Gladiolus
Gladiolus x hortulanus · Popular
Tall, one-sided spikes of large, ruffled flowers in almost every colour. The corms are planted in spring and lifted in autumn in cold climates.
- Size
- 4 ft tall, 6 in wide
- Zones
- 8 to 10
- Light
- Full sun
- Flowers
- Mid July to early September
- Pets
- Toxic (mild)
- Job in a bed
- Accent
A bed built around gladiolus
The planner designed this bed around gladiolus when this page was made: a 12 × 6 ft (3.7 × 1.8 m) English border in zone 8, full sun. It chose the other plants from the 872 that suit those conditions, and says below why gladiolus stands where it does.
The plants
- 1 Cottage pinks × 8, pink
- 2 Leadwort × 13, blue
- 3 Little bluestem 'The Blues' × 3, tan
- 4 Stiff goldenrod × 5, yellow
- 5 Dwarf English boxwood × 1, dark green leaves
- 6 English lavender 'Hidcote' × 3, purple
- 7 Gladiolus × 4, red
- 8 Schubert's allium × 2, pink
Why this plant
- The only red.
Why here
- Anchors a back corner. At 4 ft it is the tallest plant here, and the tallest close the ends of the bed, where they stand in front of nothing.
- A step in the back row. Next to little bluestem 'The Blues' (3 ft) and dwarf English boxwood (2½ ft): no two neighbours there are the same height, so the back steps up and down like a skyline.
- 4 plants in 2 places. An accent is a punctuation mark: the repeat along the bed gives it rhythm.
Why now
- In flower for 9 weeks. From mid July to early September.
- Part of the bed's peak. With leadwort, little bluestem 'The Blues' and stiff goldenrod in mid August: 4 kinds at once. No week has more.
Planned as an English border: 6 of the 7 groups (86%) are drifts, longer along the bed than they are deep. Low plants run along 95% of the front edge: leadwort and cottage pinks. Cool colours (pink, blue and purple) with yellow and red as the warm notes, and tan to calm things between them.
The planner's own design check: 11 Excellent, 5 Good, 1 Satisfactory. It flags one thing to watch: Nothing on this plan is highly poisonous or an aggressive spreader.
Open this bed in the planner Change its size, the sun or the style, move plants about, or swap one for another.
Where gladiolus goes in a border
At 4 ft it belongs at the back of a bed. In the planner's ten height classes it is moderately tall (3 to 4 ft).
Its job: accent. An upright plant used singly, like a punctuation mark, and repeated at intervals to give the bed rhythm.
Stiff and showy, it is easier to use in a cutting row than in a border. For the garden, plant in groups of ten among bushy perennials that hide the stakes.
- Cut flowers
- Vertical accents in summer
- Planting in succession for a long season
What to plant with gladiolus
Plants recorded as good partners for it, and what each pairing does:
- Dahlia: purple against yellow, opposite each other on the colour wheel, if you choose those colours, in flower together for nine weeks.
- Canna: purple against yellow, opposite each other on the colour wheel, if you choose those colours, in flower together for nine weeks; bold leaves against its medium ones.
- Shasta daisy 'Becky': in flower together for nine weeks, from mid July.
Questions about gladiolus
Does gladiolus need sun or shade?
Gladiolus grows in full sun (6 or more hours of direct sun a day).
It wants ordinary well-drained soil, rich in organic matter, and a good soak in dry spells.
What zones does gladiolus grow in?
USDA zones 8 to 10. It is hardy to zone 8, which means it survives winter nights down to about 20 °F (−7 °C).
Gardening in Canada? Use the USDA zone for your town: Canada's own zone map uses different numbers.
When does gladiolus flower in my zone?
In zone 5 it flowers mid July to early September. As a summer flower it moves about half a week for every zone: earlier where it is warmer.
| Zone 8 | Early July to early September |
|---|---|
| Zone 9 | Late June to early 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 gladiolus be planted?
5 in (12 cm) apart, from the middle of one plant to the middle of the next. That is a little closer than its full width of 6 in (15 cm), so a group knits into one patch.
It grows 4 ft (120 cm) tall. Give it the full distance from anything taller, or it will lean out towards the light.
How many gladiolus plants do I need?
At 5 in apart, set out in staggered rows:
- 74 to fill 10 square feet (about 1 m²)
- 26 for a single row 10 ft (3 m) long
- 238 to fill a 4 × 8 ft bed on its own
In a mixed border, plant it as one at a time, repeated along the bed at intervals; a slender one reads better as a clump of three.
In the bed above, the planner used four in two groups.
Is gladiolus poisonous to dogs and cats?
Yes: mild toxicity to dogs, cats and horses. Can cause drooling, vomiting and diarrhoea in pets if eaten. The corms are the most poisonous part.
Rated from the ASPCA. Where references disagree, the more cautious rating is used.
Is there a pet-safe plant like gladiolus?
These come closest to doing what gladiolus does, and no toxicity is recorded for them:
- Blue vervain: the same job in a bed and the same flowering time; 11 in wider, blue, not red.
- Red hot poker: the same job in a bed and the same colour; 8 in shorter, 19 in wider.
- Prairie blazing star: the same job in a bed and the same flowering time; 11 in wider, purple, not red.
Matched the way the planner's Swap button matches plants: the same job in a bed, then size, then flowering time.
What can I plant to hide gladiolus's leaves after it flowers?
A bulb's leaves have to be left to yellow for about six weeks after flowering, to feed next year's flowers. Plant it among perennials that come up late and spread wide, and they grow over the leaves as they fade:
- Blue false indigo: 4 ft tall and 4 ft wide, in flower late May to mid June.
- Peony: 3 ft tall and 3 ft wide, in flower late May to late June.
- Daylily: 2½ ft tall and 24 in wide, in flower late June to early August.
What does gladiolus look like in winter?
Gladiolus is underground: it dies back after flowering and waits as a bulb until spring. Mark where it is, so a fork does not find it first.
More Gladiolus
- Hardy gladiolus Gladiolus communis subsp. byzantinus
In these guides
Every fact on record
- Type
- Bulb
- Size
- 4 ft (120 cm) tall, 6 in (15 cm) wide
- Plant
- 5 in (12 cm) apart
- Height class
- Moderately tall (3 to 4 ft)
- Place in the bed
- Back
- Flowers
- Mid July to early September; upright spires; red, pink, orange, yellow, purple, white
- Leaves
- Medium texture, herbaceous; green
- Shape
- Upright, clumping
- Hardy in
- USDA zones 8 to 10
- Light
- Full sun
- Soil
- Rich, well-drained
- Water
- Moderate
- Feeding
- Moderate, in spring
Checked against 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.