A lot of people don't know about why lawns are so disliked outside of how they are a waste of water, so here:
carbon emissions put out by lawn mowers (and other devices like leaf blowers). Lawn mowers produce significantly more greenhouse gases per hour of use than cars, and majorly contribute to smog.
Fertilizers get into bodies of water and cause algae blooms, converting all the diverse water plants to homogenous green slime.
Pesticides kill fireflies, bees, and all sorts of other beneficial insects, and many can kill or harm fish, birds and even humans.
Herbicides can have negative effects on the wrong targets too, but they are also causing common agricultural weeds to evolve resistance faster, increasing our dependence on pesticides.
Watering lawns does waste a lot of fresh water.
Lawns replace areas that once could have contained 100+ plant species with monocultures of frequently invasive species. Butterflies can't find host plants this way. Bees can't find food. Thousands of insect species rely on specific plants for food, and no other plant will do. A huge amount of the land is taken up by these wastelands.
Lawns also create dead, compacted, lifeless soil that is hard to grow other things in or near. The root systems of turf grasses are not robust enough to allow water to penetrate in. No matter how much nitrogen and phosphorous you dump on a lawn, it will still be lacking in the organic matter needed to create lush, absorbent dirt.
Dirt is supposed to be full of fungal mycelium. Scientists have discovered recently that the vast majority of all plant species are dependent on a network of symbiotic fungi attached to their roots for 80% of their phosphorous needs and 90% of their nitrogen needs.
Yes, this means that when you put a fungicide on your lawn, you've just nerfed that plant's ability to absorb nutrients by up to 90%. And you've also devastated its ability to absorb water, because plants are partly dependent on their fungi to get water out of dirt.
But fungicide isn't the only problem. Every plant in a natural environment is attached to multiple species of fungus, and most fungi are attached to multiple species of plant (though some are specialists). Trees literally use this system to send nutrients to other trees. We discovered recently that trees in deserts in California can survive extreme drought because they're attached to fungi that can break down rocks and extract water from the rocks.
If you don't have a good variety of plant species and rotting leaves and sticks and stuff, it doesn't matter how much fertilizer you put on it, your soil isn't "healthy" because it's not alive.
Vegetation that has been cropped extremely short doesn't hold in water, so a heavily maintained lawn is likely unnaturally dry for your climate, and a flower or bush in the middle of a lawn without tall grasses, shrubs and weeds nearby is getting pounded by the sun much harder than it's meant to handle.
Yeah, gardening isn't hard, most native plants are falling all over themselves to grow, it's just that the standard suburban backyard is ridiculously hostile to life.
Of course at this point you may be wondering
"What do I do instead?"
Well, here you go:
Stop weeding, spraying and fertilizing. Seriously. Stop it!! Stop it!! Chemical intervention in your lawn traps you in a vicious cycle of creating problems that need to be solved with more chemicals.
"Weeds" are a perfect example. Plants commonly considered "weeds" are adapted to take over areas that have been cleared out of other plants. Many "weeds" are actively harmed by the fungi that other plants depend on, meaning they can ONLY thrive in disturbed or devastated areas. The harder you work to eliminate biodiversity in your yard, the harder nature is going to bomb your yard with weeds.
By the way, google the "soil seed bank." Seeds can stay dormant in soil for years or even decades. If you want a "weed-free" lawn, get ready to apply herbicides for the rest of your life.
Mow less often. You really can't go wrong with this one.
Don't try to grow grass where grass doesn't want to grow. Lots of shade? Try moss. Extremely dry? Try drought-adapted plants. See what wants to grow there and let it do its thing.
It's fine to have a lawn area that you actually use. But if no one walks or plays on a stretch of your lawn, it should be something else. A wildflower patch, a stand of prairie grasses, some large shrubs, a grove of trees.
By the way, the idea that shrubs or flower beds are higher maintenance than lawns is wrong. The neat thing about native species is that once they've gotten settled, you literally just do nothing.
People think flower beds are high maintenance because people almost always underpopulate them. They think that there should be big spaces of mulch in between each plant. In a full sun flower bed that's actually filled to capacity, you shouldn't be able to see the ground. If your plants aren't babies anymore and there's still space, more plants.
if you live in an area that was once forest, PLEASE, plant some trees, and not just one tree. Trees are somewhat like guinea pigs, actually, they don't want to be alone. They send each other nutrients through their roots and screen each other from wind damage.
By the way, the "mature spread" of a tree as told on websites means when you plant it by itself. Trees can generally be planted 6-10 feet apart and be perfectly happy, they'll just grow taller and straighter instead of spreading out. (Look at pictures of forests.) HOWEVER large trees like large oaks should really be 25+ feet from structures and septic tanks
(Trees pop up by themselves in lawns. Constantly. Search for them in a woodland biome and you will likely find baby oaks and maples and other cool guys.)
Trees introduce competition for light into the areas you plant them, helping eliminate the "weeds." You know how fast your lawn grows up and gets weedy when you don't mow it? Yeah, that's partly because it's getting a CRAP TON of sunlight dumped on it with reckless abandon.
A shade garden gets "weedy" WAY slower, and unlocks all sorts of gorgeous flowers that don't thrive in a full sun garden. Fallen leaves serve both as compost and mulch. If you live in the right area for it and have room, you cannot go wrong with trees.
Also also:
Because lawns are such hard packed earth with a very thin layer of greenery and roots on, they are TERRIBLE at rain absorption and cumulatively a suburb full of lawns WILL flood more often and/or quickly than one with more 'natural' gardens like those derin has described
Lawns are also more prone to erosion because the root systems of turf grasses, as mentioned, are terrible at infiltrating deep into the soil, so don't hold it together the way a more robust and complex root system would
Trees are very good for biodiversity and wildlife AND can provide nice shade for a human on a hot day
