The Pachypodiums are succulent plants such as the cactus, but the basic difference is that the Pachypodiums have visible leaves, in some species the leaves are even very large in relation to plant (For example Pachypodium rutenbergianum, Pachypodium lamerei).
This characteristic means that this plant use its leaves to acquire their necessary needs for water and carbon dioxide quickly. So they acquire their nutritional needs especially during the rainy season which may be suddenly and violently in the warm season. This is necessary for them as the growing season is quite short in their natural environment.
The Pachypodiums have large fibrous roots that absorb moisture very quickly as they need to take advantage of the sudden (but very rare) good rains in their natural habitat. In contrast, the majority of the other succulent plants has much finer roots.
The Pachypodiums have a thick and shiny bark that makes it possible for them to reflect the strong sunlight and to protect themselves from drying out during the long periods of drought.
Growing Conditions and General Care
The three parameters of light, temperature and watering are closely linked: you should not change one without the other two. It is therefore important to note that the balance of these three parameters determine the good or bad health of their plant.
All kinds of Pachypodiums – except perhaps Pachypodium succulentum and Pachypodium bispinosum from South Africa – need much light because they originally grow under full sun in tropical countries. Direct sunlight is not absolutely necessary, but the sunlight should not be shielded by a natural (or artificial) view protection. A Pachypodium with a lack of light will wither, its branches will be weak and appear “lean” and the leaves will be too big and soft. Over time the Pachypodium will be susceptible to disease and fungus and the plant will eventually die.
The temperature can be very high, as in the habitats in Madagascar and South Africa in the summer. The minimum temperature is much more impotant for growing Pachypodiums because it triggers the rest. For most types of Pachypodiums the minimum temperature is about 55° F (13° C), but it depends very much on the moisture of the substrate. The drier the substrate, the lower temperatures are possible. Ideally you shouldn’t fall below a minimum temperature of 59° F (15° C) during the rest period.
In the growth phase the Pachypodiums require a lot of water. The fact is that the climatic environment drives them to store as much water as possible in a short time. As the rainy season can be very short, the plant must quickly invest their reserves. Some people say they are opportunists. For beginners it is sometimes difficult to consider when and how much water you should give the Pachypodium. You should not treat it like a cactus in any case. A helpful rule is to not be completely dry to the soil during periods of growth before it is poured again.
The dormancy or rest period of Pachypodiums is the most delicate moment to decide if you should water or not and how much. It is the time that is most misunderstood by beginners. In fact, it is different from other succulents so that the plant is not likely to survive without irrigation until next spring. Although the plants are very hard plants, you should consider that the plants need regularly water to replenish its moisture reserves in the rest period.
Pests and Diseases
Fortunately, the Pachypodiums are very rarely attacked by insects and also fungis are scarce. It is always better to solve the problems that may occur in a mechanical way (such as spraying water on the leaves, when beetles are on) or to try biological and organic products. Most of the problems come from the treatment and the cultivation, so it is important to first think before treating the plant with an aggressive product, because the consequences for the plant could be very bad.
Source: seedsplants.com