A carefully developed hybrid variety that offers an ideal combination of hardiness and tolerance to harsh environmental conditions with good fruit production compared to traditional wild cultivars, making it an ideal choice for tropical and subtropical gardeners seeking high-yielding, easy-to-maintain trees. The tree is medium-sized, reaching 2–3 meters in height under ideal conditions. It grows upright and regular, with a rapid growth rate and partial leaf retention during the winter. It tolerates light frost down to -15°C and relative drought, with a high adaptability to a wide range of soil types provided good drainage, preferably moderately acidic soil (pH 6.6–7.3). The tree is grown from seedlings and begins fruiting early, within one and a half to two years of planting, with full maturity after three years, reflecting its high productivity. The tree typically bears fruit in February, March, and May, producing round fruits, approximately 10 to 15 centimeters in diameter, with pale green skin that turns from white to yellow as it ripens. The skin is softer and smoother than traditional soursop, making it easier to handle and consume. The flesh is a soft, lemony color and creamy texture, with a pleasantly citrusy flavor and a refreshing, tropical flavor. The fruit contains a few hard, light brown seeds. The flowers are small, solitary or clustered in small clusters, and are yellowish-green with a slightly leathery texture. They are hermaphrodite, containing both male and female organs, enabling efficient self-pollination without the need for external intervention. The flowers have a mild fragrance that attracts pollinating insects, but the flowering pattern allows for a high rate of self-pollination without relying heavily on insects. The variety is self-pollinating and does not require additional trees, simplifying cultivation and saving farmers time and effort. With its high tolerance to various environmental conditions, ease of care, and acceptable fruit quality, Mountain Soursop is a smart choice for both home and commercial cultivation, and represents exceptional value among the newly developed Rivers varieties.