Hardy begonia
Begonia grandis · Begoniaceae
The only begonia hardy in cold gardens: angel-wing leaves, red beneath, and drooping sprays of pink flowers from late summer to frost.
- Size
- 24 in tall, 18 in wide
- Zones
- 6 to 9
- Light
- Part shade to shade
- Flowers
- Mid August to late September
- Pets
- Toxic (mild)
- Job in a bed
- Drift
A bed built around hardy begonia
The planner designed this bed around hardy begonia when this page was made: a 12 × 6 ft (3.7 × 1.8 m) cottage garden in zone 6, part shade. It chose the other plants from the 513 that suit those conditions, and says below why hardy begonia stands where it does.
The plants
- 1 Hardy begonia × 3, pink
- 2 Creeping phlox 'Sherwood Purple' × 5, purple
- 3 Moor grass 'Greenlee' × 6, tan
- 4 Foxglove × 4, white
- 5 White snakeroot 'Chocolate' × 3, white
- 6 Inkberry 'Gem Box' × 1, dark green leaves
- 7 Trout lily 'Pagoda' × 12, yellow
- 8 Giant snowdrop × 12, white
Why this plant
- The only airy sprays. The others are dense clusters, spires and bells. Shape reads at a distance, where colours blur.
- The only pink.
Why here
- In the middle. At 24 in it is the step between moor grass 'Greenlee' (12 in) in front and inkberry 'Gem Box' (2½ ft) behind: each is seen over the one before.
- 3 plants in one group. Massed, one kind reads as a single shape. Scattered, it would look spotty.
- Bold leaf against fine. Inkberry 'Gem Box' is beside it: the strongest contrast of leaf there is.
Why now
- In flower for 7 weeks. From mid August to late September.
- Fills a gap. For two of those weeks nothing else on the plan is in flower.
Planned as a cottage garden: 22 of the 22 plants (100%), bulbs aside, stand alone or in groups of no more than five, small enough for the kinds to mingle. Cool colours (pink and purple) with yellow as the warm note, and tan and white to calm things between them. White snakeroot 'Chocolate' and foxglove anchor the back corners of the bed: the tallest plants on the plan stand there.
The planner's own design check: 13 Excellent, 3 Good, 1 Satisfactory.
Open this bed in the planner Change its size, the sun or the style, move plants about, or swap one for another.
Where hardy begonia goes in a border
At 24 in it belongs in the middle of a bed. In the planner's ten height classes it is medium short (18 to 24 in).
Its job: drift. Planted in a small group of three or five, and repeated further along in the other number.
It flowers in shade at the end of summer, when shade gardens have little else. The leaves glow red when low sun shines through them, so plant it where evening light comes from behind. It is late to emerge in spring.
- Late-summer flowers for shade
- Woodland gardens
- A partner for hostas and ferns
What to plant with hardy begonia
Plants recorded as good partners for it, and what each pairing does:
- Hosta: its green leaves are a setting for the flowers, before and after; spires rising out of its mound; happy in the same moist soil.
- Japanese painted fern: its silver leaves are a setting for the flowers, before and after; fine leaves against its bold ones; happy in the same moist soil.
- Toad lily: in flower together for three weeks, from mid September; medium leaves against its bold ones; happy in the same moist soil.
Questions about hardy begonia
Does hardy begonia need sun or shade?
Hardy begonia grows in part shade (2 to 4 hours of sun, mostly in the morning) and shade (less than 2 hours of direct sun, or bright dappled light). It is one of the few that also put up with deep shade.
It wants soil that stays evenly moist, rich in organic matter, and a good soak in dry spells.
What zones does hardy begonia grow in?
USDA zones 6 to 9. It is hardy to zone 6, which means it survives winter nights down to about 0 °F (−18 °C).
Gardening in Canada? Use the USDA zone for your town: Canada's own zone map uses different numbers.
When does hardy begonia flower in my zone?
In zone 5 it flowers mid August to late September. As a summer flower it moves about half a week for every zone: earlier where it is warmer.
| Zone 6 | Mid August to late September |
|---|---|
| Zone 7 | Early August to late September |
| Zone 8 | Early August to late September |
| Zone 9 | Early August to late September |
Worked out from Hopkins' bioclimatic law: spring arrives about four days later for each degree of latitude north, and one zone is roughly two degrees. A warm spring or a cold one moves any garden two weeks either way.
How far apart should hardy begonia be planted?
18 in (45 cm) apart, from the middle of one plant to the middle of the next. That is about its full width, so each plant keeps its own outline.
It grows 24 in (60 cm) tall. Give it the full distance from anything taller, or it will lean out towards the light.
How many hardy begonia plants do I need?
At 18 in apart, set out in staggered rows:
- 5 to fill 10 square feet (about 1 m²)
- 7 for a single row 10 ft (3 m) long
- 17 to fill a 4 × 8 ft bed on its own
In a mixed border, plant it as a group of three or five, with a second group further along in the other number.
In the bed above, the planner used three in one group.
Is hardy begonia poisonous to dogs and cats?
Yes: mild toxicity to dogs, cats and horses. Can cause burning of the mouth and vomiting in pets if chewed. The roots are the most poisonous part.
Rated from NC State Extension and the ASPCA. Where references disagree, the more cautious rating is used.
Is there a pet-safe plant like hardy begonia?
These come closest to doing what hardy begonia does, and no toxicity is recorded for them:
- Rose turtlehead: the same job in a bed, the same flowering time and the same colour; 8 in taller, medium leaves, not bold.
- White wood aster: the same job in a bed, the same size and the same flowering time; white, not pink, medium leaves, not bold.
- Wild geranium: the same job in a bed and the same colour; 4 in shorter, flowers early May to late May.
Matched the way the planner's Swap button matches plants: the same job in a bed, then size, then flowering time.
Do deer eat hardy begonia?
They may. NC State does not list it as resistant to deer or rabbits. Where they visit, protect it, or plant it among ones they avoid.
Will hardy begonia spread?
It seeds itself about; the risk of it taking over is moderate. Spreads by tiny bulbils that drop from the leaf joints and sprout nearby. Unwanted plants pull out easily.
What does hardy begonia look like in winter?
Hardy begonia dies down to the ground and there is nothing to see until spring. The old stems can be cut in autumn, or left until spring as shelter for overwintering insects.
Is hardy begonia good for bees and butterflies?
Hardy begonia is visited by pollinators.
In these guides
- Plants for deep shade
- Plants that grow near black walnut
- Garden plants toxic to cats
- Garden plants toxic to dogs
- Plants that flower in fall
Every fact on record
- Type
- Perennial
- Size
- 24 in (60 cm) tall, 18 in (45 cm) wide
- Plant
- 18 in (45 cm) apart
- Height class
- Medium short (18 to 24 in)
- Place in the bed
- Middle
- Flowers
- Mid August to late September; airy sprays; pink
- Leaves
- Bold texture, herbaceous; green
- Shape
- Mounding, self-seeding
- Hardy in
- USDA zones 6 to 9
- Light
- Part shade, shade
- Soil
- Rich, evenly moist
- Water
- Moderate
- Feeding
- Light, in spring
- Family
- Begoniaceae
- Comes from
- Southern China, Japan
- Attracts
- Pollinators
- Stands up to
- Deep shade, black walnut
Checked against NC State Extension and ASPCA poison lists. Flowering times are for zone 5: later in colder zones, earlier in warmer ones. Toxicity and spread information is a general gardening guide, not veterinary or medical advice, and invasive status varies by region. If a person or pet eats a plant, contact poison control or a vet. Check your local invasive species list before planting anything with a spread warning.