San Pedro Cutting Peruvianus 25cm

1. San Pedro Cutting Peruvianus 25cm

A 25 cm cutting of Trichocereus peruvianus, the Peruvian torch — a fast-growing columnar cactus from the high slopes of the Peruvian Andes, and the most immediately recognisable of the San Pedro group: glaucous blue-green skin with robust honey-brown spines.

Each cutting is taken from mature, healthy mother plants and cured for ten to fourteen days before it leaves us, so the cut face is fully calloused on arrival and it can go straight into soil.

The specification that tells you most about how to treat it is one almost nobody publishes: this cutting is 90 to 95% water by weight. Section 3 explains why that number matters.

2. Specifications

3. Water weight

A 25 cm cutting weighs somewhere between 200 and 800 grams, and nine tenths of that is water. That single fact explains most of what a cutting needs and most of what kills one:

• It is carrying its own supply. A cutting has no roots and cannot take up water, so everything it needs to survive shipping and to grow its first roots is already inside it. This is why a 25 cm cutting works and a 5 cm one struggles.
• Which is why it does not need watering immediately. The instinct to water a newly planted cutting comes from thinking of it as a thirsty plant. It is not. It is a full reservoir looking for somewhere to put roots.
• And why watering early kills it. A cut face in wet soil takes up water it has no way to use, and the tissue rots from the base. Nine tenths water plus more water is the problem.
• It also explains the weight range. 200 to 800 grams for the same length is mostly hydration, not size. A firmer, heavier cutting has more reserve; a lighter one is not defective.
• And why light shrinkage in the first weeks is normal. The cutting is drawing on its own reserves to build roots. Slight softening or wrinkling early on is the plant doing exactly what it should.

3.1 What that means on arrival

1. Plant it shallow in gritty soil and stake it if it will not stand.
2. Do nothing for a week to ten days. No water, no misting, no fussing.
3. Then water once, thoroughly, and let it dry out completely before the next.
4. Watch for new growth at the tip, which is the first visible sign that it has rooted. Do not pull it up to check.
5. Build the light up over two to three weeks before full sun.

After that it is straightforward: 15 to 40 cm of new growth a year in good conditions, sharp drainage, generous summer water and nothing at all from October.

4. Planting and care

4.1 On arrival

1. Inspect the cut face: dry, firm, no softness at the centre.
2. Shallow planting in a sharp, gritty mix, upright and supported if necessary.
3. Seven to ten days with no water at all.
4. Soak and dry from then on, and only when the soil is dry through.
5. Full sun only after two to three weeks of gradual exposure.

4.2 Ongoing

• Soil: free-draining and gritty. A cactus mix cut with extra pumice, perlite or coarse sand. Trichocereus tolerates organic content better than Lophophora and still hates sitting wet.
• Water: soak and dry through the growing season, roughly every one to two weeks in summer depending on heat and pot size. Never on a schedule.
• Winter: dry, bright and frost-free from October. Watering a dormant column is how they rot at the base.
• Feeding: a dilute cactus feed through the growing season only.
• Support: a fast-growing column gets top-heavy. A cane is sensible rather than an admission of failure.

Nine tenths of a cutting is water. It is not a thirsty plant looking for a drink — it is a full reservoir looking for somewhere to put roots.