Repotting guide

When & how to repot Toothed Fly Bush (Roridula dentata)

Also called toothed fly bush.

More about toothed fly bush

About Toothed Fly Bush

Roridula dentata · also called toothed fly bush · houseplant

Roridula dentata is a resinous South African carnivorous shrub distinguished from R. gorgonias by its toothed leaf margins and slightly larger stature. Like its relative, it traps insects on sticky resin and relies on Pameridea bugs for digestion. Demanding in cultivation — strictly mineral-free water and high light are non-negotiable.

Mature size: Up to 1.5 m (5 ft) in habitat; 40–80 cm (16–32 in) in cultivation

Watch for — Root and stem rot: Waterlogging or stagnant standing water causes basal rot on the woody stem. Ensure the pot has drainage holes and the tray water is refreshed rather than left static for more than a day or two.

How to tell toothed fly bush needs repotting

Repotting on a calendar is less reliable than reading the plant. For toothed fly bush, watch for these signs:

Thick roots out of the drainage holes, or circling the surface and lifting the plant.
The pot dries out unusually fast and toothed fly bush wilts between waterings it used to shrug off.
The plant is visibly top-heavy and tips over easily.
Stalled growth and small new leaves over a full season — though with a big specimen, top-dressing is often the better first response before a full 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 toothed fly bush

Every 2–3 years; top-dress in the in-between years. Toothed Fly Bush's growth habit — upright branching woody shrub with toothed, resin-coated leaves — sets the pace. Roridula dentata is a resinous South African carnivorous shrub distinguished from R. gorgonias by its toothed leaf margins and slightly larger stature. Like its relative, it traps insects on sticky resin and relies on Pameridea bugs for digestion. Demanding in cultivation — strictly mineral-free water and high light are non-negotiable.

What size pot to step toothed fly bush up to

Move up exactly one pot size. A heavy toothed fly bush dropped into a vastly bigger pot sits in a reservoir of wet soil its roots cannot reach, which rots them and destabilises the plant. In the years between repots, lift off and replace the top 3–5 cm of soil (top-dressing) instead — it refreshes nutrients without the shock of a full repot.

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 toothed fly bush

Early spring, just as new growth restarts, is the ideal window for toothed fly bush. 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 toothed fly bush

Consider top-dressing first. If toothed fly bush is not badly root-bound, scrape off and replace the top 3–5 cm of soil instead — far less shock for a big plant that hates moving.
Get help and one size up. For a full repot, choose a pot just one size larger. A heavy plant needs two people and a stable, free-draining pot.
Ease it out on its side. Lay the plant down, slide the pot off, and gently loosen the outer roots. Do not bare-root a mature specimen.
Repot at the same depth. Add fresh nutrient-poor acidic mix: 2 parts peat or coco-coir to 1 part perlite beneath and around the rootball, keeping the original soil line. Firm it so the trunk is stable and upright.
Water and leave it put. Water thoroughly, then leave toothed fly bush in the same spot and light — moving and repotting at once is what makes it drop leaves.

Aftercare

Leave toothed fly bush in exactly the same spot and light it was in before — moving and repotting at the same time is what makes a big specimen drop leaves. Water it in well, then let the top of the soil dry before watering again so the larger volume of fresh soil does not stay sodden. Do not fertilise for about 4 weeks — fresh mix already carries nutrients and feeding freshly disturbed roots scorches them.

The right soil mix for toothed fly bush

Toothed Fly Bush wants nutrient-poor acidic mix: 2 parts peat or coco-coir to 1 part perlite. Neutral to acidic pH (4.5–5.5). No added fertiliser, compost, or bark. Roridula in the wild grows in nutrient-depleted sandstone fynbos soils; rich substrates stimulate rapid rotting of the woody base. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.

Repotting toothed fly bush — frequently asked questions

How often should you repot toothed fly bush?

Every 2–3 years; top-dress in the in-between years for toothed fly bush. Fully repot toothed fly bush only every 2–3 years; in the in-between years just top-dress the top 3–5 cm of soil. Step up one pot size in spring with nutrient-poor acidic mix: 2 parts peat or coco-coir to 1 part perlite. It is heavy and hates being moved, and a vastly oversized pot holds water against the roots and rots them.

What size pot does toothed fly bush need?

When is the best time of year to repot toothed fly bush?

Should you top-dress or fully repot toothed fly bush?

For a big, heavy toothed fly bush, top-dressing — replacing the top 3–5 cm of soil — is the gentler option most years, with a full repot only every 2–3 years. A mature specimen sulks and drops leaves when fully repotted, so do it as rarely as the roots allow.

Should you fertilise toothed fly bush after repotting?

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