There's limestone all over England, but you won't find Bilberries growing on it (except perhaps on a thick layer of peat).
I haven't found cacti from west of the Andes to be very tolerant of alkaline conditions. Maybe there are some, and probably there are other calciphile succulents, but I haven't seen them.
There are certainly South American (and Caribbean) cacti that grow on limestone, although nothing like Mexico where it is almost a given. But few if any from the Andes westward. There is some limestone in Chile and Peru but the Andes are largely igneous and so are most cactus habitats over there. Maybe someone else can think of a cactus from there that likes limestone?
Just because a cactus grew in limestone does not mean they need limestone in the mix to grow, in fact some studies I came across indicated that limestone was an inhibitor to the growth and they did better without them.
FaeLLe wrote:Just because a cactus grew in limestone does not mean they need limestone in the mix to grow, in fact some studies I came across indicated that limestone was an inhibitor to the growth and they did better without them.
And if all other plant species do even poorer on limestone, even though they do not thrive it sure beats the competition in (on?) that niche.
Pretty sure that in Mexico, at least, it is the limestone areas that are the richest of all? The Huasteca Canyon just south of Monterrey and environs is incredibly diverse for cacti and succulents.
FaeLLe wrote:Just because a cactus grew in limestone does not mean they need limestone in the mix to grow, in fact some studies I came across indicated that limestone was an inhibitor to the growth and they did better without them.
And if all other plant species do even poorer on limestone, even though they do not thrive it sure beats the competition in (on?) that niche.
Not all plant species do poorly on limestone. Some thrive on it, and on other substrates. Some are obligate calciphiles and don't grow anywhere else. Same for strongly acid soils. The "they only grow there because nothing else does" argument has been thoroughly discredited but continues to raise its head The trick is working out which plants need limestone, which ones like it, and which ones just tolerate it.
Limestone does have the advantage for succulents that it is usually well-drained, often extremely well-drained. Impediments to growth are also rarely a problem for cacti, which are limited mostly by their own design. Once you overcome the basic problem of extracting locked-up nutrients then limestone soils are a walk in the park
Marlon Machado claimed cacti growing on limestone only grew when they received acid rain and as soon as the substrata turned the water alkaline stopped growing.
The trick is working out which plants need limestone, which ones like it, and which ones just tolerate it.
