Repotting guide

When & how to repot Begonia grandis subsp. evansiana (Begonia grandis subsp. evansiana)

Also called Evans's hardy begonia, hardy chinese begonia.

More about begonia grandis subsp. evansiana

About Begonia grandis subsp. evansiana

Begonia grandis subsp. evansiana · also called Evans's hardy begonia, hardy chinese begonia · flowering

Begonia grandis subsp. evansiana is the hardiest begonia, a tuberous perennial with angel-wing leaves backed in red and airy sprays of pink (or white) flowers from midsummer to autumn. Holding an RHS Award of Garden Merit, it thrives in partial shade and humus-rich, well-drained soil, dies back in winter, and returns from underground tubers and bulbils.

Mature size: Around 40-60 cm tall and 30-45 cm wide.

How to tell begonia grandis subsp. evansiana needs repotting

Repotting on a calendar is less reliable than reading the plant. For begonia grandis subsp. evansiana, watch for these signs:

Flowering has tailed off year on year and the clump has become congested and overcrowded.
Lots of leaf and few flowers — a classic sign that begonia grandis subsp. evansiana bulbs or tubers need lifting and dividing.
Bulbs visibly bursting the pot or pushing each other to the surface.
It is the natural dormancy window (foliage yellowed and died back) — the only safe time to lift and split.

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 begonia grandis subsp. evansiana

Lift and divide every 3–4 years once clumps congest. Rather than a true repot, begonia grandis subsp. evansiana is lifted and divided once the clump congests and flowering drops off. Upright, branching tuberous herbaceous perennial that emerges late in spring, flowers from midsummer, then dies back to dormant tubers; spreads modestly by tubers and aerial bulbils..

What size pot to step begonia grandis subsp. evansiana up to

Pot size matters less than depth and spacing here. When you replant begonia grandis subsp. evansiana, set the bulbs or tubers at the correct depth (a rough guide: two to three times their own height of soil over the top) and space them so they are not touching. A wide, shallow pot suits a clump better than a tall narrow one.

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 begonia grandis subsp. evansiana

The only safe window is dormancy: wait until the foliage has yellowed and died back naturally, lift and divide then, and replant before or at the start of the next growing season. Disturbing begonia grandis subsp. evansiana in full growth or flower sets it back badly.

Step-by-step: repotting begonia grandis subsp. evansiana

Wait for dormancy. Let begonia grandis subsp. evansiana foliage yellow and die back completely. Lifting while it is in growth wastes the energy it is storing for next year.
Lift carefully. Loosen the soil well away from the bulbs/tubers with a fork and ease the whole clump out without spearing them.
Separate the offsets. Gently pull the clump apart into individual bulbs or tubers. Keep only firm, healthy, blemish-free ones.
Replant at the right depth. Reset them in fresh fertile, humus-rich, well-drained, neutral to acid soil at the correct depth and spacing — not touching — so each has room to bulk up.
Water in and rest. Water once to settle them, then keep on the dry side until growth resumes. Do not feed until leaves are actively growing.

Aftercare

After replanting begonia grandis subsp. evansiana, keep the soil barely moist — not wet — until shoots appear; bulbs and tubers rot in cold, saturated soil. Once leaves are growing strongly, resume normal watering. Hold off feeding until the plant is in active growth again.

The right soil mix for begonia grandis subsp. evansiana

Begonia grandis subsp. evansiana wants fertile, humus-rich, well-drained, neutral to acid soil. Prefers a moist but free-draining loamy or sandy soil enriched with organic matter. Good drainage is essential for the tubers to overwinter; heavy, waterlogged clay encourages rot. A leafy mulch helps retain moisture and protects the crown in cold zones. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.

Repotting begonia grandis subsp. evansiana — frequently asked questions

How often should you repot begonia grandis subsp. evansiana?

Lift and divide every 3–4 years once clumps congest for begonia grandis subsp. evansiana. Begonia grandis subsp. evansiana is lifted and divided, not "repotted". Every 3–4 years, once the foliage has died back and it is dormant, lift the clump, separate the offsets, and replant at the correct depth in fertile, humus-rich, well-drained, neutral to acid soil. Crowding, not pot size, is what reduces flowering over time.

What size pot does begonia grandis subsp. evansiana need?

When is the best time of year to repot begonia grandis subsp. evansiana?

Do you "repot" begonia grandis subsp. evansiana, or lift and divide it?

You lift and divide it. Begonia grandis subsp. evansiana grows from bulbs or tubers, so instead of repotting you wait for dormancy, lift the congested clump, separate the healthy offsets, and replant them at the right depth and spacing. Doing this every 3–4 years restores flowering.

Should you fertilise begonia grandis subsp. evansiana after repotting?

Hold off feeding begonia grandis subsp. evansiana until it is in active growth again. Fresh soil already carries enough nutrients to get it re-established, and feeding disturbed roots too soon does more harm than good.