Pachypodium & Caudiciforms ... 2/4

Caudiciforms

Caudiciforms (also called "Fat Plants") is a term for a non-botanically related collection of families of perennial plants.

In caudiciforms the stem and/or the root system has become swollen, so that food and water are stored in these swollen area/s, ready for a dry period hence enabling the survival of the plant when conditions are tough. Some caudexes can be deep in the ground, others are partly exposed, while still others are fully exposed to the air. They are not bulbs.

They are found in the lily, cactus, yam (here the caudex is a food), milkweed (Asclepiadaceae), convulvus (morning glory), primrose, cucumber (lots of caudiciforms), geranium, passion-flower, spurge (Euphorbiaceae) and grape families plus many other families.
They range in size from tiny plants, to the Australian and African Bottle Trees which are up to 3m wide.
Most caudiciform plants grown in collections are found naturally on the Africa continent and associated islands.
Here is a list of caudiciforms by family and genera courtesy of the fat plants web site.

Cultivation

Because Caudiciforms are found in so many completely unrelated families, it is not possible to have a "one size fits all" cultivation notes.
The cultivation conditions (water, soil, light, dormancy, temperature) that causes one plant species/genus to grow and even thrive, may cause another to sulk, or even kill another species/genus.
Knowing when your plant is dormant (in habitat) will help you decide what watering and temperature is right for the species at different times of the year, most are summer growing/winter dormant, but unfortunately there are exceptions to this - it all depends on the area of habitat eg dry summers/wet winters or wet summers/dry winters and the temperature range through the seasons. You cannot however exactly replicate natural conditions in your home - and you shouldn't either, so some concessions may have to be made.
Some caudiciform plants lose their leaves (and branches) when they dry out in dormancy, leaving only the caudex and the root system. This reduces evaporation and water loss as the plant goes into shutdown or hibernation, ready to spring into life when water is available again.

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