Photo creditKrzysztof Ziarnek, Kenraiz, CC BY-SA 4.0, Original photo, Wikimedia thumbnail; no crop or retouchingRattlesnake-masterEryngium yuccifoliumGrows in potsFlower colorBlue, green or whiteBloomSummerHeight4–6 feetSpread3–6 feetLightFull sunSoil moistureSomewhat dry to moistIn potsYesNative to North CarolinaAdd to my listFull record on Quercus