly visible in low light and overcast conditions — exactly when BWOs hatch. The parachute post shows up against the surface film in ways a flush-floating dry fly doesn’t.
Getting Started at the Vise
A basic tying kit — vise, bobbin, scissors, whip finisher, and hook selection — runs $75–$150. The patterns above use a limited material list that overlaps significantly. Starting with the zebra midge and RS2 gives you the highest-value South Platte patterns with the simplest material requirements.
What are the easiest South Platte flies to tie first?
The zebra midge and RS2. Both use a short material list that overlaps, the zebra takes about 3 minutes once your materials are laid out, and they’re the two highest-value patterns on Cheesman and Deckers — so the time you spend learning them pays off fastest.
I tied my first 50 zebra midges badly — and I mean badly, the kind of thing you’d quietly clip off before anyone in the parking lot saw it. Flies 51 through 100 were fishable. By fly 200, they were better than anything I was buying at the shop. The learning curve is real but short, and the return — fooling a fish on something you wound together yourself the night before — is the kind of thing that doesn’t get old. The South Platte hatch calendar shows when each of these patterns is most relevant across the season, which helps you know what to stock the vise with each month. Start with the zebra midge. Future you, standing in the Cheesman flows with a box full of confidence, will thank present you for it.