What soil does Hybrid cardinal flower grow in?

It tolerates these soils: average garden soil, clay.

Is Hybrid cardinal flower hardy?

Hardy down to -23 °C (USDA zone 6, RHS H7). It gets through winter everywhere at lower altitudes, but may not survive unprotected in a mountain garden.

When does Hybrid cardinal flower flower?

Flowering: July–October, red, pink, purple, blue.

How much water does Hybrid cardinal flower need?

Water need: high. Drought tolerance: low.

Hybrid cardinal flower

Lobelia × speciosa

Hybrid cardinal flower (Lobelia × speciosa) is a perennial. Light: full sun, part shade. Hardy down to -23 °C. Drought tolerance: low. Toxic to children.

Illustration of Hybrid cardinal flower — An illustration of the typical shape of the mature plant, not a photo.

What it's good for, and what it isn't

An upright perennial with dense flower spikes in red, pink, purple or blue from midsummer into autumn, and many forms have bronze foliage too. It belongs in moist or even wet soil, by a pond or in a regularly watered bed, and fails quickly if it dries out. It is short-lived: it does not always come through cold, wet winters, so mulch the crown for winter and divide it every few years in spring.

Watch out for

In Central Europe it is often lost in cold, wet winters, especially without mulch and in heavy soil that stays wet in winter, so expect to replace it or renew it by division every few years. Slugs can damage the young shoots, and it scorches in hot sun without watering.

Key facts

Light: Full sun, Part shade
Water need: High
Care: Medium
Size after 10 years: 80 cm × 35 cm
Hardiness: down to -23 °C
Foliage: Deciduous
Flowering: J F M A M J J A S O N D July–October, red, pink, purple, blue

Group	Perennial
Light	Full sun, Part shade
Size after 10 years	80 cm × 35 cm
Ultimate size	0.5–1 m × 20–50 cm
Hardiness	down to -23 °C (USDA 6, RHS H7)
Soil	Average garden soil, Clay
Foliage	Deciduous
Flowering	July–October, red, pink, purple, blue
Water need	High
Drought tolerance	Low
Maintenance	Medium
Root aggressiveness	Low
Suckering	no data
Spreading	Low
Distance from buildings	no data
Distance from paving	no data
Litter	not typical
Planting distance	35 cm
For dogs	Toxic (uncertain)
For cats	Toxic (uncertain)
For children	Toxic
Typical price	no data

Toxicity data is for information only. If your pet or child has eaten a plant, contact a vet or a doctor.

Frequently asked questions

Data updated: October 8, 2026 · How our data is made

Appears in these lists

Perennials for part shade Perennials for full sun Perennials for clay soil Perennials for pollinators Plants for containers

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