Repotting guide

When & how to repot King Sundew (Drosera regia)

Also called king sundew, regal sundew.

More about king sundew

About King Sundew

Drosera regia · also called king sundew, regal sundew · houseplant

King sundew is the largest sundew, native to a single South African valley, with strap-like leaves to 70 cm tipped in glistening, insect-trapping mucilage. It demands bright light, pure water, a peat-sand carnivorous mix, and a winter cool rest. Feed it gnats, not fertiliser. A temperamental but spectacular carnivore.

Mature size: Leaves 25-70 cm long; the whole plant spans roughly 30-50 cm across when well grown.

Watch for — Root rot in stagnant warmth: King sundew has a sensitive root system; constant warm, airless, soggy conditions invite rot. Give airflow and let it cool in winter rather than baking it year-round.

How to tell king sundew needs repotting

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

Roots spiralling thickly out of the drainage holes or pushing the whole plant up out of the pot.
The pot is so packed that water runs straight through in seconds and barely wets the soil.
It has split a plastic pot, or the rootball is a solid mass with almost no soil left when you slide it out.
Growth and (for king sundew) flowering have clearly stalled despite good light and feeding — but remember this plant likes being snug, so a little crowding alone is not a reason to repot.

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 king sundew

Only every 2–4 years, when genuinely crowded. King Sundew is one of the plants that genuinely prefers a snug pot — it grows and flowers better with its roots a little restricted, so resist the urge to repot it on schedule. Rosette-forming perennial sundew with long, narrow, semi-erect strap leaves that uncoil and arch; older leaves can reach 40-70 cm, the longest of any Drosera..

What size pot to step king sundew up to

Go up only one pot size — roughly 2–3 cm (about an inch) wider in diameter, no more. King Sundew positively prefers a snug pot: it flowers and grows better when the roots are a little restricted. The single biggest repotting mistake here is over-potting — dropping king sundew into a pot two or three sizes up. All that surplus soil holds water the small root system cannot use, stays cold and wet, and rots the roots within weeks. When in doubt, choose the smaller pot.

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 king sundew

Early spring, just as new growth restarts, is the ideal window for king sundew. The plant is moving into its strongest growth phase and re-roots into fresh soil quickly. Avoid repotting in winter dormancy or, for flowering plants, while it is in bud or bloom — recovery is slowest then and you risk dropping the flowers.

Step-by-step: repotting king sundew

Confirm it actually needs it. Slide king sundew out and check the roots. Only continue if it is genuinely packed — this plant prefers a snug pot, so if there is still soil and room, put it straight back.
Pick a pot only one size up. Choose a pot just 2–3 cm wider with good drainage. Resist anything bigger; over-potting is the main killer here.
Ease it out gently. Water lightly the day before, then tip king sundew out, supporting the base. Tease the outer roots free only enough to stop them circling.
Repot at the same depth. Add a layer of fresh nutrient-free carnivorous mix, set the plant so the soil line sits exactly where it did before, and backfill around the sides, firming lightly.
Settle it in. Water once to settle the soil, then let it sit. Hold off on more water until the top of the soil dries — fresh soil around a small root system stays wet for a while.

Aftercare

Because the new soil holds more water than the old crammed rootball did, ease right back on watering — let the top of the soil dry before you water king sundew again, or you will rot the roots in the very pot you just moved it to. Keep it out of harsh direct sun for a fortnight. Do not fertilise for about 4 weeks — fresh mix already carries nutrients and feeding freshly disturbed roots scorches them.

The right soil mix for king sundew

King Sundew wants nutrient-free carnivorous mix. Classic blend of sphagnum peat with sharp silica sand or perlite (roughly 1:1). Never use ordinary potting soil, compost or anything with added fertiliser, which scorches the fine roots. Many growers favour pure long-fibre sphagnum for this species. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.

Repotting king sundew — frequently asked questions

How often should you repot king sundew?

Only every 2–4 years, when genuinely crowded for king sundew. Only repot king sundew every 2–4 years, and only when it is genuinely root-bound — it flowers and grows best slightly crowded. Step up just one pot size in spring using nutrient-free carnivorous mix. The key mistake is over-potting: a too-big pot stays wet and rots the roots.

What size pot does king sundew need?

When is the best time of year to repot king sundew?

Does king sundew like to be root-bound?

Yes — king sundew genuinely flowers and grows best when slightly pot-bound, so do not rush to repot it. The mistake to avoid is over-potting into a much larger pot: the excess soil stays wet, the roots cannot use it, and the plant rots. Only repot every few years and only one snug size up.

Should you fertilise king sundew after repotting?

Not immediately. Wait about 4 weeks after repotting king sundew. Fresh mix already contains nutrients, and feeding freshly cut or disturbed roots burns them. Resume your normal feeding routine once you see new growth.