While almost all the rivers in Yellowstone National Park have excellent hatches of Mayflies, Stoneflies and Caddis flies, one of the most exciting opportunities for fly anglers is fishing the hopper bloom on the Gardner River. The Gardner is well known scenic trout stream climbing through the northeast slope of Joseph Peak in the northwest corner of the park. For the majority of the headwaters of the Gardner, the river is small, clear and full of tiny brook trout. As you move further downstream closer to the Norris-Mammoth road bridge, the river starts to change becoming swift, boulder-filled pocket water holding rainbows, cutthroat and brown trout. This unique area is what anglers should target when the hoppers arrive in mid-July. The broken water between the boulders is the perfect junction for trout to hide waiting to ambush helpless insects.
Why hoppers are such a target for trout on the Gardner is no mystery. Hoppers are a large, protein packed food item readily available from July to September. Trout will stage near the banks or behind rocks waiting for these critters to get blown into the water. The best areas to target on the Gardner are areas adjacent to fields or open meadows with a lot of weeds or grass. The more grass along the banks of the stream the better the fishing is going to be. Even sections that are not located in such prime grasshopper habitat still are going have some hopper action and fish will keep an eye out for these bugs.
Most grasshoppers are terrible fliers so anglers should be thinking of fishing these patterns on windy days when hoppers have the chance of being blown into the river. Since these insects spend the majority of their lives on shore, fish are not used to seeing tons of flies on the water at one time. Matching the hatch is not absolutely critical but can help if are not getting fish to rise regularly. You can try walking in the grass before you fish to see what is available, or simply start by trying patterns in yellow, brown, tan or green. There are multiple variants of these colors but for all practical purposes these four colors should just about cover it. If you have two or three different sizes of flies in those colors, you should be well prepared for what you will find in and around the river.
To fish hopper patterns on the Gardner River successfully, fly anglers need to understand how to manage the fly line on the water. In most spots on the river you are going to find multiple currents and slow water areas making dead drifting flies a pain. A good technique is to cast quartering upstream to fishy looking areas and use the high stick nymphing technique (keep the rod tip high and fly line off the water). Just allowing the fly to be on the water and not the fly line will give you a much more natural presentation and keep the fly in the strike zone longer.
The Gardner River has many different seasons throughout the year that attract anglers to its banks. During the hot summer months it is hard to beat the action and excitement of drifting hoppers and seeing trout rise throughout the river. The Gardner is an amazing river and if you find yourself in Yellowstone this summer don't miss out on the quality opportunity to catch a few fish.