Whether it arrives as a rooted plant or a freshly rooted cutting, how you plant a San Pedro sets it up for years of growth. The rules are simple: fast drainage, the right depth and firm support.
Pots
Material. Terracotta is the best choice for most growers. It is heavy, which helps keep tall columns upright, and it breathes, so the soil dries out evenly. Plastic works, but hold back more on watering.
Size. Choose a pot only a few centimetres wider than the root ball. A huge pot holds too much wet soil around small roots. For columns over a metre tall, choose a wide, heavy pot for stability, or add a layer of gravel at the bottom for weight.
Drainage. Every pot must have a drainage hole. Never let a pot stand in a saucer of water.
The soil mix
San Pedro wants a mix that drains within seconds of watering. A reliable recipe:
- 50–60% mineral material: pumice, perlite, coarse sand (not fine beach sand), lava grit or crushed volcanic stone
- 40–50% organic material: a good cactus compost or standard potting compost
Top-dress with a layer of gravel. It keeps the base of the stem dry and looks tidy.
Planting step by step
- Plant into dry soil, with the plant’s roots also dry.
- Set the plant at the same depth it grew before. For a rooted cutting, bury only the first few centimetres.
- Firm the mix around the base so the column stands upright. For tall plants, tie them loosely to a bamboo cane or stake with soft cord until the roots take hold.
- Wait about a week before the first watering. Any roots damaged during planting need time to heal first.
Repotting
Repot every two to three years, or when roots circle the pot or grow out of the drainage hole. Late spring is the best time. Hold the column with a towel or newspaper, tip the pot, and ease the plant out. Shake off old soil and trim any dead or mushy roots before replanting.
Planting in open ground
In much of Spain, San Pedro thrives outdoors all year:
- Position. A sunny spot with shelter from the coldest winds. A south-facing wall is ideal.
- Drainage. On heavy clay, plant on a raised mound or bed mixed with plenty of grit. Standing winter water is the main killer.
- Acclimatisation. Plants raised in shade or indoors can sunburn. Introduce them to full sun gradually over two to three weeks, or give light shade cloth for the first summer.
- Spacing. Allow at least a metre between plants. San Pedro branches into a wide clump with time.
- Frost. Established plants tolerate light frost (around −2 °C) if the soil is dry. In colder areas, cover them with fleece on frosty nights.
Planted with good drainage and support, a San Pedro will settle in within a season and start producing strong new growth the following spring.