I'll have to track down what photos I have, but I've been paying attention to this for a while! I'm in Kentucky btw
Mowing frequency matters a lot. There are a number of species can be found in fortnightly-mown lawns but don't seem to survive in weekly-mown lawns. Salvia lyrata, Conoclinum coelestinum, Ruellia humilis are some of these. With increased frequency of mowing, the pool of species that can survive long-term lessens.
Prunella vulgaris is a special case. It has a specific "flat" ecotype that sprawls along the ground that is found in lawns, which is pictured in this post, and which I have seen being incredibly successful in lawns. The tall ecotype cannot survive in lawn environments, but the flat ecotype cannot survive well among taller plants.
The species composition of lawns fluctuates year to year and changes over time. Patches of lawn grass are killed off by extreme drought, disease, etc. and overtaken by other species. Many non-micromanaged lawns have patches of bare dirt at least seasonally, often due to heavy erosion, heavy shade, or the presence of concrete or rock underneath.
The grasses themselves can be really diverse. Lolium arundinaceum is by far the most common in Kentucky lawns, but you'll also see crabgrasses, nimblewill, bluegrasses, goose grass (Eleusine indica--by far the most pavement-tolerant plant I know of) centipede grass, timothy grass, bermuda grass, foxtails, bristlegrass. Most of the grasses will remain entirely vegetative until you stop mowing, at which point you will learn at least vaguely what grasses you have. My yard has quite a lot of some kind of Paspalum, probably more than one species.
Stopping mowing will not get you a diverse community though in Kentucky, as the Lolium arundinaceum will set to work murdering everything else. Mowing frequently actually keeps its violent aggression at bay a bit. Fields that are mowed a few times a year to a year tend to suffer the most horribly from it.
Native sedges are also quite common in lawns. They are hell to identify but there are multiple species in my yard.
Mock strawberry (potentilla indica) is extremely common. Many buttercups are common: Ranunculus sardous, Ranunculus abortivus, and Ranunculus parviflorus in my yard. Viola sororia thrives in even slightly shady areas, and makes up a lot of my yard's lawn areas, Viola rafinesquii is common in some places (notably a vacant lot near the walmart). Can't forget our friends dandelion and white clover. There are also massive amounts of Plantago lanceolata. The other Plantago species don't seem to be present anymore in my yard.
In spring, red deadnettle (Lamium purpureum) and henbit deadnettle (Lamium amplexicaule). These are winter annuals. Kentucky lawns have a LOT of winter annuals. I have at least three speedwell species (Veronica). Multiple chickweed species. Glechoma hederacea in shady areas. Medicago lupulina is present in a lot of areas. Both Oxalis corniculata and Oxalis dillenni are everywhere (Oxalis corniculata mainly appears in areas where grass has died). Some unidentified Polygonums and Persicarias (mostly in damp shaded areas next to concrete)
I also have at least one Erigeron which remains vegetative in regularly mowed areas but blooms vigorously if the mowing is neglected. The vegetative persistence of plants that bloom when they grow tall is a common thing in lawns. A huge amount of my lawn spaces are vegetative chicory and vegetative old field white aster. Thistles and moth mullein also frequently grow vegetatively in lawns in Kentucky.
I have Geranium carolinianum and Sherardia arvensis, which did not appear until they were introduced accidentally by my plant-introducing activities, but have spread merrily since then. This is interesting to me because it suggests that some plants capable of surviving in lawns are limited by dispersal.
The soil seed bank in my back yard seems to be largely agricultural weeds: tillage and fire invoke the growth of Ragweed, Pokeweed, Barnyardgrass, Pigweed/Redroot Amaranth, and MILLIONS of Crabgrasses. For a while, Spurges were everywhere in such disturbed areas, but this year there have been none.
I have a natural seep in the back yard and some kind of Spikerush (Eleocharis) grew there.
I think the frequency of mowing and the presence of shade accounts for much of the variation in lawn species.
My best friend's house has a "lawn" that is almost ENTIRELY Dioda virginiana with some native sedges. I have not seen that anywhere else.
It's really interesting to me. Lawns that aren't full of pesticides tend to be pretty diverse with species! But they don't offer the kind of habitat structure needed by insects, in terms of tall, sheltering plants with stems and leaves of different shapes and sizes and textures. Soil dryness and compaction is also an issue.
stormborns
snowghoul
ellievsbear
pixelskylines
baratheonpilled
titsay
germansingergirl
