A TOMATO (6 letters) is a popular greenhouse plant that is widely used in cooking and is known for its bright red color. An ORCHID (6 letters) is a flowering plant that is often grown in greenhouses and is known for its delicate and colorful blooms. Hoya (4 letters) is a genus of plants that are often grown in greenhouses and are known for their waxy leaves and fragrant flowers. CALLA (5 letters) is a type of lily that is often grown in greenhouses and is known for its large, white flower. Smilax (6 letters) is a type of vine that is often grown in greenhouses and is known for its glossy leaves and fragrant flowers.