The Tiger Tooth Aloe (Aloe juvenna) is a hardy succulent known for its stacked, toothed leaves and bright green color. When this plant turns brown or reddish-brown, it indicates environmental stress. This color change is a survival mechanism triggered by less-than-ideal conditions, not necessarily a sign of death. Diagnosing the cause of browning determines whether the plant is safely stressed or dangerously stressed, typically involving issues with light or water management.
Light Stress and Protective Coloration
Browning or reddening is often a protective response to intense light, similar to a sunburn. This process, called stress coloration, occurs when the plant produces pigments, such as anthocyanins, to shield its internal tissues from excessive ultraviolet (UV) radiation. The leaves adopt a fiery red, orange, or reddish-brown hue while remaining firm to the touch.
This discoloration usually occurs when the plant is moved too quickly from a low-light spot to direct, hot afternoon sun. The rapid change in light intensity prevents the plant from acclimating, triggering the defense response. While the plant can tolerate this for a short period, prolonged exposure can lead to actual leaf tissue damage, or true sunburn. To prevent this, the plant should be gradually introduced to brighter light over several weeks.
Overwatering and Root Health
Browning caused by overwatering is a serious symptom, indicating the onset of root rot, the leading cause of death for succulents. Unlike light stress coloration, leaves affected by overwatering turn a dark, often translucent brown or black, and feel soft and mushy. The plant’s internal cells become oversaturated, burst, and the tissue begins to decay.
Constant moisture in the soil creates an anaerobic environment where fungal and bacterial pathogens thrive and attack the roots. A sign of rot is a foul, stagnant odor emanating from the soil, caused by the decomposition of the root material. To confirm, gently tip the plant out of its pot to inspect the roots. Healthy roots are firm and light in color; rotting roots are dark brown or black, slimy, and easily crumble away.
Dehydration and Underwatering
Browning can also result from severe dehydration, or underwatering. The plant uses up its stored water reserves, causing the leaves to shrivel and wrinkle. This browning typically presents as dry, crispy brown tips or edges, and the entire plant feels lightweight and lacks plumpness.
The soil in an underwatered pot will be bone-dry and compacted, which is the key diagnostic difference from overwatering. While Tiger Tooth Aloes are drought-tolerant, a prolonged lack of water causes the leaves to flatten and curl inward as the plant attempts to conserve moisture. A plant showing these symptoms needs a thorough drink.
Restoring the Tiger Tooth Aloe
The appropriate restoration method depends on the diagnosis. If browning is due to light stress, move the plant to bright, indirect light or slowly reintroduce it to direct sunlight over four to six weeks. This acclimatization prevents the protective pigments from being produced in excess.
For a dehydrated plant, deep soaking is the remedy; place the pot in water for 15 to 20 minutes to allow the soil to absorb moisture from the bottom up. If root rot is confirmed, immediate action is required: remove the plant from the wet soil and use sanitized shears to trim away all dark, mushy, or slimy roots. Allow the trimmed roots and any open cuts to dry and form a protective callus for several days before repotting in fresh, dry, well-draining succulent soil.
After repotting, do not water immediately; wait at least a week for the plant to settle and begin recovery. Going forward, only water the Tiger Tooth Aloe when the soil is completely dry. This practice helps maintain root health and prevents the recurrence of both dehydration and root rot.