More Pachypodium (Six on Saturday #36, October 20, 2018)

Here are some more plants on their way to my greenhouse for the winter.  I previously photographed some of my Pachypodium plants and gave cultural suggestions in Six on Saturday #3.  Those photos, taken in July of last year, showed leafy plants.  Here in October, most of my pachypodiums have already shed their leaves and are dormant.  Flower buds will start to emerge in late winter to early spring, and fresh new leaves will follow.

All of the species shown here are from Madagascar

1. Pachypodium eburneum

Pachypodium eburneum is a very compact species with strongly compressed branches and relatively short inflorescences.  In that sense, it is somewhat like a less extreme version of P. brevicaule.  While P. brevicaule has soft spines, however, the thick spines of P. eburneum are hard and sharp.  Very old P. eburneum have a lumpy, irregular form, but this plant (eleven years old, grown from seed) is still nicely symmetrical.  The flowers of P. eburneum are white or pale yellow.

an old picture showing variation in the color of P. eburneum flowers

2. Pachypodium rosulatum var. gracilius

Pachypodium rosulatum is a very variable species that some botanists (and many horticulturalists) split into a complex of several closely related species.  Here, I’ll follow Dylan Burge [1] in considering this and the following plants to be variants of one species.

P. rosulatum gracilus is distinguished by its dense, very fine spines.  It generally has a bottle-shaped or globular trunk.  Flowers are small and bright yellow.  This is a seventeen-year old plant, grown from seed.

3. Pachypodium rosulatum (near Tôlanaro)

This P. rosulatum variant, which appears to be undescribed, supposedly comes from the vicinity of Tôlanaro (Ft. Dauphin) in southern Madagascar.  It has large yellow flowers and very sharp spines that are stronger than those of var. gracilius.  This plant was purchased as a small artificially propagated seedling in 2008.

4. Pachypodium rosulatum var. makayense

Like Pachypodum rosulatum var. bicolor, P. rosulatum var. makayense has bicolored yellow and white flowers.   At least under greenhouse conditions, var. makayense seems to be more compact than var. bicolor.  It is also more difficult to grow, and I have lost a number of seedlings to root rot.  This plant is eleven years old, grown from seed.

5. Pachypodium rosulatum var. cactipes

Pachypodium rosulatum var cactipes has fine, acicular spines, rather like those of var. gracilus, but in var. cactipes they are more widely spaced on long branches.  The plant shown above was purchased as a small seedling from Arid Lands in 1999.  It has the longest flowering season of any of my pachypodiums, producing yellow flowers successively over more than a month in mid to late spring.

Greenish lichens have started to grow on this P. rosulatum var. cactipes and some of my other pachypodiums.

The plant shown below also seems to be var. cactipes.  It is the “super branching form” sold for many year by Highland Succulents in Ohio.  I bought this plant in 2000.

6. Pachypodium windsorii

Pachypodum windsorii has bright red flowers in the spring.  The plant above, a 1997 purchase from Glasshouse Works nursery, is the parent of the seedling below.  Shortly after germination, I deliberately damaged the apical meristem of this seedling, and it responded by branching.  Usually pachypodiums branch after flowering for the first time, and the trunk is expanded only below the first branch.  In this seedling, each of the four basal branches is developing a swollen base, giving it the appearance of four plants fused together.  I think it will make a really nice specimen in ten or fifteen years.

An old picture of a P. windsorii flower

For more Six on Saturday, visit The Propagator.

Reference

1. Burge, D.O., (2013) Diversification of Pachypodium. Cactus and Succulent Journal 85: 250-258.