The creamy custard apples popularly known as Seethapazham, Ramapazham and Mullatha belong to the Annona genus. They could be classified as Annona Squamosa (Seethapazham), Annona Reticulata (Ramapzham) and Annona Muricata (Mullatha). A new variety called Annona Cherimoya too has been found to grow in the high ranges.
Seethapazham is generally called sugar apple or sweetsop while Mullatha is known as soursop. As the seeds of sugar apple contain an element that is found in organic manure, they are widely used for making organic fertilizers. Meanwhile, Ramapzham stands out for its vibrant red colour and heart shape. So, it is popularly known as the bullock heart.
The sweet flesh of custard apple has creamy and soft consistency. They are believed to have originated in the tropical regions in the Americas and West Indies. Most varieties of custard apples grow in the fertile soil and tropical climate of Kerala. Mullatha too is widely grown across Kerala considering it's medicinal properties. Both varieties require lots of sunlight to grow. The graft saplings of the custard apple varieties that grow up to 15 feet tall, too are easily available. These would begin bearing fruits within two years.