Taking inspiration from a recent comment one of my readers made about grafting, I thought I’d write a post about it. In fact, I’ll write five. Some of the posts I’ve written before have become far too big so, instead of writing one monster post, this time I thought I’d split it up in more manageable parts. The first three parts will be about the how and why of grafting, the fourth part will be about the choice of either degrafting or keeping a plant permanently grafted, while the last part will deal with some of the different grafting stocks that are in use.
Grafting cacti is usually very easy. The family is uncommon among plants in that almost every cactus can easily be grafted on members of only distantly related genera. I suppose the genus Pereskia is an exception to this, being hardly succulent at all, although I’ve never actually tried grafting them. While it might technically be possible to graft any cactus on any other cactus, not all cacti are suitable as stock plants.
With grafting, the two main players are the stock and the scion. The stock is what one uses to graft on, while the scion is the bit that’s being grafted. This will usually involve the stock losing its head, while the scion is separated from its lower body. The scion is placed atop the stock and, once the two parts fuse together, a more or less happy marriage ensues. For as long as the union lasts, the scion will draw all the nutrients it needs from the stock. The stock itself should be in perfect health, it shouldn’t be too big or too small with regards to the scion, and the graft should only be made on new and healthy tissue.
The most straightforward and common way to graft cacti is to cut both stock and scion “horizontally” across the body so that the scion will fit nicely on top of the stock. As mentioned in the previous post, it’s important that there isn’t a huge size difference between the two parts. However, some cacti that grow long thin (or thin-ish) shoots that might be difficult to graft “standing up”, can be cut laterally along the body and then pressed down on the horizontal surface of the stock. Areoles on the scion will then go on to produce shoots. The members of the genus Echinocereus that were formerly known as Wilcoxia are perhaps candidates for this method.
It’s also possible to graft tubercles of some species. I have attempted to do this with an Ariocarpus trigonus that suddenly decided to head for the great desert in the sky. A few healthy tubercles were left, but not enough to graft normally, so I decided to try and graft a couple of the tubercles. Only one is still alive (after three years) although it hasn’t done much except not die. The idea is that the tubercle will be able to sprout a new growing point from it’s base from which the plant will be able to regrow and form a new normal looking Ariocarpus. Apart from Ariocarpus, I’ve read that certain mammillarias and some members of other genera are able to regrow from a single tubercle in this way. It remains to be seen whether my attempt will ultimately prove successful.
The top that was removed from the stock may be set to root or be discarded. To avoid the possibility of virus infections it is recommended that stocks be grown from seed and only used once, i.e. no parts of it are reused. As far as I know I have never had any trouble with viruses on stock plants, but then virus infections are a very little studied phenomenon in cacti. It may be more widespread than we think, or the danger of it may be very exaggerated. I have often used stock plants several times and often taken cuttings from older stock plants to use. And for some stock plants, such as Pereskiopsis, seed is hardly, if ever, available. The remains of the scion may also be left to continue to grow and set new shoots unless it’s a rescue job, of course.
It may seem irreverent to cut and slice our plants open, but a lot can be learned from it. It can be fun to try and see how quickly you can manage to grow a species, or you might be interested in trying out different stock plants to see which suits best for a particular species. Grafting can allow you to witness your plants flowering years ahead of time, or let you save just that one very special plant that has begun to rot. Grafting can be a method to grow plants you might not otherwise be able to grow on their own roots, or you might simply find grafted plants attractive. Whatever the reason for grafting, it is certainly a worthwhile practice to know and understand.