Jamieson, Fausset and Brown on Isaiah 35:7

7. parched ground--rather, "the mirage (Hebrew, Sharab, 'the sun's heat') shall become a (real) lake." The sun's rays refracted on the glowing sands at midday give the appearance of a lake of water and often deceive the thirsty traveller (compare Jr 2:13; Is 41:18).

dragons--rather, "jackals."

each--namely, jackal.

grass--rather, "a dwelling or receptacle (answering to the previous habitation) for reeds," &c. (which only grow where there is water, Job 8:11). Where once there was no water, water shall abound.