FoodSubs states that pink peppercorns and pickled capers are effective substitutes for green peppercorns. Green peppercorns come in four varieties: dried, freeze-dried, packed in brine and pickled in vinegar. Some brands also offer jarred green peppercorns packed in sea salt. Capers are the closest and most effective substitute for pickled green peppercorns, but dried pink peppercorns are more effective in recipes calling for non-pickled green peppercorns.
Ground, dried green peppercorns have a peppery, spicy flavor similar to the flavor of ground white pepper. Fresh green peppercorns occasionally appear in Southeast Asian recipes, but they are difficult to find in other regions. Fresh peppercorns spoil rapidly and remain edible for only one day after harvesting.
Green, black and white peppercorns all come from the peppercorn plant, Piper nigrum. According to the Kew Royal Botanical Gardens, hearty peppercorn plants grow in humid, tropical environments and are native to India. Harvesting the pepper berries before they ripen yields green peppercorns. Cooking the berries before drying turns the berries black. White peppercorns are dried juvenile peppercorn seeds.
According to The Spice House, pink peppercorns are a viable substitute for green peppercorns even though they come from a plant in a different genus. Vibrant pink peppercorns resemble black, green and white peppercorns in size and shape.