Updated: April 17, 2023

Century plants, also known as agave americana, are a popular and attractive addition to gardens and landscapes. These plants are known for their large, striking leaves and their ability to thrive in hot, dry environments. However, if you notice that the leaves of your century plant are turning yellow, it could be a sign of a problem.

Yellowing leaves on a century plant can be caused by a number of factors, including environmental stress, disease, or pests. In order to determine the cause of the yellowing leaves and take appropriate action, it is important to understand the potential causes and symptoms.

Environmental Stress

One of the most common causes of yellowing leaves on a century plant is environmental stress. This can include factors such as:

  • Overwatering: Century plants are adapted to dry conditions and do not require frequent watering. Overwatering can lead to root rot and other issues that can cause the leaves to turn yellow.
  • Underwatering: While century plants don’t require frequent watering, they do require some water in order to thrive. If your plant is not getting enough water, its leaves may turn yellow and wilt.
  • Poor soil conditions: Century plants prefer well-drained soil with good drainage. If the soil is too heavy or has poor drainage, it can lead to root rot and other issues that can cause the leaves to turn yellow.
  • Extreme temperatures: Century plants are hardy in hot, dry conditions but can be susceptible to damage from extreme temperatures. If your plant is exposed to extreme cold or heat, its leaves may turn yellow or brown.

Disease

Yellowing leaves on a century plant can also be a sign of disease. Some common diseases that affect century plants include:

  • Agave snout weevil: This pest can cause significant damage to century plants and other agave species. It typically attacks the base of the plant, leading to yellowing and wilting of the leaves.
  • Leaf spot: Leaf spot is a fungal disease that can cause yellowing and browning of the leaves, as well as spots and lesions on the leaves themselves.
  • Root rot: Root rot is a condition caused by overwatering or poor drainage. It can lead to yellowing and wilting of the leaves, as well as other symptoms such as blackened or mushy roots.

Pests

In addition to agave snout weevils, century plants can be susceptible to other pests such as mealybugs and spider mites. These pests can cause damage to the leaves and stems of the plant, leading to yellowing and other symptoms.

What Can I Do if My Century Plant Leaves are Turning Yellow?

If you notice that your century plant leaves are turning yellow, it is important to take action in order to address the underlying issue. Here are some steps you can take:

  • Check for pests: Inspect your plant for signs of pests such as mealybugs, spider mites, or agave snout weevils. If you find any, take appropriate action to control them using insecticidal soap or other treatments.
  • Adjust watering: If you suspect that your plant is being over or under-watered, adjust your watering schedule accordingly. Make sure that your plant is getting enough water but not too much.
  • Improve soil conditions: If your plant is suffering from poor soil conditions, consider amending the soil with compost or other organic matter to improve drainage.
  • Treat disease: If you suspect that your plant is suffering from a fungal disease such as leaf spot or root rot, treat it with an appropriate fungicide.

By taking these steps, you can help address the underlying cause of your century plant’s yellowing leaves and help restore it to health.

FAQ

How often should I water my century plant?

Century plants do not require frequent watering and are adapted to hot, dry conditions. Water your plant only when the soil is completely dry and avoid overwatering.

How can I tell if my century plant is being overwatered?

Overwatering can lead to root rot and other issues that can cause yellowing of the leaves. Signs of overwatering include wilting or yellowing of the leaves, as well as a mushy or blackened appearance of the roots.

Can I save my century plant if its leaves are turning yellow?

Yes, in many cases you can save your century plant by addressing the underlying issue causing the yellowing leaves. Take steps to adjust watering, improve soil conditions, and treat pests or diseases as needed.