CactiGuide.com

I am a newby to cacti. I want to know more than what is on this site about Pilosocereus Purpureus. How should I care for it, cultivate seeds, how big does it get, how to prune it, dormancy, watering it, etc. What climate does it come from?. We are in zone 6. Any info will be appreciated.
Bettyg51

That species doesn't exist, what's being sold under that name is most likely Pilosocereus pachycladus. Not a difficult species, but it's from Brazil so not cold-hardy. For details, see - http://www.llifle.com/Encyclopedia/CACT ... achycladus

http://cactiguide.com/cactus/?genus=Pil ... s=purpusii has information on this species, but the photo does not match exactly. The one I have is a single column with two wooly beard-like patches of hair. The label says it grows in Mexico. I should have spelled it as pilosocereus purpureus. I misspelled it in the previous message.

You did spell it right in the body of your post. It could be P. purpusii, which is a less common species (and it is from Mexico), but I've seen what appeared to be the much more common P. pachycladus sold under the name P. purpureus. Could you post photos?

Care is about the same in either case. Those "wooly beard-like patches" are produced by all members of the genus - called a cephalium, it's a structure from which flowers grow. This site show a P. purpusii with a cephalium and flower - http://davesgarden.com/guides/pf/go/141068/

I am trying to attach a photo. The cactus is about 7 inches tall.

Interesting - they don't usually form a cephalium until they're quite large, an they're near the tip of the branches.Looks like a cutting taken from a big cactus that already had them.

Not enough detail in this photo for an ID. However. P. purpusii is supposed to have 12 ribs - how many does it have?

As for care, it should be dormant now - leave it dry until weather warms in the spring. It will need a bigger pot soon, pottng mix should be very gritty and free-draining. During the growing season give it as much sun as possible, let the soil dry deeply between waterings. Fertilize lightly with a low-nitrogen fertilizer. They are rather slow-growing, I doubt pruning will ever be an issue.

The problem can be with top cuts with lateral cephaliums often known as pseudocephaliums (a cephalium is strictly a terminal crowning structure, as in Melocactus where the plant body stops growing) is the pseudocephalium may stop growing and the plant revert to normal growth until it gets tall enough for a pseudocephalium to form again.

There were quite a few top cuts of Backebergia militaris imported into Europe in the 1960's. I knew a chap that bought one complete with cephalium and he was devastated when the normal stem grew through it again to try and reach its normal cephalium bearing height of around 30ft.

See:-

http://www.sbs.utexas.edu/mauseth/Resea ... phalia.htm

It has 11 ribs.
Thanks for the care instructions.
Betty