Repotting guide

When & how to repot Cardboard Cycad (Encephalartos horridus)

Also called Eastern Cape Blue Cycad.

More about cardboard cycad

About Cardboard Cycad

Encephalartos horridus · also called Eastern Cape Blue Cycad · houseplant

Encephalartos horridus is a striking dwarf South African cycad famous for its stiff, intensely blue-grey fronds armed with vicious, twisted spines. Slow-growing and architectural, it is a collector's prize, but its fierce spines and severe cycad toxicity make it a plant to site carefully away from pets.

Mature size: Generally stays around 0.9-1.2 m tall and wide, occasionally larger with great age; one of the more compact Encephalartos for container culture.

How to tell cardboard cycad needs repotting

Repotting on a calendar is less reliable than reading the plant. For cardboard cycad, 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 cardboard cycad

Every 2–3 years, into bone-dry mix. Cardboard Cycad's growth habit — compact, usually solitary dwarf cycad with a short, stout trunk and a dense rosette of rigid, recurved, heavily spined blue-grey fronds. very slow-growing and sculptural. — sets the pace. Encephalartos horridus is a striking dwarf South African cycad famous for its stiff, intensely blue-grey fronds armed with vicious, twisted spines. Slow-growing and architectural, it is a collector's prize, but its fierce spines and severe cycad toxicity make it a plant to site carefully away from pets.

What size pot to step cardboard cycad up to

Use a pot only one size up — or even the same pot with fresh gritty mix if the roots have room. Cardboard Cycad 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 cardboard cycad

Spring or summer, while cardboard cycad 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 cardboard cycad

Repot dry. Do not water cardboard cycad 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 very gritty, sharply draining mineral mix 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 cardboard cycad 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 cardboard cycad 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 cardboard cycad

Cardboard Cycad wants very gritty, sharply draining mineral mix. A largely mineral, fast-draining mix of grit, pumice and coarse sand with only a little loam. This arid-zone cycad demands exceptionally sharp drainage around its caudex. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.

Repotting cardboard cycad — frequently asked questions

How often should you repot cardboard cycad?

Every 2–3 years, into bone-dry mix for cardboard cycad. Repot cardboard cycad every 2–3 years into a snug pot of very gritty, sharply draining mineral mix, 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 cardboard cycad need?

When is the best time of year to repot cardboard cycad?

Should you water cardboard cycad after repotting?

No — not straight away. Repot cardboard cycad 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 cardboard cycad after repotting?

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