Aristolochia clematitis

RHS Plant Profile

birthwort

RHS

Other common names

upright birthwort

Herbaceous Perennial

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A perennial, to 90cm tall, with creeping, branched rhizomes and heart-shaped mid to dark green leaves on upright, then scandent, stems. Narrow, tubular pale-yellow or yellowish-brown flowers, with pointed, curved upper lips, are produced from late spring to midsummer

Position

Full sun, Partial shade

Soil Types

Chalk, Loam, Sand

Max Height

0.5-1 metres

Max Spread

0.1-0.5 metres

Size

Time to Maturity: 2–5 years
Max Spread: 0.1-0.5 metres
Max Height: 0.5-1 metres

Growing Conditions

Chalk Loam Sand

Moisture: Well–drained
pH: Acid or Alkaline or Neutral

Position

Full sun Partial shade

Aspect: South–facing or West–facing or East–facing
Exposure: Sheltered
Hardiness

Hardiness Ratings

All ratings refer to the UK growing conditions unless otherwise stated. Minimum temperature ranges (in degrees C) are shown in brackets

H1A: under glass all year (>15C)
H1B: can be grown outside in the summer (10 - 15)
H1C: can be grown outside in the summer (5 - 10)
H2: tolerant of low temperatures, but not surviving being frozen (1 to 5)
H3: hardy in coastal and relatively mild parts of the UK (-5 to 1)
H4: hardy through most of the UK (-10 to -5)
H5: hardy in most places throughout the UK even in severe winters (-15 to -10)
H6: hardy in all of UK and northern Europe (-20 to -15)
H7: hardy in the severest European continental climates (< -20): H6

Colour & Scent

Season	Stem	Flower	Foliage	Fruit
Spring
Summer
Autumn
Winter

Botanical Details

Family: Aristolochiaceae
Native to GB/Ireland: No
Foliage: Evergreen
Habit: Suckering
Potentially harmful: TOXIC if eaten. Wear gloves and other protective equipment when handling Pets (dogs): TOXIC if eaten - see the HTA guide to potentially harmful plants for further information and useful contact numbers
Genus: Aristolochia can be shrubs or herbaceous perennials, many climbing, usually with heart-shaped or ovate leaves. Distinctive flowers have an S-shaped calyx tube and no petals, and are may be white, yellow, brown or maroon, often mottled
Name Status: Correct
Plant Range: Europe

How to Grow

Cultivation

Grow in fertile, well-drained soil in sun or part shade; overwinters best in dry soils

Propagation

Propagate by seed in spring or propagate by division in summer or by root cuttings in winter

Suggested planting locations and garden types

Cottage and informal garden
Coastal
Flower borders and beds

Pruning

Pruning group 12; prune after flowering

Pests

Generally pest-free

Diseases

May be susceptible to honey fungus in gardens where it is present but insufficient data to determine degree of susceptibility