Dioscorea Mexicana (The Turtle Plant)

This plant falls under the category of Dioscorea, known as Caudiciform. Dioscorea in this category has a caudex that is entirely above the ground. This caudex is thick, woody, and dome-shaped. It looks somewhat like a yam that grows on the surface. The Mexicana’s caudex has polygonal sections like a tortoise or turtle shell. This is why its common name is either Tortoise Plant or Turtle Plant depending on which is common among the people naming the plant. It is also referred to as the Mexican Yam due to its outer appearance. Dioscorea Mexicana is a vine-like yam plant that also contributes to its name.

The Turtle Plant is dioecious, which means that every individual plant is either male or female and pollination occurs when pollen moves from the male to the female plant. This means that it is impossible to propagate the plant if you only have one of them.

Origin Of Dioscorea Mexicana

The turtle plant is a native of the arid lands of Mexico and Northern Columbia. Still, it has been exported to many countries worldwide for its unique appearance and many uses.

Why Is Dioscorea Mexicana Useful?

Besides its unique appearance, Dioscorea Mexicana has high medicinal value. It is rich in diosgenin which is a steroid. Also, diosgenin is one of the critical ingredients for synthesizing essential hormones, including progesterone and cortisone. People in the regions where the plant occurs naturally have been using it as a female oral contraceptive.

The diosgenin is found on the root of the bulb. Having noticed its effectiveness as a traditional oral contraceptive, chemist Russel Marker pioneered synthesizing estrogen from naturally occurring diosgenin. This contributed to the production of estrogen, which made birth control much more affordable to women globally. The hormone also helps to control osteoporosis.

The Mexicana variety of Dioscorea is used for medicinal and decorative purposes and as food. Dioscorea Mexicana’s caudex is edible, and it tastes like sweet potatoes. On the other hand, the roots have high diosgenin content, making it difficult for people to eat because they are bitter.

Features Of Dioscorea Mexicana

#1. The Caudex

In its initial stages, the caudex doesn’t have a dome-like appearance. This appearance forms more and more over time and takes its final appearance at the maturity of the Dioscorea Mexicana. The polygonal sections of the caudex are often separated by fault lines that get deeper and deeper with time.

This caudex is an adaptation, a reservoir for water and food, enabling the plant to survive dry seasons. The harness of the caudex protects the plant’s stash from predators. To you as a household gardener, the caudex gives the plant an exotic appearance that accentuates the décor of your home. The caudex can acquire a diameter of more than a meter!

The caudex is the part of morphology that gives the turtle plant longevity. It can be around for a few hundred years if it stays in its natural environment. The evolutionary purpose of the caudex is to help the plant store water and food in the dry and relatively lean climate in which it lives.

#2. The Shoot

The nature of the shoot coming from Dioscorea Mexicana is another reason why the plant is referred to as the Mexican Yam. It is a slow-growing climber with heart-shaped leaves. The leaves are bright green with a glossy surface. The shoot dies in winter, shoots again later in spring, and remains through summer in natural conditions.

Remember that this plant can live for hundreds of years. If they have been in the local environment for a long time, they are likely to have adapted to the local conditions. The adaptation helps them change their growth rhythm and shed the leaves at the appropriate time, locally. If, for example, the plant is in the tropics, it might have some leaves for a longer time in the year than when it grows in its natural habitat.

The coiling tendrils proceeding outwards from the vine seeking support only serve to accentuate the beauty of the yam. This combination of the caudex and the shoot serves a perfect decorative purpose, and that is probably why you are here; you want to see how to take care of this beautiful plant.

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How To Care For Dioscorea Mexicana

#1. Placement

Dioscorea Mexicana grows in partially shaded environments in some dry regions of Latin America. It would help to give the plant the same setting when domesticating it. Could you keep it in a partially shaded place? Direct sunlight all day isn’t healthy for it. It is, therefore, advisable to keep it on your southern or western windows where the sun rays will be partial. The high-noon sun is unhealthy for the plant, and you should shield yourself.

Dioscorea Mexicana performs best in warm temperatures between 18 and 25 degrees Celsius (64.4 – 77 degrees Fahrenheit). It also does well under 12 degrees Celsius (53.6 degrees Fahrenheit) temperature during its season of rest. It is advisable to take the turtle plant outside to bask in the sun once in a while. Please don’t leave it there. Could you bring it back inside the house?

#2. Training

Dioscorea Mexicana is a climber for which you need trainers to keep upright. You can get thin bamboo sticks to keep it in place. The tendrils then coil on it and give your garden an all-natural look. You can also decorate some posts as you like and use them for training the vine.

If you don’t train it with a trellis or bamboo sticks as earlier suggested, its growth is somewhat chaotic because it is meant to climb. This disorganized growth covers the caudex and makes the leaves and tendrils, the most beautiful parts of the plant, invisible.   

#3. Pottage

This plant performs best in highly permeable soil. You can plant it on commercial cactus earth fills that meet the permeability requirement optimally. If this is not available, you can add sand or coconut fiber to the soil you want to plant the Mexicana. It doesn’t do very well in highly nutritious soil, and you can whittle down the regular pottage soil with peat or quartz sand before you plant your Dioscorea Mexicana.

#4. Watering

This plant is succulent, and it can stay for a few days without water. It would help reduce watering when it is in its season of rest but let your watering be more regular in spring and summer when it grows. It is crucial to avoid waterlogging because it can cause root rot; thus, even regular watering during the growth spurt should only be moderate. Also, check to ensure the substrate is dry before your next watering.

#5. Fertilizers

We mentioned that Dioscorea Mexicana doesn’t do well in very fertile soils, and you should have this truth in mind when applying fertilizers. Apply cactus fertilizer in liquid form in the growing season, never during rest. Apply the fertilizer every three weeks in spring and summer. Use fertilizer when the pottage is wet for the best results. If you have recently repotted the plant using a fresh substrate, you don’t need to fertilize it for one year. The nutrients in the soil will be enough for the following year. You stop enriching the soil with fertilizers when leaves start to turn yellow.

How To Propagate Dioscorea Mexicana

As we mentioned earlier, the Turtle Plant is dioecious. This means a single plant can’t facilitate reproduction using cuttings like many succulents. It would help if you used seeds that result from the pollination of plants of different sexes.

It is vital to find sellers with certified seeds and buy from them. The Dioscorea plants in your garden are unlikely to produce seeds as the conditions seldom allow it.

Planting Dioscorea Mexicana The Right Way

• Take a pot or tray, put a thin substrate, and add coconut fibers to the substrate.
• Take the seeds and put them in the substrate, about one centimeter deep. Could you not treat them?
• Cover the seeds with a thin layer of sand and water.

Once you are through planting, keep the planter in partial shade and maintain the temperature at 25-30 degrees Celsius (77 – 86 degrees Fahrenheit). Humidity should also be relatively high, and the best environment to meet these conditions is in a small, well-lit greenhouse.

The seeds should germinate between four and six weeks of planting. You can remove the shade coverage you had put in place to facilitate germination because it creates a humid and warm environment around the young seedlings. Such an environment is destructive for the young seedling.

It would help if you watered the seedlings below by putting the trays or pots where they are growing and dipping them in a more extensive water container. The water should be just enough to allow the seedlings in their container to sit comfortably in it. The pot and trays are usually porous, and the water will seep through to the substratum, thus giving the seedlings a drink from below. Watering ensures that the weak seedlings don’t get washed away by the water you rinse from above.

Transplanting

The caudex is one of Dioscorea Mexicana’s main attractions, and it needs space to grow. Thus you will need to transplant the seedlings to give the plant more room to produce the caudex. After germination, four to six weeks after germination, the plant has its first true leaves: these heart-shaped, glossy leaves and the plant’s rapid growth in general demand transplanting.

Take a pot and fill it with cactus clay made permeable using soil or coconut chaff; use the kind of substratum we described above on which the plant should grow. Moisten the pottage and make a hole using a tool. The hole should be big enough to accommodate the seedling roots without disturbing them. Put back the soil and let it grow. The caudex starts to form about three weeks after transplanting.

Repotting & Pruning

You might need to repot the plant if the caudex outgrows the container you have grown. It grows well after repotting, and all you need to do is put the right kind of soil in the pot, water it as necessary, and ensure you water the ground well.

Dioscorea Mexicana doesn’t require much pruning because it dies once every year. The foliage is, therefore, not much. You should, however, remove the leaves that dry up during the growing season to make the plant attractive. What you need to do to ensure it remains neat is training.

Pests & Diseases

One of the things you will like about Dioscorea Mexicana is that it is pretty hardy. Its only disease is root rot which you can manage by keeping the soil dry. It also isn’t susceptible to pest attacks so you can rest on this count. You may rarely find and attack spider mites by applying the succulents’ pest soap to cure them.