When I started writing this in mid-October, all the Pachypodiums in my greenhouse were still green. I expected the first yellow leaves in November, as in other years. A few days later they had already started. By October 17 the lower leaves on my older lamereis were turning yellow, a few weeks earlier than I’m used to. The first time an older Pachypodium begins dropping leaves in autumn or winter, it’s hard not to worry that something is wrong. Most of the time nothing is, but sometimes it is, and I’ve lost a few plants that way.
I’m not a Pachypodium expert. I grow a few species, mostly lamerei, geayi and namaquanum, and I’ve had them through several unheated winters on my glazed balcony before moving everything into the greenhouse this year. This is what I’ve seen with them.
Seedlings vs. older plants: why only some Pachypodiums drop leaves in winter
If your Pachypodium is young, it will probably keep most of its leaves through winter. My own Pachypodium lamerei seedlings did, every year so far. They lost a few leaves in spring, when the new ones started coming in, and that was it. The same went for the two Pachypodium lamerei var. ramosum I bought at around four years old. Here are my lamerei seedlings over three winters on the balcony:
Older plants are different. They lose leaves slowly over the winter, a few at a time, starting with the lowest ones in the rosette. My Pachypodium geayi, which was already eight or nine years old when I bought it around 2022, loses the most. By the end of winter it has dropped around 80% of its long silver leaves. My old P. lamerei loses less, maybe 40–50%, and keeps a fuller rosette at the top. In spring both grow new leaves from the top, and over the season the old leaves are gradually replaced by new ones.
This is what they looked like on October 17. On all the older plants it's the lowest leaves that turn yellow first, while the new leaves at the top stay green. The lamereis started earlier and are yellowing faster than the geayi, but they usually keep more of their upper leaves through winter. My old geayi starts later and ends up losing more. My young geayi seedlings don't lose many leaves at all, but in many species seedlings behave differently in their first years.
So an older plant losing leaves gradually in winter, with leaves yellowing from the bottom up, is normal. To check whether something is actually wrong, I look at the stem rather than the leaves.
Pachypodium namaquanum: leaf drop in summer instead of winter
Namaquanum works the other way around. Mine is about 11–12 years old, and I’ve had it for four or five years. It drops its crinkled grey leaves at the end of spring, stays bare through the hot months, and grows new leaves at the end of summer. So if your namaquanum loses its leaves in June or July, that’s its normal rest, not a problem. I’ll write a separate post about how I grow it next month.
My namaquanum seedling, now three years old, has kept its leaves all year so far.
How to tell dormancy from rot: squeeze the stem
When one of my Pachypodiums drops leaves, I gently squeeze the stem between the spines. If it’s firm all the way down to the soil, the plant is fine and just resting. If it feels soft anywhere, especially near the base, that’s rot.
This is how I lost one of my namaquanum seedlings. I had two of the same age, and both got through their first winter on the balcony without problems. In their second winter, one of them died. That winter wasn’t even colder; the balcony stayed at 5–6°C (41–43°F) or above. There were more humid days, though, and even with the seedlings kept dry, it wasn’t enough. I only found it in March. The base was soft and looked odd near the soil, but the top of the plant still looked almost normal, so I hadn’t noticed anything earlier.
My earlier Pachypodium losses happened faster. P. cactipes, P. horombense and one baronii (or windsorii, I’m still not sure which) all died during their first winter with me, before spring came. Looking back at all of them, I think the problem was humidity together with cold. Cold on its own, with dry air, my plants handled much better. I wrote more about this in my post on minimum winter temperatures for caudex plants and cacti.
Soil makes a big difference here too, because a mix that stays wet for days in cold weather is exactly what leads to rot. My big P. geayi is in a mix that’s about 80–85% mineral, my geayi seedlings are in about 70% mineral and 30% organic, and my P. namaquanum is in a fully mineral mix. I explained all my mixes in last week’s post on soil mixes for caudex plants.
Winter watering for Pachypodium
P. lamerei and P. geayi: I water very little in winter. Just enough now and then that the roots don’t dry out completely.
P. namaquanum: a bit more, around once every three weeks, and only on warmer days when the air is drier, so the pot dries out again quickly.
Seedlings: the same as the adult plants of their species, but they get the warmest spot.
When to start watering again in spring
I start watering again depending on the weather. If early March is warm, I start then. If it’s still cool, I wait until we get days of 20°C (68°F) and above. New leaves appearing at the top of the plant are a good sign that it’s ready.
What’s next
This is the first winter my plants will spend in the greenhouse instead of on the balcony. I’m setting the heater thermostat to 8°C (46°F), and I’ll keep an eye on humidity as well as temperature.
Next week’s post stays with these plants: how to tell Pachypodium geayi and P. lamerei apart, since they’re easy to mix up when they’re young. Later I’ll also write about my P. namaquanum and its mineral mix, and in spring about growing Pachypodium from seed.