Pandas, yo.

Climate for one. At least where I’m at its too cold for bamboo to grow. Even in peak summer it’ll try to spread but its only a matter of time till the frost destroy it.

Now kudzu on the other hand. That shit is fucking up everything.

It is the same as other easily spreading plants. In their native habitats there are checks like diseases and predators. When you move them out of those habitats they can thrive at a new level because of the lack of those things.

I think an important thing to understand when talking about plant populations is to understand how they compete against each other. all kind of understand how animals compete because its dramatic with claws, fangs, speed and eating. They also compete more subtle with birthing rates, eating all the food faster than others but they are behaviors we can see. Each animal has it own ecological niche which they thrive

Since plants cannot move (mostly true) they compete against animals and other plants in other ways. They use chemicals to poison others, alter the soil for their own needs or attempt to shade out other plants. They also compete in a different timescale than animals. They may only grow for a few months of the year before anything else grows or have a super short reproductive cycle and flower multiple times per year or play the long game and invest into woody structure to grow taller and live longer than other plants. These are their own niches which include everything about temperature (both highs, lows, days at certain temperatures etc.), soil conditions, nearby plants, animals to help or hurt them and timeframes. These are plant’s niches. This means a plant community is never static. It is driven by a process called Ecological Succession

The things about garden and yards is that we don’t have a stable or natural ecosystem which means they are more unstable. We artificially keep it in a early stage of succession with mowing, fertilizers and pulling of weeds. This leaves plenty of open niches for things like bamboo to exploit. That is why pulling or poisoning of weeds just keep coming back since nothing is there to stop it from filling that niche again. So something like bamboo is almost impossible to remove without something else to outcompetes it in its niche. If we did nothing the bamboo would likely take over most of the grass and garden but eventually (in timeframes of years or decades) something else would eventually take it over or others would fill in around it. Usually plants growing creates additional niches alongside it. The succession would take over and alter the ecosystem.

This means that for something like bamboo we should attempt to control it in our garden setting with rhimozone barriers so it doesn’t run wild. Having things like native perennials or other perennials around it should outcompete any newer sprouts can help as well. Moreover, if you have weeds in your garden they will always be there unless you have something else already there. Any bare soil is just open ground for volunteer plants (a.k.a weeds) to take over to fill the empty niche. So to remove something you might not want you need to both pull it and have something else to replace it.

Bamboo is kind of a tree in this case which is an area I know more about and I think many of these factors would apply to bamboo as well. First forests used to actually be more rare than today before humans came along. Europe and North America was covered by endless plains which were grazed by huge numbers of ruminant animals. Any tree that would try to grow would get grazed before it could grow so tall that the animals couldn’t eat it anymore. That’s why grass thrives in such an environment, it’s practically made to get grazed. Once cut it quickly grows back again. Once ancient humans came along and hunted most of the grazing animals extinct forest suddenly started spreading like crazy until almost the entirety of Europe was forested (which was then to a large extent deforested again after agriculture was invented). Grass simply can’t compete against trees for sunlight. Therefore I would expect less or none bamboo in areas with a huge grazing wild life populations. And I don’t mean animals that would eat the leaves, but the ones that would eat the new seedling.

Another thing that limits trees is moisture. In general the drier the climate the less beneficial it is to be a tree. That’s because deep roots are of no benefit in dry climates (but they are of huge benefit in humid climates during drought). Grass which generally have very shallow roots suck up all the rain before it can penetrate deep into the soil while deep tree roots never get any significant amount of water. Trees handle drought well but constant dryness is very detrimental for them. Dry areas also tend to have wild fires which also hamper trees. It’s simply better to be a grass (if moderately dry) or a cactus like plant if it’s extremely dry.

Another factor is soil conditions. Now I don’t know what soil bamboo prefers but I doubt it’s all soil. Soil can have huge impacts on things like pH and water availability. For example in far Northern Europe where I live you can tell that you are standing on sandy soil if all around you are spruces and pines. If you however see lots of leaf trees you are probably on a silt and clay soil. This is because conifers handle both dry and sour soil better than the local leaf trees which leads to more conifers on sand. Bamboo is probably also limited to a certain soil condition.

I hope that can at least help you develop more theories on why bamboo is not everywhere. Something important to remember is that just because a plant can grow well in a certain location doesn’t mean it will be found there. That’s because plants are always in fierce competition. I bet bamboo if intentionally planted and cared for could thrive in lots more places than its found naturally, but it just happens to not be the best plant in that location, meaning it’s outcompeted over long time scales.