Caudex Plant Dormancy Guide — From Leaf Drop to Spring Awakening

Many caudex plants shed their leaves in autumn and enter a period of dormancy called "hibernation" until spring. Managing this dormancy period is the most important aspect of caudex plant cultivation and also the most error-prone point. Misjudging watering during dormancy can lead to root rot and loss of valuable plants, so correct knowledge and experience are necessary.

What is Caudex Plant Dormancy?

Dormancy is a survival strategy where plants stop growing and minimize energy consumption in response to dropping temperatures and reduced daylight hours. It corresponds to the dry season in Madagascar and southern Africa, during which caudex plants survive the winter using water and nutrients stored in their root masses.

Caudex plants are broadly divided into "summer-active" and "winter-active" types, with different dormancy timings.

Summer-active (dormant in winter) This includes most species from the Pachypodium, Adenium, Operculicarya, and Euphorbia genera. In Japan, leaf drop typically begins around October, with the dormancy period running from November to March.

Winter-active (dormant in summer) This includes some species from the Tylecodon, Sarcocaulon, and Pelargonium genera. In Japan, leaf drop occurs around June, with the dormancy period running from July to September.

Don't Miss the Signs of Dormancy

The transition to dormancy happens gradually. Pay attention to the following signs.

Leaf drop begins Leaves begin to yellow and dry, falling off starting from the bottom. In Pachypodium, leaves turn yellow in autumn and drop one by one. This is not a disease but a natural transition to dormancy. There's no need to rush into increasing watering or bringing the plant indoors.

Water absorption slows down During the growth period, soil dries out in a few days, but after watering during dormancy, the soil stays moist for an extended time. This signals reduced root activity and is the time to increase the interval between waterings.

Growth stops New leaf development stops, and branch elongation ceases.

Watering Management During Dormancy

Watering during dormancy is the most debated topic in caudex plant care. There are two main schools of thought: the "complete water withdrawal" approach and the "minimal watering" approach, each with its own merits and risks.

Complete water withdrawal approach During dormancy, roots don't absorb water, so watering causes the soil to remain moist and increases the risk of root rot. Many breeders manage plants like Pachypodium gracilis with complete water withdrawal. The dormancy period spans approximately five months from November to March, during which no water is given at all.

Minimal watering approach Some believe that complete water withdrawal causes fine roots to die, delaying spring awakening. This method involves lightly misting around the base once a month or giving small amounts of water on cloudy days to prevent complete root death.

Recommendation for beginners "Nearly complete drought with minimal watering once a month" is recommended for beginners. On a warm, sunny morning, give about half a cup of water around the base so it dries quickly. During winter watering, less is safer, and if in doubt, it's lower risk not to water.

Winter Storage Location and Temperature Management

Temperature guidelines Summer-active caudex plants are safest when maintained at a minimum of 10°C during winter. Pachypodium and Adenium ideally prefer 15°C or higher, but plants under drought stress can tolerate temperatures as low as 8°C. However, considering safety margins, keep temperatures above 10°C.

Storage location A well-lit windowsill indoors is the basic choice. However, windowsills cool down significantly at night, so if the minimum temperature drops below 10°C, move the plant away from the window or wrap it with cardboard for insulation. A heated room is ideal, but avoid locations where heated air from air conditioning blows directly, as it causes excessive drying.

Using plant grow lights Even during dormancy, avoid completely dark spaces. If storing in a room without windows, use plant grow lights for 6-8 hours daily to provide minimal light.

Spring Awakening and Resuming Watering

As spring arrives, plants wake from dormancy and resume growth. The awakening timing varies by species and environment, but typically occurs from late March to April.

Signs of awakening Small buds begin to swell at branch tips. In Pachypodium, the appearance of green shoots at the branch tips signals awakening.

How to resume watering Once you confirm signs of awakening, gradually resume watering starting with small amounts. Begin with only about one cup of water, then over a week, confirm the soil dries before the next watering. Giving a large amount of water at once risks damaging roots weakened by dormancy. Over 2-3 weeks, gradually increase the amount and frequency of watering. Once multiple new leaves have developed, return to the normal watering cycle.

Caution Avoid starting watering before buds appear. Watering prematurely because it's warmer risks root rot in still-inactive roots. Always confirm signs of awakening before resuming watering.

Dormancy Troubles and Solutions

Caudex shriveling During dormancy, the caudex may become slightly soft or develop minor wrinkles, which is normal. This occurs as the plant consumes stored water, and the fullness returns once watering resumes in spring. However, if the caudex becomes extremely shriveled or mushy, suspect root rot.

Mold growth Storing in high-humidity locations with poor air circulation can cause mold to develop on the base or soil surface. Remove mold and move to a better-ventilated location.

Get Dormancy Management Advice from br-choku

At br-choku, you can purchase caudex plants from breeders with extensive management experience and receive specific advice on dormancy care. If you're tackling winter dormancy of caudex plants for the first time, try consulting with a breeder on br-choku.