The players got all these clues in “POPULAR LITERATURE” in the 1-23-2019 Jeopardy! match:

($200) This palindromic time of day is from the Lain for “ninth hour”
($400) A type of redwood that would be proverbially, up at the crack of it
($600) A hit song had us “workin'” these hours, “what a way to make a livin'”
($800) Brian Williams’ MSNBC show has this title that denotes the last possible moment to get something done
($1000) A 2008 Hillary Clinton campaign ad had a crucial phone call at the White House at this early morning time

ANSWERS: show

The players got all the clues in WATCH OUT FOR THAT TREE!, except the ones marked with an asterisk (*):

($400) Bushmen use the sap of the bottle tree to tip poison these, so I wouldn’t climb it if I were you
($800) Don’t stand under a bunya pine– their branches can drop these weighing as much as 40 pounds
*($1200) Seed capsules from the sandbox tree do this, scattering seed at up to 160 mph
*($1600) Stepping on the sharp fallen these of acacia trees can often cause deadly infections
($2000) When unripe the fruit of the ackee tree can cause this state of low blood sugar, leading to coma & death

ANSWERS: show

Today’s Daily Doubles and more information on Final Jeopardy! on Fikkle Fame’s full Daily Jeopardy! Recap