What's the downside of shade-tolerant grass?

My backyard has been slowly turning to moss. It’s narrow and mostly surrounded by tall trees, so sunlight is limited. I’ve pruned the trees way back, but I’m also considering putting some shade-tolerant grass seed out there, which seems to be standard advice in these situations.

Is there a downside to planting shade-tolerant grass? Is it inherently less sun-tolerant? Is it more stiff, sparse, predatory, detonation-prone, or…something else that makes it less than ideal?

In the case of perennial rye, which is the grass to plant when all else fails (due to shade). it’s something you have to keep overseeding with it year after year as it will not last on its own. It’s the last chance grass if you must have it.

Not much grows well in shade. Shade tolerant grasses get pushed out easily by moss and fast growing weeds. Finer fescue grass may survive if you don’t mow it too short. Perennial rye is mentioned above, annual rye is often used for overseeding because it grows fast and can outcompete other plants. You’ll find that in rapid grow mixes with some perennial seed and that may be a good way to start a lawn in a shady area. The fast growing annual grass protects the area for the slower growing perennial grass to fill out before the next season.

In my book, if it’s green and low to the ground, it’s lawn and I let it grow whatever it is.

What’s wrong with having a lawn of moss?

My thoughts also. Well, except for some weeds that grow much faster and taller than the grass - those bastards get yanked out when I find them.

Moss as a ground cover can be extremely lovely. Grass is highly overrated, in my opinion, unless you want to play field sports. There are many shade-loving low-to-flat plants you can replace your struggling grass with. They won’t need anything like the mowing/fertilizing/weeding/poisoning routine that people seem to find essential to lawn maintenance.

I have more trouble maintaining the sunny parts of my lawn than the shady parts. I like fine fescues – they are attractive and pleasant to walk on.The spring flowers come up through them, and then they take over for the rest of the year. My shady areas are dappled shade under oak trees, and I’m in New England, USDA climate zone 6. I don’t mow the shady areas very often, and I don’t do a lot by way of fertilizer, etc. I do remove the leaves in the fall, and move them to my mulch pile.

Moss is nice, too. If you have attractive moss and it’s doing the job, I’d stick with it. I find grass withstands more foot traffic, though.

I’m also seeding clover instead of grass. It’s a lot nicer to look at, but won’t do any better in shade than grass will. It’s difficult to switch a whole lawn to clover without killing off all the grass which grows faster, but once a stand of clover gets established it will expand and overshadow the grass. I’d love to get my whole lawn covered in clover, don’t know if that will happen.

I really hate mowing, so I’m also inclined to turn a lot of my yard into a Christmas Tree farm. That only needs mowing once every 7 years.

Hmm, I overseed my lawn with clover from time to time, but I find that clover is less drought-tolerant than grass, and every time we have a drought the grass takes over a lot of what had been clover.

In an equivalent situation to the OP, I’d try going with moss and shade-tolerant groundcovers.

They’re not suitable to play touch football on but have their advantages.

https://www.gardeningknowhow.com/lawn-care/lawn-substitutes/moss-lawn/how-to-grow-a-moss-lawn.htm

From what I’ve seen most “shade tolerant” grass mixtures are various fescue varieties. The main drawback is the lawn won’t “heal” itself, so if bare patches develop you’ll be putting down more grass seed there. It’s also susceptible to “brown patch disease”, a fungal disease that can cause the above noted bare spots.

I am a long-suffering shady back yard person. I’ve tried just about everything, and would be happy with anything at this point. But between the shade and two dogs that role play Godzilla vs. Mothra every day (twice on Sundays) I’m not winning the battle.

Which means mopping paw prints on a daily basis.

A lot of trees in your yard or in close proximity will also suck the moisture out of the ground that the lawn needs.