MUSTERING INDUSIASM

The title is an instructive pun pointing out two common issues every gardener faces in late summer (1) heat aggravated fatigue/burnout and (2) plant decline -- both normal and gardener induced. I will explain and connect both (the lesson and the problem) using Christmas fern (Polystichum acrostichoides, henceforth Xmas fern) as my profile plant. So, why Xmas fern, and why now? As regards the name, for brevity. Regarding purpose, like the local bakery where Xmas music recently was being played during a long stretch of hot weather, as an attention-getting / misdirection respite, some AC for the mind. Although since I started crafting this essay the heat has abated.  BTW the individual leaflets (the pinnae) of Xmas fern resemble a sleigh or stocking, furthering the winter connection and cooling effect.

Xmas fern is a pteridophyte (meaning plant {-phyte} with leaves resembling feathered wings). As with palms, fern leaves are referred to as fronds. Xmas fern has dimorphic fronds 1-2-feet long/tall -- some strictly vegetative, the other kind heteromorphic, with the fertile section terminal (see middle pic above) and occupying the upper one-third of the frond, with the fertile pinnae much smaller. The number of fertile fronds varies from year to year and according to prevailing conditions -- producing more when conditions are better, fewer to none if not. The pinnae are serrate (toothed) with bristle tips, but occasionally one can find in nature (or for sale) a variant with highly dissected pinnae. That unique and intriguing form (f.) is called incisa -- denoting the incised margins. There has been considerable variation in the degree of lobing in the incised specimens I have seen over the many years, with some specimens more interesting than others. With fronds like that, who need anemones? :) The search is like hunting four-leaf clover, but from my experience the rate of success is less.

The bottom (dorsal) surface of the fertile pinnae is covered with rows of spore producing structures called sori (pl.). Each sorus consists of numerous stalked and clustered spore sacs (sporangia) shielded by a membrane, thus the group in which Xmas ferns and its relatives are placed is referred to as shield ferns. The shielding membrane is called an indusium, ergo the pun indusiasm with its obvious reference to enthusiasm :) The shape and location of the sori as well as the location of the indusium varies within the shield ferns. Xmas fern has a centrally borne vase-shaped indusium (which see). For many other shield fern genera the indusium is marginal (i.e., lean-to or flap-like) and variously shaped for each taxon. Unlike those shown in the pics above, older (more developed) sori will be chestnut to dark brown.

Xmas fern is an evergreen, once-pinnate, rhizomatous (thus perennial) species, with the old dark green fronds eventually flopping -- shortly after the first frost/freeze of autumn. The fallen and encircling old fronds are replaced in early spring by a fountain-like display of new and initially lighter green leaves, revealing themselves via the classic uncoiling (circinate) fiddleheads (see top image above). Notice that the fiddleheads (AKA crosiers) of Xmas fern are shiny and off-white due to the abundance of long tapered smooth epidermal scales. The new fronds arise from the center of the ever-enlarging, albeit slowly, short rhizome with its accumulated frond scars. Upon investigation one would discover that that body, which is sometimes referred to as a crown, is dry brown and seems to consist mostly of the hardened remnant leaf (rachis) bases. The Xmas fern rhizome enlarges and slowly migrates, somewhat like Solomon's seal which is a common associate. And by slow, I mean by centimeters and over many years so, unlike Ostrich fern (another native), no worry about unwanted spreading of Xmas fern. Nor should you remove the old fronds, they assist (still photosynthetic) and provide protection (thermal insulation as well as soil moisture retention). -- See the March 2024 post for a spotlight on Solomon's seal.

Xmas fern is native to eastern North America where it is common in shaded to dappled light locations on stream banks, rocky slopes and in woodlands. And, while the species thrives in rich soil in mesic locations, it can also tolerate some amount of clay and late season dry conditions -- more so if shaded. Xmas fern is also essentially disease- and pest-free (e.g., rarely suffers browsing damage). This attractive, interesting and easy to grow indigenous toughie should be a staple at all Midwest garden centers and a resident of most gardens but, surprisingly, it is underutilized. A primary consideration in using Xmas fern is that it looks much better in a naturalistic setting and, since evergreen, becomes more obvious in the landscape during the drab winter months. Christmas dagger, another less common name, is also easy to cultivate and a great choice for slope stabilization and rock gardens.

Continuing with the fern theme and puns -- mustering indusiasm can be a major gardening problem. Related, the first Monday in September is officially Labor Day in the U.S. and what Americans refer to and celebrate as the end of summer. Occasionally, like this year, the holiday falls on September 1st. But a check of the calendar will show that (1) I am NOT referring to celestial summer and (2) as of September 1, we still have at least 1/4 of the growing season remaining*. The mean first fall frost/freeze, which I hard mark as 32-degrees air temp, is late October for my central Indiana garden. Frost to frost, the mean growing season here is about 190 days, though quite variable and likely to increase. The 25-year average is up nearly five days during the past decade! Here's where one should understand that the average is essentially meaningless to gardeners. It is the extremes and the interplay with rate and duration as well as other factors that matter. Moreover, know that twice in the past decade that truncating change marker (32-degrees) did not occur until well into November. Further, late summer is a time of year when we can expect long rainless periods, not infrequently accompanied by high temps which serve to exaggerate some of the poor choices made in spring by naive "gardeners?" as those specimens by now often look haggard. Tis the season to turn yellow and brown -- both normal and maintenance/siting induced. No amount of watering can undo the discoloration -- damage produced by scorch and water stress. I do my best to avoid those poor choices and worsening neglect -- so should you. Nor can I resist getting rid of most of the unsightly dead and damaged tissue when it does occur since it is conspicuous but have learned to be careful when doing the removal. I recommend snipping since pulling to remove can in some species and specimens cause unwanted damage. For example, on more than one occasion, I have pulled the entire plant out of the ground or container doing so. Finally, know that I like the look of some spent species/specimens and leave them for aesthetic effect (e.g., the mullein {Verbascum thapsus}, one of several weeds I appreciate and encourage).

Moist conditions (adequate water) and pleasant temperature is the norm in spring, but most people DO NOT consider the later season needs of the plant(s) they are selecting and do an even poorer job of siting them (e.g., that exposed south-facing spot near a stone wall or foundation). The ground there will be dry, hot and often hard in summer, especially in you live in a subdivision where contending with crappy dirt/subsoil is the norm. Contrary to what most people want to believe, you cannot and do not buildup the organic content by simply piling on an amendment. Rather it is developed over time (think decades and centuries) primarily from the fibrous roots of forbs and graminoids, assisted by the mining action of vertebrates and invertebrates, especially worms. Organic content of the substrate is critically important because it has a profound moderating effect on soil temp via its ability to retain water and thus be thermally connected to Mother Earth -- yet another instance where comprehending water dynamics will make you a better gardener. Moreover, substrate that cannot get and stay moist results in extreme fluctuation which favors weedy taxa and poor performance. As an example, I was recently at a property where the ground up wood mulch, which looked like pulled pork, had been regularly piled on and in places had accumulated to almost a foot thick -- bone dry and incapable of water absorption or retention. The plants there, even though drought tolerate taxa, were severely stunted and barely alive. The brutal conditions in such circumstances are not what delicate plants, including most ferns, could ever tolerate for long. And by the time mid-summer arrives most people's gardening interest has long since waned, their plants (especially the less resilient {i.e., wimpy} and recently planted specimens) reflecting the apathy and associated neglect.

_____

*If asked, those of us crazy about plants will confirm that gardening can be, and for us is, a year-round activity. It does not stop once the annuals have expired and the pretty colored leaves of autumn fade and fall -- it should be more than about flowering. Each of the many unique seasonal looks in our plant playground as anticipated and special as the one preceding, and there are always surprises accompanying the change -- both good and bad. Surrounded by and being in tune with that magnificent natural progression and rebirth is awe-inspiring and spiritual.  Enjoy and share the experience.