Repotting guide

When & how to repot Fly Bush (Roridula gorgonias)

Also called fly bush, fly catcher bush.

More about fly bush

About Fly Bush

Roridula gorgonias · also called fly bush, fly catcher bush · houseplant

Roridula gorgonias is a resinous South African carnivorous shrub that traps insects on sticky leaves but relies on symbiotic assassin bugs (Pameridea) to digest prey. Grow in bright light with mineral-free water, lean acidic soil, and high humidity. Challenging to cultivate indoors; best for specialist collectors.

Mature size: Up to 1 m (3 ft) tall in native habitat; typically 30–60 cm (12–24 in) in cultivation

Watch for — Root rot: Overwatering combined with poor drainage or stagnant tray water causes root rot on the woody rootstock. Ensure the mix drains freely and refresh the tray water regularly rather than leaving it stagnant.

How to tell fly bush needs repotting

Repotting on a calendar is less reliable than reading the plant. For 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 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 fly bush

Every 2–3 years; top-dress in the in-between years. Fly Bush's growth habit — upright woody shrub with resin-coated linear leaves arranged spirally on branching stems — sets the pace. Roridula gorgonias is a resinous South African carnivorous shrub that traps insects on sticky leaves but relies on symbiotic assassin bugs (Pameridea) to digest prey. Grow in bright light with mineral-free water, lean acidic soil, and high humidity. Challenging to cultivate indoors; best for specialist collectors.

What size pot to step fly bush up to

Move up exactly one pot size. A heavy 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 fly bush

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

Consider top-dressing first. If 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 lean, mineral-free mix: 2:1 peat or coco-coir to sharp perlite or coarse river sand 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 fly bush in the same spot and light — moving and repotting at once is what makes it drop leaves.

Aftercare

Leave 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 fly bush

Fly Bush wants lean, mineral-free mix: 2:1 peat or coco-coir to sharp perlite or coarse river sand. Must be nutrient-poor and acidic (pH 4.5–5.5). Never add fertiliser to the substrate. Pure sphagnum moss alone tends to retain too much moisture and can rot the woody stems; a peat-perlite mix is more reliable. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.

Repotting fly bush — frequently asked questions

How often should you repot fly bush?

Every 2–3 years; top-dress in the in-between years for fly bush. Fully repot 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 lean, mineral-free mix: 2:1 peat or coco-coir to sharp perlite or coarse river sand. It is heavy and hates being moved, and a vastly oversized pot holds water against the roots and rots them.

What size pot does fly bush need?

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

Should you top-dress or fully repot fly bush?

For a big, heavy 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 fly bush after repotting?

Not immediately. Wait about 4 weeks after repotting 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.