Repotting guide

When & how to repot Slender-Leaved Sundew (Drosera linearis)

Also called slender-leaved sundew, linear-leaved sundew.

More about slender-leaved sundew

About Slender-Leaved Sundew

Drosera linearis · also called slender-leaved sundew, linear-leaved sundew · houseplant

Drosera linearis is a delicate North American temperate sundew native to cold, alkaline calcareous bogs — unusual among sundews in tolerating and even preferring limestone-influenced water with slightly higher pH. Narrow upright leaves bear glistening red mucilage glands. Requires cold dormancy and is one of the more challenging sundews for indoor cultivation.

Mature size: Leaves to 5–8 cm (2–3 in) long; rosette diameter 3–6 cm (1–2 in)

How to tell slender-leaved sundew needs repotting

Repotting on a calendar is less reliable than reading the plant. For slender-leaved 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 slender-leaved 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 slender-leaved sundew

Only every 2–4 years, when genuinely crowded. Slender-Leaved 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. Compact rosette of narrow, upright strap-like leaves densely covered in red stalked glands.

What size pot to step slender-leaved sundew up to

Go up only one pot size — roughly 2–3 cm (about an inch) wider in diameter, no more. Slender-Leaved 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 slender-leaved 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 slender-leaved sundew

Early spring, just as new growth restarts, is the ideal window for slender-leaved 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 slender-leaved sundew

Confirm it actually needs it. Slide slender-leaved 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 slender-leaved 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 calcareous or neutral mineral mix: live sphagnum or a sand-limestone grit blend, 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 slender-leaved 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 slender-leaved sundew

Slender-Leaved Sundew wants calcareous or neutral mineral mix: live sphagnum or a sand-limestone grit blend. Unlike most sundews, D. linearis grows in calcium-rich, near-neutral to slightly alkaline substrate (pH 6–7.5). A mix of coarse quartz sand with small amounts of crushed limestone or pure live sphagnum on calcareous substrate is ideal. Peat alone is too acidic. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.

Repotting slender-leaved sundew — frequently asked questions

How often should you repot slender-leaved sundew?

Only every 2–4 years, when genuinely crowded for slender-leaved sundew. Only repot slender-leaved 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 calcareous or neutral mineral mix: live sphagnum or a sand-limestone grit blend. The key mistake is over-potting: a too-big pot stays wet and rots the roots.

What size pot does slender-leaved sundew need?

When is the best time of year to repot slender-leaved sundew?

Does slender-leaved sundew like to be root-bound?

Yes — slender-leaved 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 slender-leaved sundew after repotting?

Not immediately. Wait about 4 weeks after repotting slender-leaved 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.