Repotting guide

When & how to repot Four-angled cassiope (Cassiope tetragona)

Also called Four-angled cassiope, Arctic white heather.

More about four-angled cassiope

About Four-angled cassiope

Cassiope tetragona · also called Four-angled cassiope, Arctic white heather · flowering

Four-angled cassiope is a compact arctic-alpine subshrub bearing tightly scale-like leaves arranged in four ranks along its stems, giving them a distinctive square cross-section. Solitary white bell-shaped flowers dangle from wiry red stalks in late spring. It thrives in cool, moist, acidic conditions and is suited to rock gardens in cold climates.

Mature size: 10–30 cm tall (4–12 in), slowly spreading to 20–40 cm wide

Watch for — Root rot in warm/wet summers: Cassiope tetragona is extremely sensitive to summer heat and waterlogging. In warm climates, ensure perfect drainage and position in a cool north- or east-facing aspect. Alpine house culture is often necessary in warmer temperate zones.

How to tell four-angled cassiope needs repotting

Repotting on a calendar is less reliable than reading the plant. For four-angled cassiope, 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 four-angled cassiope

Every 2–3 years, into bone-dry mix. Four-angled cassiope's growth habit — low, mat-forming or cushion subshrub with erect, four-angled stems densely clothed in scale-like leaves — sets the pace. Four-angled cassiope is a compact arctic-alpine subshrub bearing tightly scale-like leaves arranged in four ranks along its stems, giving them a distinctive square cross-section. Solitary white bell-shaped flowers dangle from wiry red stalks in late spring. It thrives in cool, moist, acidic conditions and is suited to rock gardens in cold climates.

What size pot to step four-angled cassiope up to

Use a pot only one size up — or even the same pot with fresh gritty mix if the roots have room. Four-angled cassiope 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 four-angled cassiope

Spring or summer, while four-angled cassiope 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 four-angled cassiope

Repot dry. Do not water four-angled cassiope 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 peaty or humus-rich, well-drained, acidic 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 four-angled cassiope 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 four-angled cassiope 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 four-angled cassiope

Four-angled cassiope wants peaty or humus-rich, well-drained, acidic. Requires strongly acidic soil (pH 4.5–6.0). A mix of ericaceous compost, gritty sand, and perlite provides both the acidity and drainage this species needs. It is intolerant of alkaline or heavy clay soils. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.

Repotting four-angled cassiope — frequently asked questions

How often should you repot four-angled cassiope?

Every 2–3 years, into bone-dry mix for four-angled cassiope. Repot four-angled cassiope every 2–3 years into a snug pot of peaty or humus-rich, well-drained, acidic, 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 four-angled cassiope need?

When is the best time of year to repot four-angled cassiope?

Should you water four-angled cassiope after repotting?

No — not straight away. Repot four-angled cassiope 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 four-angled cassiope after repotting?

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