Can this be saved?

[fanaticactus]

While repotting all my cacti with old, compacted soil into my new pumice mix, I found that probably the reason why this P. warasii (I think) is not doing well is that the whole underground portion of the stem had basically rotted. Starting from the bottom, the roots actually look fine. Then there's the section where the single interior brown stem is visible; I had taken away all the soft, rotted surrounding area. The trouble is, the brown fibrous stem itself is spongy. But the old gray area feels OK (I'll test it again, though), and certainly the new fresh green of the main upper body looks very good. Because of the sponginess of the stem immediately above the roots, should I cut away until I reach the firm part of the body (and dispose of all those great roots) and try to reroot the top? I've never tried to reroot such a substantially large cactus and just aren't sure if it's possible or how long it would take.

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[greenknight]

Yep, you have to cut off all the rot and re-root it. If you're lucky, that is - sometimes the rot has gone up the core farther than it looks like, and by the time you cut it all off there's not enough left to make a viable cutting. When you find something like that you should cut it off right away to have the best chance of saving the plant.

[fanaticactus]

What would be the best medium for attempting rerooting--pure pumice, gravel, sharp sand, DE (such as Napa 8822, Oil-Dri, etc.) or a mixture of some of them?

[Steve Johnson]

What would be the best medium for attempting rerooting--pure pumice, gravel, sharp sand, DE (such as Napa 8822, Oil-Dri, etc.) or a mixture of some of them?

Doesn't matter. If anything might stimulate new roots, it'll be a rooting hormone, not what you have in the mix. I believe the following might be helpful, and check out hegar's comments:

http://www.cactiguide.com/forum/viewtop ... 5&p=247858" onclick="window.open(this.href);return false;

Really sucks to see such a well-grown plant end up with rot, doesn't it? I'll think good thoughts for you on saving that beautiful Parodia!

[fanaticactus]

Steve, I'll most likely use Rootone before setting the calloused cutting on my mix. Since it's a much larger area than I'm used to dealing with, should I even go so far as to apply the powder evenly with a 1" paintbrush? Then, should I let the Rootone do its thing for a day or two BEFORE setting it into the mixture. I see in the link there is some difference of opinion whether to water lightly or not. I tend to agree with the majority I've read saying NOT to water. Sound good? Thx.

[Steve Johnson]

Steve, I'll most likely use Rootone before setting the calloused cutting on my mix. Since it's a much larger area than I'm used to dealing with, should I even go so far as to apply the powder evenly with a 1" paintbrush? Then, should I let the Rootone do its thing for a day or two BEFORE setting it into the mixture. I see in the link there is some difference of opinion whether to water lightly or not. I tend to agree with the majority I've read saying NOT to water. Sound good? Thx.

I would definitely recommend covering the entire cut area with Rootone before it callouses. Proper callousing is going to take more than a day or two before you should be ready to pot the plant. You mentioned that you live in a fairly humid climate, so I think we're talking about a few weeks (maybe longer?). Just keep an eye on the cut -- when it's dry and hard to the touch, you can repot. Cuttings should not be given any water unless and until new roots start coming in. Contrary to what some people claim, I don't believe that moisture in the mix does anything to encourage new roots -- IMO the only thing it'll encourage is risking the possibility of rot long before the plant ever has a chance to root.

[fanaticactus]

And the potted cutting should be placed in a warm (but not hot), light but shaded area? This whole process will probably take me into early winter at the earliest, right?

[Saxicola]

Don't go crazy with the Rootone. It should be just a light dusting over the cut stem. It will actually inhibit root formation if applied in too thick a concentration.

[Steve Johnson]

And the potted cutting should be placed in a warm (but not hot), light but shaded area? This whole process will probably take me into early winter at the earliest, right?

Yes, definitely shaded and not too hot. I don't know enough about Parodias to give you an ETA on the appearance of new roots, but all I can say is be patient. Unless you had to do a lot of cutting, there should be enough healthy tissue mass in your warasii to keep it going for new root development next year. But if you see new roots before the growing season is done? Bonus! I'll keep thinking more good thoughts for you.

By the way, good catch from Saxi on the Rootone -- follow what he says.

[fanaticactus]

Thank you both. With fingers crossed, I'll start this process tomorrow.

[fanaticactus]

Should Rootone be applied to the fresh cut directly on the moisture or wait until it dries a bit--maybe 12 hours or so?

[fanaticactus]

This is the final cut I've made. I know there's still a darker coloring in the center but I'm thinking it's the core of an old cactus and has taken on a darker color from its function of carrying moisture and nutrients to the healthy part. It does not seem soft like rot should be. And it clearly shows a sharp definition of the inner stem structure. Should I keep cutting anyway until the color disappears? Since I don't know how far it might go, I'm afraid there won't be anything left of the healthy remainder of the body. I've cut approximately 1/2-1" into the part that's green in the above pictures.

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[Steve Johnson]

This is the final cut I've made. I know there's still a darker coloring in the center but I'm thinking it's the core of an old cactus and has taken on a darker color from its function of carrying moisture and nutrients to the healthy part. It does not seem soft like rot should be. And it clearly shows a sharp definition of the inner stem structure. Should I keep cutting anyway until the color disappears? Since I don't know how far it might go, I'm afraid there won't be anything left of the healthy remainder of the body. I've cut approximately 1/2-1" into the part that's green in the above pictures.

Looks healthy to me. But then again, I haven't done surgery that deep into a cactus in a very long time, so I'd hesitate to say yes for absolutely sure. Hopefully someone else on the forum can confirm. Re. your Rootone question, dust it over the cut area while it's fresh. Powder adhering to the moisture in exposed tissues should provide maximum effectiveness of the active ingredients.

[Robb]

The cactus seems fine, I wouldn't want to risk cutting it any further though.

[fanaticactus]

Thank you, Steve and Rob. With that info, it's gonna be a waiting game. So this is probably the last post I'll have to make on this thread.