Edithcolia grandis - growing conditions

[Melt In The Sun]

Well, I've killed two of these in 2011 and my third one is starting to look a little unhappy. I've tried lots of sun, little sun, little water, lots of water, and I can't seem to keep them from rotting at the base (and no cuttings will root, to add insult to injury).

Anybody got any cultivation tips?


photo from wikipedia

[cactusmcharris]

MITS,

You didn't mention heat in your message - has it been kept warm / hot? I had to make sure mine was warm all of the time, even in San Diego, or it would do as yours had done. I suspect more of the cryptic succulent Ascleps don't want temps below 50F ever, and preferably never below 60F.

[Melt In The Sun]

Yep, I've got it inside at a southwest-facing window, so it's kept >65F at all times, and it probably hits 80 in the midday sun. That may be why this one has hung on as long as it has. It's starting to get purplish and wrinkled though, just like the others before they bit the dust. One of the others died in late summer in part shade, so it was certainly warm enough. The second casualty probably got a bit chilled.

I've started watering a bit more; perhaps that'll help. I had been watering every 2 weeks or so. Maybe it wants to be treated like an adenium, with lots of sun and water?

[Duke]

Edithcolea grandis grows in Tanzania and adjacent Kenya right along the equator. As was stated above, they're not fond of cold temperatures, but they're also not accustomed to winter rainfall. The combination of these two factors should give you more success. I'm now growing at least a hundred of these from seed collected near Maji Moto Hot Springs, Tanzania, in July, 2010.

[Melt In The Sun]

Duke, do you know approximately what the summer and winter temps are in that area?

[Duke]

The temperatures in nearby Arusha range from 49 to 85 throughout the year. The area is somewhat tropical. Copied from the Web:
Maji Moto has a humid (> 0.65 p/pet) climate. The land area is not cultivated, most of the natural vegetation is still intact. The landscape is mostly covered with mosaic vegetation/croplands. The climate is classified as a tropical savanna (winter dry season), , with a subtropical moist forest biozone . The soil in the area is high in gleysols, histosols, fluvisols (gl), waterlogged soils with poor drainage and anaerobic conditions

[Melt In The Sun]

Sounds difficult to imitate. Three strikes and I'm giving up!

[Duke]

Give up if you wish, but I think you'll have success if you hold off on watering - with the exception of some misting to keep the humidity up - during the winter, and provide a warm spot throughout the year. In the following four photos you can see how big they can get under the correct conditions. The last photo is that of Maji Moto Hot Springs where they were growing in abundance. This should give you some idea of the humidity. The E. grandis were growing out in the open… no shade whatsoever, so drying out in the sun was undoubtedly rapid. Again, very little if any winter rainfall.

[Duke]

BTW,
All plants of this ilk are now in the family Apocynaceae, subfamily asclepiadoideae.

[cactusmcharris]

Further to what Duke elaborately added (thanks, Duke, I hadn't seen it in habitat), the fact that it's inside leads me to think that's another thing to make it unhappy. I haven't yet grown succulent non-caudex Staps up here in la belle Canada (I don't have the space - really!) but it will be the last Family I get into - too much hassle, but what a great group of plants, flower-wise.

[Melt In The Sun]

Thanks for the help Duke! Misting it is. Habitat shots help immensely; it's obviously not supposed to stay green!

I'm keeping it inside just for the winter, since that's the only way I can keep it warm enough. Humidity is a bit higher inside, so that would seem to help as well. It really does get a lot of sun, it's not just stuck in a corner somewhere.

[Duke]

I should have mentioned the purplish tone to healthy plants. Hang in there! Tucson is the perfect climate for lots of plants that are nearly impossible to grow elsewhere, but your conditions are right at the edge of a survival window. If the solar intensity or heat increased much, nothing would grow. Imagine someone on the equator attempting to grow saguaros. I sincerely believe that's why we grow a lot of what we grow. if it was easy or if anyone could do it, why bother?

[Tim Harvey]

I'm not so sure those plants wouldn't have a little shade from the shrubs and/or annuals they were growing under, during the summer. The pictures were taken in the middle of winter/dry season, and the available cover is likely to be somewhat different when water is available.

T

[Duke]

I am quite certain that these plants are growing in full exposure to the sun. The associative vegetation was mostly perennial; ergo, no major lengthening or expansion of plant material. There were some grasses in the area, but none were very tall and there were no signs of veld fires, burned remains, or charring on associative vegetation. There may have been an occasional clump of Edithcolea grandis near a bush, and that (those) plant(s) may have received some protection from the sun; nevertheless, the majority of large clumps were out in exposed conditions.