Thirty years of King Ranch Bluestem (Bothriochloa ischaemum var. songarica) in N. Hays County

by Bob Harms  email-here

Heavily grazed KR bottomland, winter 1977

Since 1977 the state of King Ranch Bluestem (KR) on our 50 acre ranchland in N. Hays County has constantly changed, from badly overgrazed when we first got it, to aggressive invader in the early years after cessation of grazing, and eventually to decrepit old bunches in recent years. One late July burn caused by dry lightning in 1988 led to a revitalization, that is only now showing signs of age. After its initial surge into dominance it has gradually yielded to native grasses in all but a few areas, primarily bottomland with deep calcareous black clay, and even there it is gradually giving way to natives.

Emerging KR fields in late 1977

July 2007 detail of area of 1988 burn

July 2007 detail of area not touched for 30 years
[Green forbs are wild petunia (Ruellia nudiflora) and plateau silverbush (Argythamnia simulans)]

Our 3 decades of experience support the statement in Correll & Johnston 1970 (p. 198):

Widespread along roadsides, where sown by highway department, spring-fall; introd. from the steppes of n. Asia; reportedly a promising pasture grass in s. Tex. but not persisting except in cult. or along roadsides.
Of course, "not persisting" must be taken to mean "over the long run." I suspect that one reason for a recent rash of efforts devoted to KR removal is that as hill country pastureland in the areas close to cities has become gentrified and is no longer grazed, KR currently appears to be a dominant invader, yielding only to the even worse invasion of Ashe junipers or Johnsongrass. No one has the patience to let nature run its course, and I can appreciate the desire for quick remedies by newly arrived land holders. On the other hand, the sky is not falling, and I am unaware of any scientific studies that demonstrate cause for long term ecological concern.

Our experience indicates:

In sum, our 30 year experience with KR in N. Hays Co. indicates that with time the Correll & Johnston prognosis will prove correct.