Repotting guide

When & how to repot Paulownia tomentosa (Paulownia tomentosa)

Also called Foxglove Tree, Empress Tree, Princess Tree.

More about paulownia tomentosa

About Paulownia tomentosa

Paulownia tomentosa · also called Foxglove Tree, Empress Tree · flowering

An extremely fast-growing tree prized for enormous, fuzzy heart-shaped leaves and upright panicles of fragrant, foxglove-like lilac flowers that open before the foliage in spring. Often pollarded for giant decorative leaves. Note it is highly invasive in parts of North America, so check local guidance before planting.

Mature size: Around 8-15 m tall and 8-12 m wide if left unpruned; pollarded plants are kept to 2-4 m as foliage features.

Watch for — Suckering and brittle wood: Vigorous roots can throw up suckers, and the soft, fast-grown timber breaks readily in storms. Remove suckers promptly and prune for sound structure.

How to tell paulownia tomentosa needs repotting

Repotting on a calendar is less reliable than reading the plant. For paulownia tomentosa, 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 paulownia tomentosa 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 paulownia tomentosa

Every 2–3 years; top-dress in the in-between years. Paulownia tomentosa's growth habit — exceptionally fast-growing deciduous tree with a broad, spreading, rounded crown; can put on 2-4 m in a single year when young. often coppiced or pollarded to control size and enlarge the leaves. — sets the pace. An extremely fast-growing tree prized for enormous, fuzzy heart-shaped leaves and upright panicles of fragrant, foxglove-like lilac flowers that open before the foliage in spring. Often pollarded for giant decorative leaves. Note it is highly invasive in parts of North America, so check local guidance before planting.

What size pot to step paulownia tomentosa up to

Move up exactly one pot size. A heavy paulownia tomentosa 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 paulownia tomentosa

Early spring, just as new growth restarts, is the ideal window for paulownia tomentosa. 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 paulownia tomentosa

Consider top-dressing first. If paulownia tomentosa 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 deep, fertile, free-draining loam 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 paulownia tomentosa in the same spot and light — moving and repotting at once is what makes it drop leaves.

Aftercare

Leave paulownia tomentosa 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 paulownia tomentosa

Paulownia tomentosa wants deep, fertile, free-draining loam. Tolerates a wide pH range and many soils, but grows fastest in rich, moist, well-drained ground. Dislikes heavy waterlogged clay and shallow, drought-prone sites. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.

Repotting paulownia tomentosa — frequently asked questions

How often should you repot paulownia tomentosa?

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

What size pot does paulownia tomentosa need?

When is the best time of year to repot paulownia tomentosa?

Should you top-dress or fully repot paulownia tomentosa?

For a big, heavy paulownia tomentosa, 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 paulownia tomentosa after repotting?

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