Meet Trichocereus

If you live anywhere warm, you have probably walked straight past one of these. A tall ribbed blue-green column standing in a front garden, higher than the fence, quietly getting on with it. Almost none of them were grown from a seed. Almost every one is a piece cut off another plant, stood in some soil and left alone. That single fact explains most of what follows.

Trichocereus — what Trichocereus means is a group of columnar cacti from the Andes, and the mountains are the part that matters. Their home ground is high country down the western side of South America — real rainfall and heavy dew, cold nights, nothing like the hot sand most people picture when somebody says cactus.

Turn that around and you have the rule this whole hub rests on. In habitat the warm season is the wet one and the cold season is the dry one. So these plants drink far more than a desert cactus through a hot summer, and want to be left dry through winter. They are also hungry by cactus standards, which catches out anyone who has only kept a windowsill succulent.

Five words cover nearly everything you will read on a listing.

The rib — what Rib means trick is the single most useful thing on this page. A cactus cannot droop the way a thirsty leafy plant does, so it has to tell you in another language, and the ribs are that language.

A column gets longer at the tip and gets more numerous at the areoles — what Areole means. Those are two different things, and mixing them up causes a lot of needless worry.

A tip that stops getting longer has terminated. It is not damage, and nothing has gone wrong — the tip carries on fattening and the plant puts its effort into branching instead. Cut a healthy column and it usually answers with two or three new heads, which is why taking a cutting — what Cutting means is a way of making more of these plants rather than losing one.

Speed depends almost entirely on where you live. A San Diego grower reckons on one to three feet a year. A grower in Barcelona measured 22, 20 and 17 inches on three plants in one season, then moved the same collection north and watched it run at under half that pace. In the wild they reach about seven metres before the wind snaps them, and the fallen pieces simply root where they land.

Almost everything sold under these names falls into one of four species, and the differences are the ones growers actually look at first: how many ribs, how long the spines, and what the skin — what Epidermis means looks like.

Treat that as a rough guide and nothing firmer. These species grade into one another in the wild, they look different young and mature, and sun, water and age move every feature on the list. The formal naming has been revised more than once and is still argued over: under recent revisions macrogonus — what Macrogonus means is the older and therefore the official name, and a fair amount of what the trade calls peruvianus — what Peruvianus means would fold into it. The hobby carries on using all of them anyway.

This is the promise we make on every page of this site, so it is worth showing our working.

Count the ribs on a row of plants of one clone — what Clone means standing next to each other and you can find six, seven and eight on identical genetics — which finishes rib count as a way of telling clones apart, and colour goes with it. Growing conditions and age move everything else on the list too, and real certainty needs flowers or laboratory work.

So we will gladly tell you what we can see in your photograph — rib count, spine type, colour, size — and we will not put a name on it. Every name on this site is the label the plant arrived carrying, and we will tell you where that label came from.