Dumb cane, also known as dieffenbachia, is a perennial plant valued for its attractive foliage, adaptability to indoor conditions and ease of care. Ingestion of the plant's sap causes temporary paralysis of the vocal chords, rendering the victim unable to speak, hence the plant's common name. Dumb cane typically reaches about 6 feet tall and 3 feet wide if grown in ideal conditions, with each leaf growing up to 18 inches long. Native to South America, dumb cane requires consistent warm temperatures to thrive, making it ideal as a houseplant throughout the United States.
Plant dumb cane in a small 6-inch pot filled with all-purpose potting soil. Keep the plant in a location that receives bright, indirect sunlight throughout the day, such as an east-facing window. Maintain a constant temperature of 60 to 75 degrees Fahrenheit.
Water whenever the top inch of soil is completely dry, about once every week. Soak the soil thoroughly at each watering, then drain away excess moisture to ensure the medium does not become soggy. Reduce watering frequency to once every 10 days during winter.
Feed dumb cane using an all-purpose liquid houseplant fertilizer once every two to four weeks from March through September. Apply at half the dosage recommended by the manufacturer to prevent root burn. Do not fertilize during winter, when the plant is dormant.
Cut back dumb cane to about 6 inches in height if the stem becomes too long and bare, and the plant will begin to regrow shortly after. Prune only during late winter, just before active growth resumes, to minimize damage.
Re-pot the plant during early spring, just as new growth begins, to provide more room for the plant's roots and fresh soil. Increase the size of the container by about 2 to 3 inches each time. Use fresh potting soil to maximize growth and ease the shock of transfer.