Ber a écrit :Dj Ferguson ?! Est-ce celui qui a inventé le tracteur disco-mobile sound-system ?
Tu rigoles mais C'est
LA référence de tout ce qui touche aux Opuntia et Agavacées et Echinocereinées et autres.
Il a une connaissance impressionnante de ces plantes et de leur habitat et a une analyse fine de toutes ces familles et de leur acclimatation.
Il est accessoirement le "Curator" du Rio Grance Botanic Garden au Nouveau Mexique vers Albuquerque Z7a.
On trouve souvent ces réf de collecte avec les initiales DJF.
Je vus mets son analyse de cet Agave montana (c'est un long, en anglais, mais vaut le détour)
Here is the bottom line. Agave montana does well in cold when conditions are moderately dry to dry and very sunny through the winter. It does not do well in climates with damp freezing winters. It is not quite as cold hardy as certain other species (even some that come from hotter climates). I hope you can find a way to succeed with it, because it is a very nice species. I suspect that if you try several plants from different locations, you will eventually find one that will work for you.
Just for the record, I have been growing and observing cacti and other succulents for about 40 years, and my observations are indeed based on direct observation, not theory (though theory always plays a part in learning - for you and for me).
A. montana will grow fine near the East Coast in the US in USDA Zone 7 (it is being grown in North Carolina with great success), but that seems to be about the limit (keeping in mind that such a designation only accounts for one of many factors of climate, and even some USDA Zone 7 areas may be "too cold and damp").
Indeed, not all species are created equally, and sometimes their responses may seem illogical when one takes into account their original habitats. However, there is more to the adaptations of plants than just where they are now growing. Each has a genetic inheritance that incorporates traits and adaptations that may affect how they respond to habitats other than those in which they are now found. The fact that A. montana has as it's closest relatives species of subtropical and tropical climates may well be an indicator that A. montana itself grows near the limits of its cold tolerance in habitat. On the other hand A. lechuguilla and others are perhaps of more northern affinities, and may be inherently much more cold hardy, even if they are now growing in hotter and drier climates naturally.
I should also add that while A. montana indeed does grow at high elevations (from roughly 4000 ft to 11000 ft), often in desert or grassland, but also often with conifers and oaks, it is not in such a cold climate as one might imagine. The trees in these woodlands, even above 9000 ft, are full of brommeliads, there are often Brahea palms in the understory, etc. The climate, even at 9000 ft, is quite mild. It is sunny and dry in the winter (but it can freeze at night, and it can snow occasionally). Even at this elevation, people have problems getting traditional fruits in the Rose Family such as peaches, cherries, and apples to produce fruit reliably, because there aren't enough hours of chilling. Though they do have some luck with them. It is a very different place from Virginia or Maryland (or for that matter from Denver or Albuquerque).
Another thing - Agave bracteosa grows fairly low down by comparison (I think about 4000 ft, but can't remember for certain), but it grows on steep (nearly vertical) slopes where it is shaded for part of the day. It does get cold (perhaps just as cold in the extreme as are most A. montana habitats, though probably not as cold on average). There are Agave montana growing very near to A. bracteosa (though I don't remember if they are actually together). Agave bracteosa often grows in close proximaty to Pinyon Pines, Oaks, and Junipers, and it is a habitat milder, cooler, and moister than much of the surrounding desert. On the flip side, it is hotter in summer, probably sunnier, and definitely with less rainfall than most A. montana habitats (it may not be drier though, due to the microhabitat in which it grows). Visiting A. bracteosa is fun, because it grows alongside a number of other interesting plants restricted to the same habitats.
A comment on A. havardiana. It is not a desert basin species. As the easternmost representative of the A. parryi complex, it is a plant of mountain slopes. It is usually found in grasslands or woodlands, and only occasionally enters the upper edges of the deserts (as in s. New Mexico and adjacent Texas, at the northern limits of its distribution). A. schottii is also a species found at and above the desert margin on mountain slopes. It is generally not found down in the desert basins. It is at least as often seen with Oaks and Manzanita as with Saguaros, but it is indeed from considerably hotter locations than are many of the more cold hardy species. In fact I've always considered A. schottii only marginally hardy in USDA Zone 7, but some clones seem much more cold hardy than most.
ouep j ai aussi des agaves en mutation vers un liquide precieux qu est la tequila 
parrasana americana scabra lophanta 
comment distiller svp 
Quezako ? 
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tripoter mes agaves 
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Tout est mou pour ainsi dire, même le coeur. 