The myth that any plant does better when root bound is one of those urban (or should we say horticultural?) legends that, unfortunately, just refuses to die.

Urban legend with a grain of truth? A root bound plant is going to drain quickly-for those who over water, it might be a good thing for the plant.

Sugi, excellent and apt analogy.

Josh

Orchids and African violets do like to be snug in their pots, and typically will not flower if there's room in the pot to fill with roots. But that doesn't necessarily mean they prefer to be root bound, which often leads to damage. An unhappy root system is never going to serve your plant well.

What Sugi said holds true for many, many succulents. Most likely, you can listen to her advice forever and never run into a problem with many common succulent genera. However, for many of the prized species and rarer plants, this isn't always the case. Many Pachypodiums grow in a root bound state in nature, as they grow in small rocky crevices. Same goes for many Adeniums, Blossfeldia, Conophytum, Dorstenia, Aloe, Caralluma, Euphorbia, etc. Typically, these crevices provide ideal germination microenvironments for seeds and maturation environments for seedling, and also stay relatively moist compared to the hard surrounding desert or scrubland. Many of these plants have evolved root systems that deal with this problem (thickened roots of Pachys) or water-loss survival strategies that negate specialized roots (Blossfeldia). These plants are known as saxicolous plants and many of them appreciate at least some degree of root restriction to grow best. The best advice I can give is to ID your plant by its extended binomial nomenclature, and research it's habitat. Does it like root binding? Cold nights? Dry winters? High wind exposure? Getting some of these things similar may change how well your plant grows. For instance, many cacti (and Pachypodium brevicaule) require a cool to cold winter rest to flower well. They may still flower without it, but it's not the same.

For the plants you have mentioned, Graptopetalum paraguayense is endemic to a single mountain in Tamaulipas, Mexico and form part of the endemic xeric scrub there. This was only recently discovered despite the species' longtime cultivation, so info on natural growth is scarce/nonexistent yet. Both the other plants you mentioned have much less specific habitat needs, and both are found in dry scrub to rocky hillsides in South Africa, so I wouldn't root bind any of them since they don't exclusively inhabit such habitats in nature.

Thanks for the excellent information, Ben. It just goes to show, every plant has different requirements, and there are exceptions to every rule.. And I do believe replicating the plant's natural habitat even when grown in a container is a good growing practice, though I received some flack for saying so in the past.

Christopher

I have read that pachypodium saundersii will be triggered to increase caudex size in response to being root-bound, thus storing more water for dry spells. Conversely they grow more leggy in a root space that is larger. Is one growth pattern more healthy than another? Perhaps it is an adaptation to tolerate an adverse environment without ever being ideal?

ez

So...I should not have up potted my Pachypodium lamerei to an 8 inch unglazed Terra cotta from a 6 inch nursery pot? It's outside and getting a good bit of sun, I don't want my neglect to lead to it running out of water in a tiny 6 inch Terra cotta! I'm not sure if the roots would even fit. If I post a picture, would you be able to advise? I've also been thinking about placing the pot within another pot to protect it from the baking sun. It's protected from the evening sun but gets morning sun til about 1?

Of the pachy's, saundersii is said to be among the easiest to grow and that's all I have, so I'm a novice with the easy-peasy stuff and wouldn't presume to know lamerei.

ez

This is a pretty good source for Pachy culture info:

https://www.highlandsucculents.com/culture/highland%20pachypodium%20culture%20guide.pdf

Pachys should rarely be potted up, only when their roots are quite large. This ensures a more natural-looking compact form. Otherwise, they can easily etiolate, which weakens the plant and makes it more susceptible for rot.

Thanks, Ben!

hoovb zone 9 sunset 23

Urban legend with a grain of truth? A root bound plant is going to drain quickly-for those who over water, it might be a good thing for the plant

Now that, Gail, I would agree with. However, that is still not a matter of what the plant prefers but rather a way to offset a person's incorrect use of media and or watering.

dannie317(7, NYC)

Orchids and African violets do like to be snug in their pots, and typically will not flower if there's room in the pot to fill with roots

I would have to disagree, Dannie. I have many an orchid that is by no means root bound and still has plenty of room in its pot that bloom regularly. By the same token, I have grown AVs in terraria -- 55 gal and 90gal tanks. They were/are planted directly in the media and, again, bloom regularly and prolifically.

I do not know that I can concede completely to your point, Ben. Saxicolous may be adapted to grow in areas which will eventually wind up restricting the roots -- does that mean they truly prefer it/grow better that way? Or does is it simply indicative of their having adapted to grow in a niche that most other plants could not survive/compete? Twould be interesting to see studies on the matter. I wonder how much, if any, in depth work has been done on the topic with regard to such plants?

IMO those two things mean the same thing. Adapting to live in a given niche is the same as learning to prefer that niche. Some plants are obligate saxicolous species and can only grow "properly" on rock surface and in crevices (obligate saxicoles). Some plants are more generalist, and can occupy both rock crevice niches and deeper soils (facultative saxicoles). As in all parts of biology, saxicolous niche specificity exists on a spectrum. However, these plants are some of the least studied in the world, especially saxicolous cremnophytes since their habitats are so inaccessible. So they are not as well known as many other plant groups.

But "proper" growth in this sense really just means growth with a similar phenotype to that found in nature. Many saxicolous plants can be grown out of their niche, but they don't look the same. Some are thinner and taller (Pachypodium and some Mammilaria species), some are much larger, etc. Many of them are very rot prone in pot culture (Blossfeldia, Dorstenia gigas, etc) if not given other necessary components of their niche (like low air humidity, high temperatures, or water restriction) or small pots that mimic their saxicolous niche. This is especially true for many miniature montane cacti, which are mostly seen grafted in cultivation.

In short, yes, some saxicoles don't need their niche as they are more generalized. They can be grown in normal succulebt pot culture, and can be repotted like other plants. However, these and other less general species will look very unnatural when compared to the phenotype of wild grown plants if not grown hard as in nature, and if the conditions are too wet or too conducive to quick growth, the plants can eventually weaken and die, especially from rot.