Repotting guide

When & how to repot Mysore trumpetvine (Thunbergia mysorensis)

Also called Mysore trumpetvine, Mysore clock vine, Indian clock vine, Brick and butter vine.

More about mysore trumpetvine

About Mysore trumpetvine

Thunbergia mysorensis · also called Mysore trumpetvine, Mysore clock vine · tropical

Mysore trumpetvine is a spectacular evergreen woody climber from the Western Ghats of southern India, producing dramatic pendulous racemes of large chocolate-red and yellow tubular flowers year-round in warm climates. Best grown in a heated glasshouse or tropical garden. Thunbergia is not listed as toxic by the ASPCA and is considered safe around pets.

Mature size: 4–6 m (13–20 ft), potentially to 20 m (65 ft) in ideal tropical conditions

How to tell mysore trumpetvine needs repotting

Repotting on a calendar is less reliable than reading the plant. For mysore trumpetvine, 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 mysore trumpetvine 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 mysore trumpetvine

Every 2–3 years; top-dress in the in-between years. Mysore trumpetvine's growth habit — vigorous evergreen woody twining climber — sets the pace. Mysore trumpetvine is a spectacular evergreen woody climber from the Western Ghats of southern India, producing dramatic pendulous racemes of large chocolate-red and yellow tubular flowers year-round in warm climates. Best grown in a heated glasshouse or tropical garden. Thunbergia is not listed as toxic by the ASPCA and is considered safe around pets.

What size pot to step mysore trumpetvine up to

Move up exactly one pot size. A heavy mysore trumpetvine 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 mysore trumpetvine

Early spring, just as new growth restarts, is the ideal window for mysore trumpetvine. 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 mysore trumpetvine

Consider top-dressing first. If mysore trumpetvine 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 loam-based, free-draining potting compost 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 mysore trumpetvine in the same spot and light — moving and repotting at once is what makes it drop leaves.

Aftercare

Leave mysore trumpetvine 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 mysore trumpetvine

Mysore trumpetvine wants loam-based, free-draining potting compost. Under glass, use a peat-free loam-based compost (e.g., John Innes No. 3) with added perlite for drainage. Outdoors in the ground, plant in humus-rich, moisture-retentive but free-draining soil. Good drainage is critical; waterlogged roots cause rapid decline. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.

Repotting mysore trumpetvine — frequently asked questions

How often should you repot mysore trumpetvine?

Every 2–3 years; top-dress in the in-between years for mysore trumpetvine. Fully repot mysore trumpetvine 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 loam-based, free-draining potting compost. It is heavy and hates being moved, and a vastly oversized pot holds water against the roots and rots them.

What size pot does mysore trumpetvine need?

When is the best time of year to repot mysore trumpetvine?

Should you top-dress or fully repot mysore trumpetvine?

For a big, heavy mysore trumpetvine, 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 mysore trumpetvine after repotting?

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