Based on the picture shown on Hiccup's Map for Race to the Edge, Speed Stinger Island appears to be well vegetated with bushes and trees, and possible grass. The is also a large river running centrally on the island.
Speed Stinger Island is mentioned very briefly in Stable Quest called "Hunk of Burning Runes". Stable Quests are an activity that a player can send their non-active dragons on to earn rewards for the game. A special "Rune" can be earned from this particular quest, which can be used later to level up a dragon to Titan Wing stage.
Wildfire raging on Speed Stinger Island! Need help controlling the blaze.