The Nursery (Part 10: Off with their heads! 4 of 5)

This is the fourth part of the post on grafting cacti and will consider whether to keep a plant permanently grafted or alternatively attempt to degraft it.

Once you have a grafted plant you might consider whether to keep it that way or whether to try and do something drastic. If you’re content with your grafted plant, so much the better. However, many collectors find their appearance unattractive and wish to either hide the stock plant or do away with it altogether. Of course, if the purpose of the grafted plant is to produce shoots or seeds it isn’t very important how it looks.

If the stock is low enough, it is often possible to hide it completely in a layer of grit if you have a deep pot. Care must be taken that the grit is of a large enough grain size so as to hold as little moisture as possible. Burying a stock in material that retains moisture for prolonged periods is to invite rot. But this way it’s possible to make a grafted plant appear as if it’s growing on its own roots. If the stock is too tall to do this, it’s possible to cut it off a little below the scion and set it to root. Once it sets roots it can be potted and the stock buried in grit. Beware though, that if the stock is old it might not form new roots easily.

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Fig 15: Obregonia denegrii grafted on a very short stock that has been buried beneath grit. As can be seen, the Obregonia looks as if it grows on its own roots.

However, you might decide that you want to try and have the scion grow on its own roots. Sometimes the decision might be forced on you if e.g. the stock plant dies and you don’t have the option of grafting the scion on something else. Then it’s necessary to try and get the scion to form its own roots.

The practice of separating scion from stock is called degrafting. It isn’t any more difficult than taking a clean knife and cutting off the scion. At least, not in theory. It is certainly tempting to degraft when the scion has grown nice and big, though having the plant form its own roots can be tricky. Some species root only with great difficulty and may wither and dry up before putting out roots. Other species are more accommodating and will put out roots with ease. The scion should be cut off as far down as possible. If enough of the scion remains on the stock it is possible that it will put out shoots that can be removed at a later date. If the cut surface is very large compared to the size of the scion, it is quite likely that it won’t survive. The smaller the cut surface compared to the plant body, the greater the chances that it will survive. Some species might take months to put out roots, and during that time it’s vital that the plant has enough water reserves to last.

Many species are very reluctant to form roots and some species (like Ariocarpus) will never form a proper tuberous root after being degrafted. It is also fairly common to find that the roots formed by a degraft are not as strong as those formed normally by a plant.

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Fig 16: Various degrafted plants. Upper left is Glandulicactus wrightii, Epithelantha bokei, Astrophytum asterias cv. Super Kabuto and Astrophytum capricorne var. crassispinum cv. Taiho. All set root except the A. cv. Taiho. Upper right shows Sclerocactus cloveria ssp. brackei of which all set root. Notice the unusual pink colour of the flesh. The lower image shows Geohintonia mexicana and Echinocactus polycephalus ssp. xeranthemoides of which only one of the Geohintonias has set roots after about 4 months.

In Fig. 17 you can see the various plants I degrafted and then placed in a tray for rooting. They are sitting in a medium consisting of cat litter (this particular cat litter is made of a form of diatomaceous earth and doesn’t clump or change shape when wet), and perlite (the white stuff). The tray was placed on a shelf above my two lamps where they’d be out of direct light but receive a good deal of bottom heat. After a few weeks I started to moist the cat litter and perlite slightly. The cut surface of the degrafts were all treated with root stimulating hormones in powder format, although I am unsure whether this helped at all and it’s not something I feel is needed at all. About 60% of the plants formed roots within 1-2 months, while Geohintonia (of which only one of four formed roots) needed 3-4 months. The Echinocactus, Blossfeldia and some of the Pediocactus failed to form roots.

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Fig 17: Degrafted plants in a tray ready to form roots..

If you really want to degraft a scion, but are worried that it might not survive the process, it’s possible to cut off the top of the scion and either discard it or regraft it (or even just destroy the growing point). The remaining part of it will soon put out new shoots (even if it wouldn’t normally do so), that might in a few months’ time be easy to cut off with only a minimal wound and then set to root. All the while the old scion could continue producing new shoots for you.

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Fig 18: Pediocactus peeblesianus ssp. fickeisenii sprouting profusely after having its head removed for rooting. The cut off head never formed roots, but as can be seen there are plenty of future prospects here for rooting in a few months’ time.

 

A change of scenery

Previously this blog was hosted by Blogger, but I decided it was time for a change. The old address (www.living-rocks.blogspot.com) will no longer be used. I couldn’t keep the old title of the blog as that particular domain name was already taken. Therefore I had to come up with a new name. I am quite happy with the name and site change and hope it will spur me on to more frequent updates!

-Karl

Update

It’s been a long time now since my last post. My apologies to those of you who have been stopping by over the past few months hoping for updates! I will try to publish more often in the future, and start with a pictorial update of some more flowering over the past few months. All the plants shown below are between 16-20 months old at the time the pictures were taken.

First off, my Pseudolithos cubiformis and P. mccoyi have simply not stopped flowering over the past year. Whenever one plant has begun flowering another has set buds, and so on. Thankfully the smell (or stench) of rotten meat from the flowers isn’t very noticeable unless you get your nose up close to them. I still haven’t been able to pollinate any of the flowers, but with summer now arrived I hope that some flies might come along and help out.

Pseudolithos cubiformis with a bunch of buds ready to open.

P. cubiformis with the flowers just starting to open. 

P. cubiformis with all the flowers open. They stay open for about two days.

Two P. cubiformis in flower. Unfortunately I don’t know how to pollinate them without the help of flies.

Pseudolithos mccoyi in flower. The flowers are quite a lot smaller than P. cubiformis and the structure looks very different (at least superficially). The flowers of this species don’t really smell much.

Close-up of a flower of P. mccoyi. The flower is approximately 5 mm wide.

I’ve also had a bit more flowering from my Adenium, with A. multiflorum continuing to flower, but now also joined by one A. obesum. At this age all of A. multiflorum, A. obesum and A. arabicum look rather similar superficially, with only some small differences in leaf shape. The flower colour between A. multiflorum and A. obesum was very different, though I’m not sure how variable the flower colour is or whether it stays true to the species. I am not even sure whether the above three are really separate species or just forms of one variable species.

Adenium multiflorum with pretty pink and white flowers.

A. multiflorum flower at very close range.

Adenium obesum with flowers that look more or less identical in structure to A. multiflorum, only with a different flower colour. The deep pinkish-red colour is very attractive, though.

A zoomed out picture of the A. obesum pictured above.

A few months ago Lithops werneri produced a flower, so far being the only species of Lithops that have decided to start doing so. Two plants of this species have flowered now, and both kept the flowers open for over a week.

Lithops werneri with a tall flower tube.

Close-up of the flower of L. werneri, showing a pretty yellow colour.

My Turbinicarpus longispinus, much like the Pseudolithos, have simply kept on flowering continuously for a year now (also see previous post on this species). I am surprised that they aren’t taking a break. I suppose my conditions with the artificial light and regular watering might simply be confusing them into believing that they’re in a never ending flowering season. It is also a bit surprising that this species is so ready to flower, while other Turbinicarpus species I have that are just as old and by their physical appearance should be ready to flower, have not yet done so. I expect the reason must simply be that some species of the genus require a (probably cooler) resting period while others don’t need this in order to flower.

Turbinicarpus longispinus in flower.

The last pictures in this update are of two new Mammillaria species flowering for the first time. Some decades ago these two species were thought to belong to a different genus than Mammillaria and the genus Solisia was erected for the two of them. I’m not really sure exactly why this was done and especially not why these two species were thought to deserve their own genus. Apart from some physical similarities (particularly spination) I don’t really see a close resemblance between them, and the genus Solisia was abandoned a long time ago.

Mammillaria solisioides showing both flower and buds. The flower is approximately 3 cm wide.

Close-up of the flower of M. solisioides. The heat from the lamps has caused the petals of this flower to bend backwards.

Mammillaria pectinifera with a large bud. So far this is the only plant of this species that has flowered.

M. pectinifera with the flower just opened. The colour is a very pretty and delicate shade of pinkish-white with a slightly darker mid-stripe on the petals.

M. pectinifera with the flower wide open. The flower is approximately 2,5 cm wide.

That’s it for this post. Hopefully there’ll be some more flowering in the nursery over the coming months for me to show, but the next post will be about plants in my greenhouse.