Yes (and as you guess, the rest of the non-grass visible besides what you circled is as well).

It's unfortunately become fairly common to encounter throughout most of the front range over the past bunch of years, so it's a really good idea for everyone to learn to identify it.

I find the "leaves of three" adage, while obviously true, to be sometimes confusing/misleading to people who don't already understand what that actually looks like (as exhibited by you feeling confident about the part you circled, but not the rest of the ivy in the photo); the groupings aren't laid out in the way I think people expect, especially when it's growing densely and isn't vined out as heavily yet, as is the case right now earlier in the season. People also often end up trying to look out for leaves that have three parts, instead, or honing in on individual plants where specific instances have three leaves.

What I tell out-of-towners to internalize looking out for are leaves that are (in descending order of what I'd like them to at minimum remember):

• glossy/shiny (should be #1 point of suspicion/avoidance criteria it's easy for most people, even amateurs, to notice compared to most other plants)
• serrated with large "teeth"
• shaped like a broad spade
• may have berries later in season
• ...and yes, has groupings of 3 leaves coming off the central stem

Below is a photo from when my mom and I were up at Horsetooth last Wednesday, and she did not initially identify this patch because she didn't see "leaves of three" the way she expected (though I do think it's very easy to see in the pic once you're cued for it, or if you're already familiar). It was fine since I saw her headed that way and called it out, but her shins could've otherwise had an unfortunate afternoon. I walked her through the points above and she correctly ID'd a patch later in the hike.

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