Repotting guide

When & how to repot Bastard Cobas (Cyphostemma juttae)

Also called Bastard Cobas, Namibian Grape, Tree Grape.

More about bastard cobas

About Bastard Cobas

Cyphostemma juttae · also called Bastard Cobas, Namibian Grape · tropical

Cyphostemma juttae is a dramatic Namibian succulent with a thick, pale, peeling caudex trunk, grape-like clusters of red berries, and large blue-green leaves. One of the most sculptural of all African succulents, it demands intense light, extremely fast-draining soil, and minimal winter water. A stunning specimen for warm-climate gardens or conservatories.

Mature size: Up to 2 m (6 ft) tall in cultivation, taller in habitat; trunk to 60 cm (24 in) diameter in very old specimens.

How to tell bastard cobas needs repotting

Repotting on a calendar is less reliable than reading the plant. For bastard cobas, 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 bastard cobas

Every 2–3 years, into bone-dry mix. Bastard Cobas's growth habit — arborescent caudiciform succulent; develops a stout, bottle-shaped trunk with papery, peeling yellow-green bark, deciduous large lobed leaves, and pendant grape-like fruit clusters. — sets the pace. Cyphostemma juttae is a dramatic Namibian succulent with a thick, pale, peeling caudex trunk, grape-like clusters of red berries, and large blue-green leaves. One of the most sculptural of all African succulents, it demands intense light, extremely fast-draining soil, and minimal winter water. A stunning specimen for warm-climate gardens or conservatories.

What size pot to step bastard cobas up to

Use a pot only one size up — or even the same pot with fresh gritty mix if the roots have room. Bastard Cobas 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 bastard cobas

Spring or summer, while bastard cobas 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 bastard cobas

Repot dry. Do not water bastard cobas 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 coarse, mineral-heavy succulent 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 bastard cobas 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 bastard cobas 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 bastard cobas

Bastard Cobas wants very coarse, mineral-heavy succulent mix. A highly mineral mix is essential: 60–70% coarse grit, pumice, or perlite combined with 30–40% quality cactus compost. This species originates from rocky, near-desert soils in Namibia. Standard potting compost or any peat-based mix will cause root rot. Use large, heavy terracotta or clay pots to accommodate the developing 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 bastard cobas — frequently asked questions

How often should you repot bastard cobas?

Every 2–3 years, into bone-dry mix for bastard cobas. Repot bastard cobas every 2–3 years into a snug pot of very coarse, mineral-heavy succulent 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 bastard cobas need?

When is the best time of year to repot bastard cobas?

Should you water bastard cobas after repotting?

No — not straight away. Repot bastard cobas 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 bastard cobas after repotting?

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