Recumbent Bladder is a real thing. My primary Bent forum, BROL, has threads dating back more than a decade that address the topic in great detail. All sorts of reasons are given and speculated on. All I know is, it happens to me when on my recumbents, and doesn't happen when I ride a DF.
It's been that way for years, even when I was in my early 30's and didn't have BPH, so I'm not convinced it's related, at least not directly, to the size of my prostate.
For years my only defense was to dehydrate myself so the need wouldn't hit me between available bathroom stops, or for the duration of the ride.
That meant I had to keep my rides to less than 20 miles, or plan my bathroom stops and hydration well ahead of time. PITA.
Now in my mid-50's, my kidneys are thanking me with multiple bouts of kidney stones. Right now I've got 4 of them, none less than 4mm in size, so my doctor's orders are to drink a gallon of H2O a day. If I don't, my pee quickly turns brown. I also get digestion issues if I don't drink enough water (Isn't getting old fun?).
This massive increase in fluid intake means that due to my Recumbent Bladder, I can't ride nearly as far without having to stop.
As for simply peeing in the bushes... Some of my favorite local bike paths are sparse on bathrooms, trees or shrubs, but plentiful on frolicking children or families out for a little fresh air, so dropping my shorts and exposing myself isn't an option I wish to explore any more than absolutely necessary..... or ever.
Then about two weeks ago, I stumbled on a cycling blog post called "Use of external catheter for racing (or just convenience)", and I kid you not, my recumbent riding life was changed forever! OMG, this is fantastic! Now I can just enjoy the ride and not think about how far I am from the next bathroom stop and how much water I can drink.
To be clear, I'm not wearing a complete system with a bag and bunch of hose. I've got the condom part, and about 12" of hose that sticks out of my Spandex riding shorts, just above my knee. I tuck the hose in when not in use so it doesn't show.
I'm thrilled with the results.