Repotting guide

When & how to repot Pyrenean Merendera (Merendera montana)

Also called Pyrenean merendera, Pyrenean mountain saffron, Spanish merendera.

More about pyrenean merendera

About Pyrenean Merendera

Merendera montana · also called Pyrenean merendera, Pyrenean mountain saffron · flowering

Merendera montana (syn. Colchicum montanum) is a small autumn-flowering cormous perennial in the family Colchicaceae, endemic to the Iberian Peninsula and Pyrenees where it colonises montane and subalpine grasslands up to 2,300 m. Its slender star-shaped lilac-pink to rosy-purple flowers appear at ground level in late summer and early autumn before the narrow strap-like leaves emerge, making it ideal for a sunny rock garden or alpine trough. Plant corms 8–10 cm deep in a sharply drained, gritty soil in a sunny, open position. All parts are highly toxic — the plant contains colchicine and related tropolone alkaloids.

Mature size: 5–10 cm tall in flower, 5–8 cm spread.

Watch for — Corm rot in wet winters: Heavy clay soils or poor drainage in winter will cause corms to rot; grow in a raised alpine bed with a deep grit layer, or in a pot moved under cover during prolonged wet spells.

How to tell pyrenean merendera needs repotting

Repotting on a calendar is less reliable than reading the plant. For pyrenean merendera, watch for these signs:

Roots growing out of the drainage holes, or the rootball lifting the plant proud of the rim.
Soil that has shrunk away from the pot sides and no longer holds water.
The pot is unstable because the plant has grown top-heavy.
Old, compacted, broken-down mix that stays wet too long — for a succulent that is a rot risk, so refresh it even if the pot size is fine.

For the underlying biology of a pot-bound root system and why it stalls a plant, see our guide to spotting and fixing a root-bound plant.

How often to repot pyrenean merendera

Every 2–3 years, into bone-dry mix. Pyrenean Merendera's growth habit — dwarf, clump-forming cormous perennial with a crocus-like autumn-flowering habit. — sets the pace. Merendera montana (syn. Colchicum montanum) is a small autumn-flowering cormous perennial in the family Colchicaceae, endemic to the Iberian Peninsula and Pyrenees where it colonises montane and subalpine grasslands up to 2,300 m. Its slender star-shaped lilac-pink to rosy-purple flowers appear at ground level in late summer and early autumn before the narrow strap-like leaves emerge, making it ideal for a sunny rock garden or alpine trough. Plant corms 8–10 cm deep in a sharply drained, gritty soil in a sunny, open position. All parts are highly toxic — the plant contains colchicine and related tropolone alkaloids.

What size pot to step pyrenean merendera up to

Use a pot only one size up — or even the same pot with fresh gritty mix if the roots have room. Pyrenean Merendera stores water and rots in a large pot of slow-drying soil. A tight terracotta pot that dries fast is far safer than a generous plastic one. Never up-pot a succulent by several sizes.

Not sure of the exact diameter? Our pot size calculator takes the current pot and root spread and tells you the right next size — it deliberately recommends a single step up, never a big jump.

The best time of year to repot pyrenean merendera

Spring or summer, while pyrenean merendera is in active growth and warm, is best — roots recover fastest then, and the plant is not sitting in cool damp soil. Avoid repotting a succulent in winter dormancy.

Step-by-step: repotting pyrenean merendera

Repot dry. Do not water pyrenean merendera for several days first. Working with dry roots and dry mix dramatically lowers the rot risk for a succulent.
Pick a snug, fast-draining pot. Choose terracotta one size up at most, with a drainage hole. Have gritty sharply drained, gritty loam; neutral to alkaline ready.
Tip it out and clean the roots. Slide the plant out, crumble off the old soil, and trim any black, mushy or dead roots with clean snips.
Pot into dry mix. Set pyrenean merendera at its original depth in dry gritty mix, firming gently. Do not bury the stem deeper than it was.
Wait a week before watering. Leave it completely dry and out of harsh sun for about 7 days so any damaged roots callus. Only then water lightly.

Aftercare

Keep pyrenean merendera completely dry and out of fierce sun for about a week so any nicked roots callus before they meet moisture; watering a freshly repotted succulent is the classic way to rot it. Then resume the normal lean, dry rhythm. Do not fertilise for about 3 weeks — fresh mix already carries nutrients and feeding freshly disturbed roots scorches them.

The right soil mix for pyrenean merendera

Pyrenean Merendera wants sharply drained, gritty loam; neutral to alkaline. A mix of two parts loam, one part grit or fine gravel, and one part leaf mould suits this alpine species well; avoid clay-heavy soils that retain winter moisture around the corms. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.

Repotting pyrenean merendera — frequently asked questions

How often should you repot pyrenean merendera?

Every 2–3 years, into bone-dry mix for pyrenean merendera. Repot pyrenean merendera every 2–3 years into a snug pot of sharply drained, gritty loam; neutral to alkaline, ideally in spring or summer. Let it sit in dry soil and do not water for about a week afterwards so any nicked roots can callus. Over-potting and watering straight away is what rots succulents.

What size pot does pyrenean merendera need?

When is the best time of year to repot pyrenean merendera?

Should you water pyrenean merendera after repotting?

No — not straight away. Repot pyrenean merendera into dry mix and wait about a week before the first watering so any damaged roots callus over. Watering a freshly repotted succulent is the single most common way to rot one.

Should you fertilise pyrenean merendera after repotting?

Not immediately. Wait about 3 weeks after repotting pyrenean merendera. Fresh mix already contains nutrients, and feeding freshly cut or disturbed roots burns them. Resume your normal feeding routine once you see new growth.