Repotting guide

When & how to repot Stomandra Cape Primrose (Streptocarpus stomandrus)

Also called Stomandra Cape Primrose, Cape Primrose.

More about stomandra cape primrose

About Stomandra Cape Primrose

Streptocarpus stomandrus · also called Stomandra Cape Primrose, Cape Primrose · houseplant

Streptocarpus stomandrus is a caulescent (stemmed) species native to the Nguru Mountains of the Morogoro District in Tanzania, where it grows in shaded, moist highland conditions. Unlike the familiar rosulate Cape Primroses, it forms a branching, semi-erect herb to about 25 cm tall with opposite, ovate-elliptic, softly hairy leaves and small clusters of tubular flowers on axillary peduncles. It requires consistently warm, humid conditions and bright filtered light, and is more sensitive to cold and drought than most cultivated Streptocarpus. According to the ASPCA, the Streptocarpus genus is non-toxic to cats, dogs, and horses.

Mature size: Stems to approximately 20–25 cm tall; plant spreads to about 20 cm wide.

How to tell stomandra cape primrose needs repotting

Repotting on a calendar is less reliable than reading the plant. For stomandra cape primrose, 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 stomandra cape primrose 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 stomandra cape primrose

Every 2–3 years; top-dress in the in-between years. Stomandra Cape Primrose's growth habit — caulescent, semi-erect to decumbent perennial herb with a woody base and branching stems bearing opposite pairs of leaves. — sets the pace. Streptocarpus stomandrus is a caulescent (stemmed) species native to the Nguru Mountains of the Morogoro District in Tanzania, where it grows in shaded, moist highland conditions. Unlike the familiar rosulate Cape Primroses, it forms a branching, semi-erect herb to about 25 cm tall with opposite, ovate-elliptic, softly hairy leaves and small clusters of tubular flowers on axillary peduncles. It requires consistently warm, humid conditions and bright filtered light, and is more sensitive to cold and drought than most cultivated Streptocarpus. According to the ASPCA, the Streptocarpus genus is non-toxic to cats, dogs, and horses.

What size pot to step stomandra cape primrose up to

Move up exactly one pot size. A heavy stomandra cape primrose 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 stomandra cape primrose

Early spring, just as new growth restarts, is the ideal window for stomandra cape primrose. 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 stomandra cape primrose

Consider top-dressing first. If stomandra cape primrose 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 humus-rich, well-draining gesneriad mix 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 stomandra cape primrose in the same spot and light — moving and repotting at once is what makes it drop leaves.

Aftercare

Leave stomandra cape primrose 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 stomandra cape primrose

Stomandra Cape Primrose wants humus-rich, well-draining gesneriad mix. A blend of coir, perlite, and fine bark replicates the well-aerated, organic highland soils of its native habitat; avoid heavy, waterlogged composts. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.

Repotting stomandra cape primrose — frequently asked questions

How often should you repot stomandra cape primrose?

Every 2–3 years; top-dress in the in-between years for stomandra cape primrose. Fully repot stomandra cape primrose 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 humus-rich, well-draining gesneriad mix. It is heavy and hates being moved, and a vastly oversized pot holds water against the roots and rots them.

What size pot does stomandra cape primrose need?

When is the best time of year to repot stomandra cape primrose?

Should you top-dress or fully repot stomandra cape primrose?

For a big, heavy stomandra cape primrose, 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 stomandra cape primrose after repotting?

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