Why a clone cannot pollinate itself

A Trichocereus flower is said to be unable to set seed with pollen — what Pollen means from its own plant, or from any cutting of that plant. Not the flower beside it. Not a piece sold years ago and bought back. Same plant, no seed. No technique is known to get around it, growers say.

Cut a column in half and you have two pieces of one plant, not two plants. Nothing was mixed, so the genetics are identical. A hundred cuttings off one mother are one individual with a hundred root systems.

Move pollen between two of those cuttings and you are handing a flower its own pollen. These plants are said to be self-sterile — what Self-sterile (not self-fertile) means: a flower given its own pollen sets nothing. It withers and drops, base and all, as if you never touched it, growers say.

Every flower makes pollen and can carry fruit, growers say. What blocks a cross is sameness. Pollen has to come from a genetically different individual, and a different pot does not count.

That last line gives you a free test. Think two plants are one clone under two names? Cross them. Fruit means they are not clones — siblings or strangers. A failure proves less, growers say, since bad timing and dead pollen fail too. A fruit is proof.

Seed always has two parents and always makes new individuals. So the only way to keep one particular plant is to keep cutting it into pieces. Every named clone is a chain of cuttings back to one original. The name is a claim about that chain.

A cross gives the same deal. Pollen from one good plant onto another fills the fruit with new individuals, none of them either parent, no two quite alike. That is the appeal of breeding, and the caution that belongs on every seed packet.

Growers tell the story of somebody who buys several cuttings from one seller, waits three years for flowers, hand-pollinates carefully, and gets nothing. The cuttings were all off the same plant.

So buy for difference, growers say: visibly different strains, or different species outright, from different sources. A rooted cutting tells you nothing about which mother it came off, growers say. Signs of a repotted cutting rather than a seedling, growers say:

Cuttings are still the fastest route to seed, growers say. A seedling takes many years to reach flowering size, growers say. Just use cuttings of different plants, growers say.

A packet labeled as a cross of two famous clones contains, growers say, neither. It contains their children. Some will beat both parents, most will not, and a seedling will not tell you which for years, growers say. That is the point of seed, not a flaw. It turns bad only when somebody sells a seedling under a parent's name, growers say. That happens.

Buy a cutting and you get the actual plant. Buy seed and you get a shuffle of its children.