Text by Paula Dittrick, TMNCPC blogmaster. This blog stems from an article that first appeared in the August Courier. Photos by Paula Dittrick. Thanks to TMNCPC members Susie Doe, Jerry Trenta, and Lynn Trenta for their expertise.
Seabourne Creek Nature Park features seven types of bluestem of which three are non-native and are closely monitored by Texas Master Naturalist Coastal Prairie Chapter members. Jerry Trenta, TMNCPC Seabourne director, said the most widespread non-native bluestem is King Ranch bluestem (Bothriochloa ischaemum var. songarica).
Susie Doe, TMNCPC member, said Causasian or Australian bluestem (Bothriochloa bladhii) is another non-native bluestem at SCNP that can be confused with KR (B. ischmaemum).
“The two bluestems can be distinguished by the fact that the central rachis of the inflorescence in B. ischaemum is shorter than the panicle branches, while in B. bladhii, the rachis is longer than the branches,” Doe said. The panicle of B. ischmaemum often looks rather fan-shaped with somewhat ascending branches.
B. bladhii has branches often spreading out at right angles (more or less) to the rachis, therefore making the inflorescence look much more paniculate. “Of course, this difference is not apparent when the inflorescence is not ‘open,’” Doe said.
Years ago, Doe assembled a Seabourne plant list that is posted on the chapter web site. The list shows 59 grasses total in Seabourne of which 15 are non-native. The other types of bluestem at the park are:
(Andropogon gerardii) Big Bluestem
(Andropogon glomeratus) Bushy Bluestem
(Andropogon virginicus) Broomsedge Bluestem
(Bothriochloa laguroides ssp. Torreyana) Silver Bluestem or Beardgrass
(Dichanthium aristatum) Angleton Bluestem (non-native)
KR bluestem history
KR’s native origin is the Atlantic coasts of Europe to Pacific shores of Asia. Ranchers and researchers introduced it to Texas for a ground cover and a foraging grass, but it’s a poor-quality cattle food. Scientists say KR bluestem reduces insect diversity and contributes to reduced rodent diversity.
Meanwhile, KR bluestem proved impossible to contain, spreading across much of Texas and into other southern states. Management or eradication of KR bluestem is difficult with KR bluestem growing along Texas roads from Harlingen to Jasper. The Texas AgriLife Extension article outlines management options for KR bluestem.