Why a clone cannot pollinate itself

Here is the fact first, with nothing in front of it. A Trichocereus — what Trichocereus means flower cannot be fertilised by pollen — what Pollen means from the plant it is growing on, or from any cutting — what Cutting means of that same plant. Not from the flower beside it. Not from a piece you sold to somebody three states away and bought back a decade later. Same plant, no seed, and no amount of technique gets around it.

This is the part everyone nods along to and then quietly forgets. Cut a column in half and you have not made a second plant — you have made two pieces of one. The genetics are identical, because nothing has been mixed. A hundred cuttings off one mother are a hundred pieces of a single individual with a hundred separate root systems.

So when two of those cuttings flower on the same night and you move pollen between them, what you are actually doing is handing a flower its own pollen. These plants are self-sterile — what Self-sterile (not self-fertile) means, and a flower that receives its own pollen sets nothing at all. It withers and drops, base and all, exactly as if you had never touched it.

Worth killing this one early, because it sends people hunting for something that does not exist. Every Trichocereus flower carries both halves: it makes pollen, and it can carry fruit. The plant is not the problem. Sameness is the problem, and a flower needs pollen from a genetically different individual — which is a much stricter test than a different pot.

That last line hands you a free test. If you suspect two plants in your yard are the same clone — what Clone means under two different names, put them together. Fruit means they are not clones — they are siblings, or strangers. A failure is weaker evidence, because bad timing and dead pollen fail too, but a fruit is proof.

Follow it through and the whole shape of this hobby falls out of one genetic fact.

If seed copied a plant, nobody would need cuttings. You would buy a packet of your favourite clone the way you buy tomato seed and grow a hundred of it. But seed here always has two parents and always makes new individuals, so the only way to keep hold of one particular plant is to keep cutting it into pieces. Every named clone in circulation is a chain of cuttings running back to a single original, and the name is a claim about that chain.

It also settles what a cross — what Cross means actually gives you. Put pollen from one good plant onto another and the fruit fills with new individuals — none of which is either parent, and no two of which are quite alike. That is the entire appeal of breeding, and it is also the honest warning on every seed packet.

Somebody decides to make seed. They buy several cuttings from one seller, wait three years for flowers, hand-pollinate carefully, and get nothing. The cuttings were all off the same plant.

So when you buy for breeding, buy for difference — visibly different strains, or different species outright, from different sources. And know that a plant which arrived as a rooted cutting tells you nothing about which mother it came off. The tells that you are looking at a repotted cutting rather than a seedling are a base far too fat for the plant's height, a thin stretched section where it etiolated — what Etiolation means, and a cut scar at the bottom.

Cuttings are still the fastest route to seed, because a seedling is roughly ten to fifteen years from its first flower. Just make sure they are cuttings of different plants.

A packet labelled as a cross between two famous clones contains neither of them. It contains their children. Some will be better than both parents, most will not, and a seedling will not tell you which for years. That is not a criticism of seed — it is the point of seed. It only becomes a problem when somebody sells you a seedling under a parent's name, which does happen.

The other side of the same coin is why growers care about cuttings at all. Buy a cutting and you are buying the actual plant. Buy seed and you are buying a shuffle of its children.