Soil Mix for Caudex Plants

As the global trend in biophilia continues to evolve, many people have started to expand their botanic collections to include even more rare and unique plants with diverse and delicate care requirements. One group in particular that is getting more attention for its unique characteristics are Caudiciform or caudex plants. They are not a cactus, they are not a succulent, and they are very distinct in that they produce an above-ground root called a caudex. One variety you might know already is the ponytail palm. Another one you may not have heard of yet, which Zamzows has recently received in with our plants, is the Stephania Erecta caudex. Stephania plants look like a potato, but unlike a potato, they are found growing amid limestone in the humid jungles of Southeast Asia, namely, Thailand and Indonesia. Caudex species can be found all over East Asia and Australia though.

As with all plants, the caudex group won’t do well without the correct care. Their care starts with the soil's composition which will control moisture, nutrition, evaporation rate, and humidity. Because caudex plants have a woody exterior, they can be prone to rotting like cactus, so there is a mix that is ideal for caudex plants to help keep them happy.

It is a good rule of thumb to let most plants go through their water before you give them more. This is also very true of the care for caudex plants. Airing on the side of “less” is a good way to gauge how frequently you need to water. The trick with caudex plants is that they are prone to rotting, but they also need enough water to provide them with regular humidity from evaporation. If your caudex plant starts to lose any firmness and it becomes squishy, it is rotting. This is where soil mix is important. You want a mix that you can water more frequently, that will still have nutrition, but then will dry out quickly between waterings to provide humidity. If you are looking to get into this unique plant group, we recommend this easy soil mix below.

1 part coco coir or peat (Moisture Retention)

1 part pumice (Water Absorption)

1 part perlite (Aeration)

½ charcoal (Prevents Disease)

½ cactus soil (Similar to Habitat Medium)

½ Worm castings (Optional addition for fertilizer, usually already in cactus soil)

When planting a Stephania caudex it is important to remember that you don’t bury the tuber too deep. Identify the top and bottom so you don’t plant your Stephania upside down and then you will just busy the lower ½ inch of the caudex in your soil mix. 

Notable Caudex

Ponytail Palm, Stephania (Erecta, Cepheranthe, and Nova), Dioscorea Elephantipes, Desert Rose (Adenium), and Albuca Spiralis to name a few. 

CAUTION: Like many others, this plant is poisonous to animals if consumed, take care that it is in a safe place as it is a ball, and can chewed up easily.