Rock Morning Glory (Ipomoea pandurata) is a resilient perennial vine native to North America. It is also known as Wild Potato Vine and Man-of-the-Earth. It thrives in various environments, showcasing remarkable adaptability. As a twining plant, it can cover ground or climb structures, making it a versatile addition to landscapes. Its vigorous nature and attractive blooms make it a robust native option for gardeners.
Identifying Rock Morning Glory
Rock Morning Glory is recognized by its unique physical attributes, particularly its substantial root system. It develops a large, starchy, tuberous root, often several feet deep and weighing 20 to 30 pounds, which is why it’s called “Man-of-the-Earth.” Above ground, it forms a twining or trailing perennial vine up to 30 feet long. Stems are often hairless and may be reddish-purple.
Leaves are typically olive green, heart-shaped, cordate, or occasionally fiddle-shaped, measuring 3 to 6 inches long. They are attached by long, sometimes purple-tinged, petioles. From late spring to early fall, the vine produces distinctive funnel-shaped white flowers, 2 to 3 inches across. Each flower features a prominent pink or reddish-purple throat, contrasting with the white petals.
Ideal Growing Conditions
Rock Morning Glory adapts well to various environmental settings, preferring ample sunlight. It thrives in full sun, requiring at least six hours of direct sunlight daily; 10 to 12 hours is ideal for prolific flowering. While it tolerates partial shade, too much shade can stunt growth and reduce blooms. It is not particular about soil type, growing well in average, well-drained conditions.
It prefers loamy soil but tolerates poor or rocky soils, contributing to its “rock morning glory” common name. An ideal soil pH ranges from slightly acidic to neutral (6.0-7.0). Once established, it exhibits considerable drought tolerance. It is hardy in USDA Zones 4 through 9 and tolerates moderate humidity.
Planting and Ongoing Care
Rock Morning Glory can be cultivated from seed or root divisions. When starting from seed, scarify the hard seed coat (nicking or sandpaper) and soak seeds in tepid water overnight. Seeds can be sown indoors four to six weeks before the last spring frost or directly outdoors once soil temperatures reach 65°F or above. Plant seeds 1/4 to 1/2 inch deep, spacing them 6 inches apart.
Root division is best performed in fall or early spring. Dig up tuberous roots and cut them into pieces, ensuring each section has at least one “eye” or growing point. After planting, water thoroughly to settle the soil, keeping it consistently moist until established. For established plants, allow soil to dry out almost completely between waterings to prevent root rot, typically watering weekly or more during hot, dry periods.
Rock Morning Glory has minimal fertilization requirements; a balanced liquid 10-10-10 N-P-K fertilizer can be applied monthly during the growing season. Avoid over-fertilizing, which can promote excessive foliage at the expense of flower production. Pruning helps manage growth and encourages a bushier habit; do this in early spring before new growth emerges. Remove dead or damaged stems and trim long vines, ensuring at least three leaf nodes remain above the cut to promote new blooms. Provide a trellis, fence, or other structure for the twining vines to climb and display their full potential.
Addressing Common Problems
Rock Morning Glory is a robust plant with good resistance to common pests and diseases. It typically experiences no major insect or disease problems. However, it can be a host for the sweet potato weevil.
One aspect to manage is its tendency for extensive spreading. Its large, deep tuberous roots can make it difficult to eradicate once established, earning it a reputation for being somewhat weedy. The plant also readily self-seeds in warmer climates; unchecked seedlings can become problematic. To control unwanted spread from seeds, deadhead spent flowers before they form seed pods. While drought-tolerant, maintaining a proper watering schedule prevents issues like root rot from persistent overwatering.