Wild iris. That's a new one to me. What is the bloom like?
Look for pictures of Spuria Iris. Do you think they're what you have?

You can use a spade and cut away a portion of each clump.

"wild" yellow iris leads me to think Iris pseudacorus, which is NOT native but widely naturalized and considered an invasive species across much of the US. If it IS pseudacorus, then they will typically routinely grow as tall as 5'. Cutting back to maintain a specific size is not generally suggested - these are not shrubs after all - but you can cut them back during their winter dormant period to reduce size and tidy up the planting but they will grow back to full size again the next season.

If you need/want to cut these back to keep to a smaller size and if they are indeed Iris pseudacorus, I'd seriously consider removing them entirely and replace with something else that will stay at the height you desire and is not considered such an invasive species.

Here is a link that might be useful: Iris pseudacorus

I'll second gardengal's recommendation: I'd remove them if they turn out to be iris pseudacorus. They are just too much work to maintain. There are so many lovely irises you can use that are not invasive and troublesome.

That said, irises are not supposed to be sheared off short. They are much prettier left to grow to their natural height. If you don't want tall irises there, you may want to consider planting some short varieties instead. Tall bearded irises are about two to three feet tall.

hmm. Seems like it's not what I thought it was. Maybe a Dietes bicolor?

that description makes sense and the pictures look like the flowers that are on the plant.

The part that is concerning me is the bottom part of the plant is mostly ungrowing leaves that were previously cut and is now a huge clump. Then new leaves grow up.

Here is a link that might be useful: Flowers look like this

Dietes' outer foliage dies and the plant looks better with those leaves pulled off. As it is a clump plant, the clump just gets wider (does not send out runners).

If it's only the height that bothers you, you'll need to replace it with a shorter plant. Unless you like the look of cut-off leaves, browning on the cut edge and eventually dying.

To control Iris pseudacorus, you take away it's water. You manage how much it gets, and you manage the plant.