Three species were listed as “imperiled in Illinois” (savanna blazing-star, Liatris scariosa; Pennsylvania buttercup, Ranunculus pensylvanicus; and Northern water-plantain, Alisma triviale). Of these, Northern water-plantain is doing well — it is widely distributed (in the lagoons and Columbia Basin) and seems to be thriving.

Twelve other species were listed as “critically imperiled in Illinois”:

bearberry, Arctostaphylos uva-ursi

pale beardtongue, Penstemon pallidus

royal catchfly, Silene regia

marram grass, Ammophila breviligulata

large-flowered penstemon, Penstemon grandiflorus

queen-of-the-prairie, Filipendula rubra

purple-flowered raspberry, Rubus odoratus

seaside sandmat, Euphorbia polygonifolia

cyperus sedge, Carex pseudocyperus

troublesome sedge, Carex molesta

Weigand’s shadbush, Amelanchier interior

Kalm’s St. John’s wort, Hypericum kalmianum

Of these, pale beardtongue and royal catchfly seem to be limited to single locations and may be declining. Bearberry, marram grass, and queen-of-the-prairie have small but stable populations, each in a single location. Weigand’s shadbush and Kalm’s St. John’s wort have widespread distributions in Jackson Park, but that success seems to be due to active planting by Park District employees or contractors. Large-flowered penstemon and seaside sandmat have significant populations and both appear to be expanding their spatial coverage. Purple-flowered raspberry is particularly notable — it is the most common shrub (in numbers and spatial extent) on Wooded Island and has been thriving since at least 2013. I find these details on the success in Jackson Park of species that are “critically imperiled in Illinois” to be a very encouraging measure of the health of Jackson Park.

life cycle — from seed to reproduction to senescence

annual — a plant that completes its life cycle in a single year or growing season

biennial — a plant that completes its life cycle in two years or two growing seasons

perennial — a plant that persists for multiple years, reproducing annually or on a longer yearly cycle

Non-woody plants may be annuals, biennials, or perennials, but woody plants are always perennials — a plant’s huge investment in wood (basically giant cellulose molecules that are a polymer of glucose sugars) has to be amortized over a number of growing seasons.

Of all the flowering plants in Jackson Park, 75% (414 out of 552) are perennials that bloom at the same locations year after year; only 11% are annuals and 5.5% are biennials. (In this context, human agriculture seems most peculiar — virtually all the plants we grow for food are annuals.) Even if we exclude the woody plants (which are, by definition, perennials), 69% of the plant species in Jackson Park are perennials. If you return to Jackson Park repeatedly over multiple years (as I do), some individual plants become old friends, to be greeted as such when they reliably appear in the same spots at the same time of year, year after year. Many have very deep (1-5 meters long!) taproots that also function as storage organs. Other plants in Jackson Park show a mixed life cycle; e.g., [annual or biennial] depending on circumstances or [annual or perennial] or [biennial or perennial] but these plants constitute only 12% (66 out of 512) of the flowering plant species I’ve identified so far in Jackson Park.

In general, prairies and woodlands tend to be dominated by perennials; Jackson Park nicely fits into that pattern.