Agave americana, or the century plant, is a drought-tolerant, perennial plant used for ornamental purposes. The plant is also called American aloe but does not belong to the same family as aloe. It is characterized by greenish-yellow flowers and spatulate leaves, which are over six inches long. Here’s all you need to know to grow this plant in your home garden.
I. Appearance and Characteristics
Agave americana, commonly known as the century plant, maguey, or American aloe, is a flowering plant species belonging to the family Asparagaceae. It is native to Mexico and the United States, specifically Texas. This plant is widely cultivated worldwide for its ornamental value and has become naturalized in various regions, including Southern California, the West Indies, South America, the Mediterranean Basin, Africa, the Canary Islands, India, China, Thailand, and Australia.
Despite being called “American aloe” in common parlance, Agave americana is not a member of the same family as Aloe, although it falls under the same order, Asparagales.
The common name “century plant” stems from its semelparous nature of flowering only once at the end of its long life. After flowering, the plant dies but produces adventitious shoots from the base, allowing its growth to continue. Although it is called the century plant, it typically lives only 10 to 30 years. It has a spread around 1.8–3.0 m (6–10 ft) with gray-green leaves measuring 0.9–1.5 m (3–5 ft) in length. Each with a prickly margin and a heavy spike at the tip that can pierce deeply. Towards the end of its life, the plant produces a tall, branched stalk adorned with yellow blossoms, which can reach a height of 8–9 m (25–30 ft).
II. How to Grow and Care
Sunlight
Century plant requires a well-lit and well-ventilated environment. If there is insufficient light in the environment, the plant will grow slowly and poorly in a loose shape. Over a long period of time, the generation of chlorophyll will also be affected, resulting in the leaves losing luster and turning yellow and white. Some variegated varieties need to be properly shaded in summer. Otherwise, strong sunlight will burn the leaves, leaving spots on them. These burnt spots are irreversible and will affect the plant’s visual appeal.
In winter, sunlight intensity is relatively weaker, even outdoors. This means you must pay special attention to these changes in the plant’s environment. The plant should be placed where there is enough sunlight even in winter. Providing such good conditions will benefit century plant in its ability to overwinter safely.
Temperature
Century plant is native to the arid and semi-arid tropical regions of the Western Hemisphere. It likes a warm and dry environment and has an adaptable growth temperature of 15 to 25 ℃. At night, it grows best at a temperature of 10 to 16 ℃. A cold and dry winter is beneficial to its reproduction, however, the temperature in winter should be kept above 5 ℃.
Century plant is naturally very strong and does not require much water. During the growth period in summer, however, plenty of water and ventilation should be provided. Gradually reduce the amount of water provided after fall begins and reduce watering even further during dormancy in winter.
Watering
Century plant prefers a dry environment. Ensure that potting soil is acceptably wet when watering by letting the water flow out of the bottom of the pot. Signs of dehydration include leaves going from plump to soft or even appearing to shrink. Soil dries relatively quickly in a well-ventilated environment with enough sunlight, so the watering interval can be shortened if needed.
In summer, century plant’s growing season, watering amount and frequency can be slightly increased. Once fall begins, reduce watering as the plant’s growth rate slows down. It is better to keep the potting soil dry at this time. If the temperature falls to 10 ℃ in winter, it will enter dormancy. If this happens, stop watering and be sure to keep it warm to ensure it survives winter. Start watering again when the temperature rises above 20 ℃ in spring.
Soil
Century plant should be planted in soil that is loose, fertile, has good drainage, and is mixed with mold and coarse sand. This fulfills the plant’s requirements for looseness, permeability of water and air, supply of nutrients, etc. The matrix and ratio for reference are 2/5 Leaf mold + 3/10 pine needle soil + 1/5 coarse sand + 1/10 bone meal.
The soil proportions can also be adapted to the environment where the plant is planted. If the environment is rainy and humid, the proportion of coarse sand can be increased to endure good drainage and avoid root rot caused by the accumulation of water at the roots. If the environment is dry with little rain, the proportion of leaf mold can be increased to maintain moisture in the soil so that the roots will not wither due to dryness.
Fertilizing
It’s best to fertilize century plant during the growing season, which generally lasts from spring to summer. The fertilization frequency is once a month. Under normal circumstances, the best ratio of nitrogen fertilizer, phosphate fertilizer, and potassium fertilizer is 3:3:2. Liquid fertilizer or compound fertilizer can be used with a low concentration level; high levels are detrimental to the growth of century plant. Fertilization is generally not necessary at the end of fall and in early winter. With the drop in temperature, the plant will gradually slow its growth and may enter dormancy, with no need for fertilizer.
Planting Instructions
Century plant has a high germination rate through sowing, which is usually carried out in spring. The optimum temperature for seed germination is no less than 15 ℃ at night and around 30 ℃ during the day. If the temperature falls below 10 ℃ at night and 20 ℃ during the day, the rate of seed germination will be greatly reduced. After sowing, you must cover the surface of the pot with plastic wrap to preserve the warmth and moisture within. After 7 – 10 days, seedlings will emerge.
Century plant grows slowly, so there is no need for frequent repotting. Large particles such as ceramsite with a diameter of about 1 cm can be laid at the bottom of the pot to prevent water accumulation and root rot. plant in pots with good permeability, such as earthenware. The size of the pot should be 2-3 times the size of the plant to ensure that there is enough space and soil fertility for century plant to grow.
Pruning
As new leaves grow, the lower leaves will gradually yellow and finally dry. Removing the old leaves promptly will keep century plant looking good. Leaves that are infected with pests and diseases should be trimmed to prevent infecting healthy leaves.
Propagation
The most common propagation method for century plant is division, which is usually carried out during growing seasons or when repotting. Carefully remove shoots that have sprouted from the leaves of the plant. If a removed shoot has roots and no wound at its base, it can be planted directly into a pot. If a removed shoot has no roots or has a wound, it will need to be placed in a cool and well-ventilated environment for about 5 days for the wound to fully dry and heal. After that, plant it in soil with good drainage and ventilation. It will generally take root in 10 days and survive.
It takes a long time for century plant to grow from a seedling to a flowering plant. Generally, when flowering, century plant will grow one or many long flower spikes. When the flowers are about to die, a cluster of seedlings will very often grow at the top of the spike. These can be harvested and replanted.
Century plant can also be propagated by sowing, but it’s uncommon because it requires a long time to grow from a seedling to an adult plant. Additionally, cross-pollination is required to breed seeds. Seeds can be collected and sowed in spring and will take about 10 days to germinate. As long as the temperature is suitable, the germination rate of century plant is high and seedlings are easy to manage.
Pests and Diseases
Common Pests and Plant Diseases
As a master gardener, one of my most cherished plants is the American Century Plant.
However, just like other succulents, it can succumb to various pests and diseases if not properly cared for.
- Agave Snout Weevil
This insect burrows into the base of the Agave, laying eggs in the stem. Its larvae feast on the plant, leading to irreversible damage and often death of the plant.
Most affected are mature plants, especially ones preparing to bloom their large flowering stalk, an event that happens once in their lifetime.
- Soft Rot
An overly moist soil condition can lead to a condition known as root rot. This disease causes the breakdown and decay of the plant’s roots, impairing its ability to absorb water and nutrients.
To prevent this, it’s recommended to plant Agave americana in pots with well-draining soil or sandy soil, to allow excess water to drain off easily. This tough succulent has a high tolerance for dry conditions and prefers full sun or light shade.
- Leaf Spot
This plant disease shows up as unsightly spots on your Agave’s foliage, marring the beautiful appearance of its leaves. It is typically caused by fungi or bacteria that thrive in warm, moist conditions.
Ensure the leaves, especially the sharp spines and teeth, are kept dry to prevent this disease.
- Scale Insects
These pests latch onto the plant, sucking the sap from its leaves, leaving behind a sticky residue called honeydew that can attract other insects and lead to sooty mold.
They often target the offsets (offshoots or “pups” of the original plant) and can overwhelm a young Agave quickly if not managed.
Common Plant Problems
- Brown Tips
One of the common problems you may encounter when caring for the American century plant is brown tips.
The leaves of this succulent are large and lustrous, but they are prone to developing brown tips when they are too exposed to full sun. To deal with this, it’s best to provide some light shade to reduce the exposure.
- Yellowing Leaves
This is also a common issue in agaves. When the foliage takes on a yellow hue, it suggests that the plant isn’t receiving the appropriate amount of water it requires.
Remember, though species from the Agavaceae family usually exhibit high tolerance to drought, they need occasional irrigation particularly in extremely hot weather.
Sharp Teeth and Spines Damage
A mature Agave americana is naturally armed with sharp teeth along the edges of its leaves and a sharp spine at the end of each leaf. This can be a problem for pets and people, as they can cause injuries.
To avoid any unwanted accidents, it is advisable to place the plants out of pets and child reach, perhaps within rosettes or other safe boundaries in your landscape.
- Limited Space
American Century Plants are large succulents native to Mexico, known as maguey in their homeland, they can grow quite large over their lifetime.
Therefore, they need ample space to thrive. If space is limited, consider potting the plant in a large pot or relocating it to a better position in the landscape.
- Offsets or “Pups”
If you notice that your Agave is producing multiple offsets, or “pups,” this is a good thing! It shows the plant is healthy and ready to propagate.
However, if the plant becomes overcrowded, it may be necessary to remove some of the pups and pot them separately.
Overwintering
Century plants predominantly hail from the warm regions of Mexico, displaying a remarkable tolerance to full sun, as part of the agavaceae family. As such, these agaves require a slightly different overwintering routine.
The optimal soil condition for these plants is sandy, well-draining soil as they are highly susceptible to root rot from overly moist soils.
During the colder seasons, it’s best to keep them in a large pot indoors with some light shade to prevent temperature shock.
Equally important is to limit the watering sessions to prevent overtly damp conditions from prompting rot.
Remember, these hardy succulents prefer their environment on the dry side, demonstrating quite the resilience during their lifetime.
III. Uses and Benefits
- Ornamental uses
Agave americana plants are well-suited for designing beds and borders, rock gardens, city gardens, succulent gardens and Mediterranean gardens. They can be grown in containers to adorn outdoor spaces.
- Culinary uses
Agave americana has various uses starting in pre-Columbian Mexico. If the flower stem is cut before flowering, a sweet liquid known as aguamiel (“lit. ’honey water’) can be collected from the plant’s hollowed heart. This liquid can be fermented to produce the alcoholic drink called pulque or octli used in pre-Columbian Mexico.
In the tequila-producing regions of Mexico, agaves are known as mezcales. Mezcal refers to the high-alcohol product obtained through fermented agave distillation, and A. americana is among the several Agave species used for this purpose. The specific mezcal known as tequila is produced from Agave tequilana, commonly referred to as “blue agave.” Mezcal comes in various types, some of which may be flavored with the intensely pungent mezcal worm.
It is important to note that mezcal and tequila, despite being produced from agave plants, differ from pulque in their sugar extraction techniques and classification as distilled spirits. In mezcal and tequila production, the sugars are obtained by heating the piñas (or hearts) of the plants in ovens, as opposed to collecting aguamiel from the cut stalk of the plant. Therefore, if pulque were to be distilled, it would not be classified as mezcal but rather as a distinct beverage.
Agaves are also found throughout Latin America and are used in similar ways. In Ecuador, the equivalent of pulque is known as guarango, which has recently been distilled as miske.
Agave nectar is marketed as a natural sweetener with a low glycemic index, primarily due to its high fructose content.
- Medical uses
Agave americana contains agavose, a sugar that is isomeric (similar) to sucrose (C12H22O11 ) but with reduced sweetening power, as well as agavasaponins and agavosides. It is used in traditional medicine to treat various ailments, and as a laxative, diuretic, and diaphoretic. However, a comprehensive review of research literature using systematic methods (scientific review) did not find sufficient data to support its effectiveness or safety. It is important to note that A. americana can cause severe allergic dermatitis.
- Fibers
The leaves of A. americana yield fibers called pita, which are suitable for making ropes, nets, bags, sacks, matting, and coarse cloth. They are also used for leather embroidery in a technique known as piteado. Both pulque and maguey fiber played significant roles in the pre-Columbian economy of Mexico.
- Wildlife
The plants serve as protective habitats for birds and small animals. They attract hummingbirds and nectar insects. However, they are deer resistant.
