Drought Defenders

flowers

My flowers are doing well with two exceptions: 1) one of the three orange butterfuly milkweed flowers has died. 2) one of the three great blue lobelia has leaves that develop a white color that gradually takes over the leaf. I have removed it as soon as I see the white on it, but then another leaf does the same thing. I planted the three identical flowers in the same place, so same soil, same sunlight, same moisture.