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Red valerian

Red valerian

Centranthus ruber
Red valerian is a short-lived Mediterranean perennial native to rocky coastal and limestone habitats from Portugal and Morocco east through southern Europe to European Turkey (Wikipedia). Its dense crimson, pink, or white flower heads bloom from late spring through autumn and attract bees and long-tongued butterflies freely, making it a valued pollinator border plant. It thrives in poor, alkaline, freely drained soils and tolerates dry walls and coastal exposure with minimal care. The honest catch is its prolific self-seeding: left unchecked it colonises walls, gravel, and neighbouring beds aggressively, and it is a regulated invasive (NEMBA 1b, compulsory control) in South Africa's Western Cape and an environmental weed in California and Australia (Wikipedia) — deadhead promptly or the plant manages the garden, not the other way round.
Climate fit: narrow (39/100)
Border
Pollinator
Container
Light
Full sun / Part sun
Water
Low water
Mature size
24-36" tall · 18" apart
Hardy in zones
5a-9b
very cold to frosty winters
Native in Illinois
No

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Self-fertile and pollinated by a wide range of bees and long-tongued butterflies attracted to the nectar spur (Wikipedia: pollinated by both bees and butterflies).

Cold hardiness

These values are location-based: this location's current hardiness is the baseline, and the 2050 value is a projected future climate for this same location.
Now
Zone 6b
Plotwright
USDA Zone 6b
-5°F to 0°F
Well-suited
Zone 7a
Plotwright
0°F to 5°F
Well-suited
In plain terms: This location has cold winters. Its winters are projected to keep warming through 2050.
Well-suited today and still thriving in 2050.

Heat tolerance

Heat tolerance values are location-based too: heat days today are observed at this site, and the 2050 value projects this same location under a future climate.
Loading AHS heat-zone data for this location...

Similar plants

Browse lateral options with similar roles, light needs, size, or native-range overlap; these are not filtered for a better climate fit.
Platycodon grandiflorus
Balloon flower
Balloon flower is a long-lived East Asian perennial grown for its inflated, balloon-like buds that pop open into wide, five-petalled violet-blue (or white or pink) stars in mid- to late summer — one of the most distinctive bloom shapes in the border. Native to China, Korea, Japan, and the Russian Far East, it is bone-hardy (USDA zones 3a-9b) and largely trouble-free once established. The honest catch is its very late spring emergence: balloon flower is among the last perennials to surface, reappearing in late spring when other beds are already full, and its fleshy tap-like roots resent disturbance — mark it clearly, never move it, and resist the urge to poke around the crown before the shoots appear.
Perennial
Full sun / Part sun
Moderate water
Zones 3a-9b
Climate: moderate
Border
Pollinator
Container
Eucomis comosa
Pineapple lily
Eucomis comosa, the pineapple lily or wine eucomis, is a deciduous summer-growing bulb in the asparagus family (Asparagaceae), endemic to the Eastern Cape and KwaZulu-Natal provinces of South Africa. From a large, often purple bulb it sends up a basal rosette of strap-shaped leaves and a stout flower spike packed with white-to-purple star flowers, crowned by a tuft of leafy bracts that gives it a pineapple-like silhouette in mid-to-late summer. It is a striking focal-point and container subject for borders, prized for its long-lasting bloom. Hardiness is the load-bearing caution: it is frost-tender to only borderline-hardy (RHS H4, roughly USDA 8–10, surviving brief dips near -5 to -10 C in well-drained, sheltered ground), so in colder climates it is grown in pots and lifted or moved under cover for winter, and it resents winter wet. The bulb and foliage contain saponins and can cause mild mouth irritation, drooling, and stomach upset if eaten, so keep it away from pets and children.
Perennial
Full sun / Part sun
Moderate water
Zones 8a-10b
Climate: narrow
Focal point
Container
Border
Pollinator
Aubrieta deltoidea
Aubrieta
Aubrieta (Aubrieta deltoidea) is a low, mat-forming evergreen perennial in the mustard family (Brassicaceae), native to the rocky hillsides of southeastern Europe — primarily Greece, the Aegean Islands, Crete, and adjacent Mediterranean coasts. It is one of the most reliable spring-flowering ground covers for sunny, well-drained spots: cascading sheets of violet to deep pink four-petalled blooms from March through May, attractive to bees and bee flies. The honest catch is that without a hard cut-back immediately after flowering, plants become woody and bare in the centre within two or three years, collapsing from a tight carpet into a tired, gappy mat.
Perennial
Full sun / Part sun
Low water
Zones 4a-9b
Climate: moderate
Border
Filler
Pollinator
Container
Colchicum autumnale
Autumn Crocus
Colchicum autumnale is a corm-forming herbaceous perennial native to lowland grassy meadows across much of Europe, from Portugal and Great Britain east to Ukraine. In autumn it sends up naked goblet-shaped flowers of lilac-pink directly from the bare soil — leaves and seedpods follow in spring and die back by early summer. The honest catch is its extreme toxicity: every part of the plant contains colchicine, a compound lethal to humans and animals, and the broad strap-like spring leaves are routinely mistaken for edible wild garlic — a potentially fatal confusion. Despite the common name, it is not a true crocus (Crocus, Iridaceae) but a member of the Colchicaceae.
Perennial
Full sun / Part sun
Moderate water
Zones 4a-9b
Climate: moderate
Border
Pollinator
Container
Gerbera jamesonii
Barberton daisy
Gerbera jamesonii, the Barberton daisy (also Transvaal daisy), is a tufted evergreen perennial herb in the daisy family (Asteraceae) native to the summer-rainfall grasslands and rocky woodland of north-eastern South Africa and Eswatini. It forms a basal rosette of lobed leaves from which leafless flowering scapes rise, each topped by a single large daisy-style flowerhead in orange-red, yellow, pink, or white. It is the wild ancestor of the thousands of florist gerbera cultivars and earns its place as a long-blooming focal point in borders and patio containers, attractive to bees and other insects. The load-bearing caution is frost-tenderness: RHS rates it H1C, meaning it survives outdoors only in summer or the very mildest, frost-free spots and must be overwintered under glass elsewhere (roughly USDA 9-11). It is non-toxic, with no reported poisoning hazard to people or pets, making it a safe choice where toxicity is a concern.
Perennial
Full sun / Part sun
Moderate water
Zones 9a-11
Climate: narrow
Border
Container
Focal point
Pollinator
Felicia amelloides
Blue daisy bush
Felicia amelloides is an evergreen, woody-based perennial subshrub native to a narrow coastal strip of South Africa's Western and Eastern Cape, where it colonises stabilising sand dunes, sandy flats, and rocky outcrops at 0-1,000 m. In the garden it delivers a near-continuous flush of sky-blue, yellow-centred daisy flowers on neat mounding growth, typically 12-24 inches but capable of reaching about 1 m, making it one of the few true blue-flowered plants for sunny pots and borders. The honest catch is frost-tenderness: it survives only light frost in sharply drained soil and collapses below about 23F (-5C), so outside USDA zones 9-11 it must be overwintered under glass or replaced annually — a real commitment in cool-temperate gardens.
Perennial
Full sun / Part sun
Low water
Zones 9a-11b
Climate: narrow
Border
Container
Pollinator
Filler

Educator packet

Plant packet
Red valerian educator packet
Red valerian is a short-lived Mediterranean perennial native to rocky coastal and limestone habitats from Portugal and Morocco east through southern Europe to European Turkey (Wikipedia). Its dense crimson, pink, or white flower heads bloom from late spring through autumn and attract bees and long-tongued butterflies freely, making it a valued pollinator border plant. It thrives in poor, alkaline, freely drained soils and tolerates dry walls and coastal exposure with minimal care. The honest catch is its prolific self-seeding: left unchecked it colonises walls, gravel, and neighbouring beds aggressively, and it is a regulated invasive (NEMBA 1b, compulsory control) in South Africa's Western Cape and an environmental weed in California and Australia (Wikipedia) — deadhead promptly or the plant manages the garden, not the other way round.
Scientific name
Centranthus ruber
Plant type
perennial
Hardiness
5a-9b
Light
full-sun, part-sun
Moisture
low
Spacing
18 inches
Classroom prompts
- Which plant traits are observations, and which are care recommendations?
- How would this plant fit change if the garden location moved warmer, colder, wetter, or drier?
- Which source-backed facts would you cite in a lesson handout?
Use the Sources & citations section below for page citation styles and the field-level source list.

Sources & citations

Cite this page
For lesson plans, articles, or research that uses this page. To cite a single upstream fact instead, use its specific source listed below.
Plotwright. (2026, May 17). Red valerian (Centranthus ruber). Retrieved 2026, June 30, from https://plotwright.com/plants/centranthus-ruber
Sources for every fact
Every fact on this page traces to a source. 18 fields cited - 18 source-backed.
RHS Find a Plant
Botanical research database
Backs 17 fields
Identity
Summary
Plant type
Light
Moisture
Hardiness
Heat zone
Size
Spacing
Habit
Design roles
Seasonal interest
Growth stages
Lifecycle
Regional guidance
Success tips
Designer notes
Wikimedia Commons
Photo · CC BY 4.0
Backs 1 field
Image
GBIF
Botanical research database
Wikipedia (ecoregion articles)
Botanical research database