Pachypodium Rutenbergianum is a species of Pachypodium originated from and native to Madagascar. It is a deciduous tree that can reach 3 to 12 m high, and it is relatively fast growing for a Pachypodium. It is probably the largest also, easily attaining tree proportions. This tree is very nice in maturity.
The cigar shaped trunk can measure up to 60 cm at the base. It is a smooth silvery brown and the plant may reach 30 feet in time. The plant has short branches and small (1 cm) long, fat, conical spines.
The green leaves are long (10-20 cm), narrow (4 cm wide), and only grow at the very tips of the branches. They are oblong with pointed ends with a lighter green vein, running the length of the leaf, and dark red veins on the underside. The leaves form around the growth tips of the trunk and branches and have a downward curvature in the length.
The white and pale yellow flowers are very pretty and showy, about 30-45 mm long and 12-15 mm wide and they bloom in mid winter. The flowers are large white salver form with a yellow center and the smell of perfume. The fruits are reddish brown and oblong, about 30 cm long and 4 cm wide, and they always grow in pairs.
Two significant adaptations allow Pachypodium to survive in dry, hostile environments: “pachycaul” trunks, and spines. The thick, more or less pithy, trunks of Pachypodium facilitate water storage similar to a cactus. The trunks and branches can also photosynthesize, making the leaves, which can cause rapid water evaporation from the plant, unnecessary in times of drought. Spines help condense moisture from fog or dew into drops which fall at the base of the plant.
Hardiness Zones: 10 – 11 (1c/35f, 4c/40f). In its native habitat Pachypodium Rutenbergianum grows mostly on rocks and sand dunes in dry habitats up to 400 m elevation. The Rutenbergianum should be given full light and plenty of water during the warmer months and less water in the cool months but should be dampened before drying out occurs. They rot easily in winter when it’s cold and they are wet for a long period. This species is one of the least widely cultivated of the tree species. The plant has spines or sharp edges; use extreme caution when handling.
The Pachypodium are robust succulents that rapidly respond to their growing environment and therefore require high light levels to keep them in check. A few hours of direct light each day and a minimum temperature of 55F will keep them happy. They will grow well indoors on a sunny window sill, outdoors during the warmer months, and in a greenhouse as both of these conditions are easily met. .