Possible Clues:

• Plant of dock family
• For the vegetarian who's hungry enough to eat a horse?
• Brownish orange
• Light chestnut
• Horse is in pain carrying king to lake
• Plant or horse for 22
• Acid-tasting salad leaf
• That's a rather weedy, brown horse
• The Spanish put on most pitiful salad ingredient [1,1,13]
• Reddish brown horse