Grafting large seedlings

[Shane]

I was grafting a ~9 mo old Astrophytum seedling to try to help it fight some rust (see this topic. My idea was it wasn't in critical danger right then, and grafting would help survive the infection in the long term

Anyway, I cut the seedling and didn't see anything that very clearly looked like the vascular ring

20191205_150115-472x472.jpg (44.94 KiB) Viewed 2987 times

The white dot in the middle is my best guess. Is that right?

I also realized maybe Pereskiopsis wasn't the best stock choice of a scion of that size. If indeed the vascular bundle is in the very middle, I'd have to graft it with half the scion hanging off the edge to get good ring overlap (which is what I did). Should I have used a different stock? If so, what?

I really don't think the graft is going to take which makes me really sad because that was my favorite Astro seedling

[Pereskiopsisdotcom]

The white dot in the middle is where the connection can be made. Keep in mind that successful grafts can also be made at the areoles. I have often cut problematic looking seedlings (larger) at a cross section that included at least one exposed (cut cross) of an areole. In that case the graft has an even higher chance of success.

Also, I forget where I read it but I've seen in practice that there are many vascular bundles and that the center one is only the main one. Other vascular connections can be made and maintained. However they are not as fast growing and will appear stagnant but survive. Occasionally, they'll shoot out substantial growth months or years later. Sometimes they appear to not grow at all ever. In any case, it's worth trying because even if you could make a successful connection with no growth you could still keep the seedling alive until a later point.

[Shane]

The white dot in the middle is where the connection can be made. Keep in mind that successful grafts can also be made at the areoles. I have often cut problematic looking seedlings (larger) at a cross section that included at least one exposed (cut cross) of an areole. In that case the graft has an even higher chance of success.

Also, I forget where I read it but I've seen in practice that there are many vascular bundles and that the center one is only the main one. Other vascular connections can be made and maintained. However they are not as fast growing and will appear stagnant but survive. Occasionally, they'll shoot out substantial growth months or years later. Sometimes they appear to not grow at all ever. In any case, it's worth trying because even if you could make a successful connection with no growth you could still keep the seedling alive until a later point.

Thanks, all that's very good to know. I hope my graft takes, but if not I hope it has enough vitality for a second try keeping what you shared in mind

[Shane]

An update:
The graft did not take. But it was still healthy enough for a second try about a week ago. I think it fused this time. I'm going to remove the p-film soon so I can apply fungicide, I'll know for sure then

A much neater graft than the first time

20191229_214907-616x821.jpg (50.73 KiB) Viewed 2674 times

You can see the fungus on the right side of the seedling. I'd resigned myself to losing this one, and I'm really happy it's hanging on for now

[TimN]

Hopefully things will work out. Nice to have some grafting practice.

[Shane]

The graft did take the second time. It hasn't done much since then

[Shane]

I have a minor update: though the stock lost its leaves to aphids, the scion has been growing and now is slightly bigger than its non grafted siblings

[Pereskiopsisdotcom]

I have a minor update: though the stock lost its leaves to aphids, the scion has been growing and now is slightly bigger than its non grafted siblings

I'm glad you're honest about that. Pereskiopsis is tough but too many people act like it's invincible, that it will never rot, or get attacked by insects or fungus. I see it first-hand myself. It's just much more tolerable than most cacti.

[Shane]

I'm glad you're honest about that. Pereskiopsis is tough but too many people act like it's invincible, that it will never rot, or get attacked by insects or fungus. I see it first-hand myself. It's just much more tolerable than most cacti.

Agreed. Though I would argue it's more susceptible to aphids because they really like to eat leaves. And it seems like its response to things it doesn't like is going into dormancy and not wanting to come out. Which is pretty annoying (to me), to say the least