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Ornamental tuber
Araceae
Summer bulbs and tubers
Van Noort
Griffith’s Cobra Lily (Arisaema griffithii)
Griffith’s cobra lily (Arisaema griffithii) creates an extraordinary woodland outline with a hooded green-to-purple spathe heavily veined in brown and large leaves divided into three diamond-shaped leaflets. The Van Noort package contains 2 tubers. Plants reach about 60 cm (24 in) tall and generally flower during May and June under bright partial shade. Grow in humus-rich, fresh, drained soil, ideally in a deep pot. The supplier’s Zone 4 claim conflicts with the RHS H2 rating; in Quebec, overwinter tubers reliably frost free. Wear gloves because every part is harmful if eaten and irritating. Its deep-container culture also makes drainage, seasonal movement, and monthly dormant-tuber inspection easier to manage safely.
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Discover the plant
Common nameGriffith’s cobra lily
FamilyAraceae
GenusArisaema
Speciesgriffithii
CultivarGriffithii
TypeOrnamental tuber
Botanical nameArisaema griffithii
Griffith’s cobra lily (Arisaema griffithii) is a striking tuberous perennial whose hooded spathe resembles an upright cobra head. Green to purple, heavily veined with brown, and 10 to 25 cm (4 to 10 in) long, this structure encloses a spadix carrying the minute true flowers. Two large leaves, each divided into three diamond-shaped leaflets, create an upright outline reaching about 60 cm (24 in) tall and 25 to 30 cm (10 to 12 in) wide. The Van Noort package contains 2 tubers. Its display generally appears during May and June before complete autumn dormancy.
Plant the 2 tubers in spring in humus-rich, acid-to-neutral soil that remains fresh but freely drained, under bright sheltered partial shade. Van Noort recommends 10 to 12 cm (4 to 5 in) depth, while RHS advises 20 cm (8 in); in containers, provide at least 15 cm (6 in) of cover without saturating the mix. Maintain regular moisture during growth, then reduce water as foliage yellows. The commercial Zone 4 claim conflicts with the RHS H2 rating. In Quebec, never expose tubers to deep freezing; grow them in a deep pot and overwinter reliably frost free.
Arisaema griffithii deserves a place beside a shaded path, in a sheltered courtyard, or at the centre of a large woodland container. Pair its graphic spathe with ferns, hostas, epimediums, and hardy begonias whose leaves emphasize complex veining without stealing light. Protect emerging shoots from slugs and monitor container plants for vine weevils. Every part is harmful if eaten and may irritate skin or eyes; wear gloves and keep the plant away from children and pets. Any berries remain ornamental only. Controlled winter storage must take priority over an unsupported hardiness claim, especially in Quebec’s deeply frozen soils.
In the garden
- Exposure
- Partial shade
- Life cycle
- Deciduous tuberous perennial requiring protected wintering
Planting guide
Sowing & germination
Planting depth
10 to 12 cm (4 to 5 in) per Van Noort; deeper cover in protected containers
Spacing / density
25 to 30 cm (10 to 12 in)
Best planting time
Spring, after the growing mix warms
Propagation
Remove offsets in late summer; sow seed in containers during spring or autumn
Growing method
In spring, inspect the 2 tubers and discard soft tissue. Fill a deep pot with humus-rich, airy, drained mix and set tubers with buds upward. Follow Van Noort’s 10 to 12 cm (4 to 5 in) depth while keeping cover stable and uncompacted. Maintain the mix at 18 to 22°C (64 to 72°F), lightly moist until emergence. Once shoots appear, gradually increase water and provide bright partial shade. Move the pot outside after frost risk into a cool, sheltered, ventilated place. Maintain regular moisture without saturation throughout growth. Protect shoots from slugs and inspect roots for vine-weevil larvae. Feed only after leaves open. In autumn, stop fertilizer, reduce water as foliage yellows, then overwinter the pot or tubers dry and frost free. Drainage must remain rapid even after heavy rain. A durable label prevents disturbance while tubers are dormant. Wear gloves and clean tools after every handling session. Always reduce water when leaves begin to yellow. Filtered light protects large leaflets from scorching. A deep pot makes Quebec winter storage much more reliable. Keep the plant away from children and pets because it is toxic. Watch for slugs as soon as young shoots break the soil.
Soil and care
Soil & care
Soil pH
Acid to neutral
Minimum temperature
Overwinter frost free; RHS rating H2
Care level
Advanced
Watering
Keep the mix lightly moist until emergence, then regularly fresh as leaves open and flowering develops. Water at soil level when the surface begins drying and let all excess drain away. Do not keep the crown constantly wet. As foliage yellows, reduce applications gradually, then store the tuber nearly dry throughout dormancy and frost-free wintering. Drainage must remain rapid even after heavy rain.
Soil type
Humus-rich soil containing composted leaves, acid to neutral, fresh during growth yet freely drained is ideal. A blend of woodland mix, fine bark, mature compost, and perlite suits containers. Avoid compact clay, filled saucers, and saturated peat pockets. During dormancy, conditions must become much drier to limit tuber rot. Drainage must remain rapid even after heavy rain. A durable label prevents disturbance while tubers are dormant.
Fertilization
After leaves unfold, apply balanced fertilizer at half strength every three weeks to moist soil. Moderate feeding supports the spathe without producing excessively soft foliage. Flush the pot occasionally with clear water. Stop all feeding when autumn yellowing begins because a dormant tuber cannot use fertilizer and should remain nearly dry. Drainage must remain rapid even after heavy rain. A durable label prevents disturbance while tubers are dormant.
Moisture
Moderate ambient humidity is suitable where air circulates and the mix drains rapidly. Avoid cold, enclosed, saturated corners that encourage soft tissue. In a cold greenhouse or veranda, space pots, remove dead leaves, and water in the morning. During dormancy, favour a dry ventilated atmosphere rather than high humidity. Drainage must remain rapid even after heavy rain. A durable label prevents disturbance while tubers are dormant.
Seasonal care
In spring, repot tubers in fresh mix and start them at 18 to 22°C (64 to 72°F). Water sparingly before emergence, then increase gradually. Give young shoots filtered light and install a physical slug barrier. In early summer, acclimatize the pot outdoors after frost risk, in partial shade and sheltered from wind. Maintain regular moisture, feed every three weeks, and check for vine weevils. During summer, remove only damaged tissue with clean tools and never cut healthy leaves. In autumn, stop feeding as growth slows and reduce water when foliage yellows. After complete drying, cut it at the base. Before cold weather, move the container inside or lift tubers. Keep them dry, dark, ventilated, and frost free. During winter, inspect monthly, remove soft tissue immediately, and do not resume watering until new growth begins. Drainage must remain rapid even after heavy rain. A durable label prevents disturbance while tubers are dormant. Wear gloves and clean tools after every handling session. Always reduce water when leaves begin to yellow. Filtered light protects large leaflets from scorching. A deep pot makes Quebec winter storage much more reliable. Keep the plant away from children and pets because it is toxic. Watch for slugs as soon as young shoots break the soil. Gentle air circulation prevents stagnant moisture around the crown. Do not rely on the unsupported commercial Zone 4 claim.
Container growing
Container growing
Recommended pot size
35 to 40 cm (14 to 16 in) wide and at least 40 cm (16 in) deep
Choose a stable container 35 to 40 cm (14 to 16 in) wide and at least 40 cm (16 in) deep with large holes. Add drained mix, then set the 2 tubers 10 to 12 cm (4 to 5 in) deep with buds upward and enough separation. Use rich yet airy woodland substrate. Keep the pot at 18 to 22°C (64 to 72°F) until emergence, then provide bright partial shade. Water regularly without leaving standing water inside a decorative cover. After acclimatization, move it outside into shelter from wind. Rotate for balanced leaves and watch for slugs and vine weevils. In autumn, bring it inside before frost, reduce water as leaves yellow, and keep the mix nearly dry through dormancy. Repot only in spring while wearing gloves. Drainage must remain rapid even after heavy rain. A durable label prevents disturbance while tubers are dormant. Wear gloves and clean tools after every handling session. Always reduce water when leaves begin to yellow. Filtered light protects large leaflets from scorching. A deep pot makes Quebec winter storage much more reliable. Keep the plant away from children and pets because it is toxic.
Bloom and dimensions
Size, flowering & harvest
Mature height
About 60 cm (24 in)
Width / spread
25 to 30 cm (10 to 12 in)
Flower color
Green-to-purple spathe, heavily veined with brown
Foliage color
Green
Foliage type
Deciduous, two compound three-part leaves
Growth rate
Moderate
Growth habit
Upright, architectural, and clumping
Fragrance
Light fragrance
Bloom period
During May and June, a spathe 10 to 25 cm (4 to 10 in) long unfolds near the ground, green or purple and heavily veined with brown. Its hood encloses a spadix carrying minute flowers. Display depends on warm growth, filtered light, and regular moisture. A spathe may last several weeks when sheltered from wind and scorching sun. Drainage must remain rapid even after heavy rain.
Fruiting
After successful pollination, the inflorescence may form a spike of red berries. Fruiting is not guaranteed and depends partly on the plant’s functional sex and the presence of a compatible partner. Berries are strictly ornamental, harmful if eaten, and irritating. Never harvest them for consumption and remove them where children or pets can reach the container. Drainage must remain rapid even after heavy rain.
Garden associations
Companion plants & uses
Companion plants
Ferns, compact hostas, epimediums, small astilbes, and hardy begonias emphasize the spathe without dominating it. Choose companions enjoying bright partial shade, humus-rich soil, and regular moisture. In containers, keep their roots separate to preserve tuber space. Avoid xeric plants, aggressive ground covers, and any species requiring incompatible winter storage. Drainage must remain rapid even after heavy rain. A durable label prevents disturbance while tubers are dormant. Wear gloves and clean tools after every handling session. Always reduce water when leaves begin to yellow.
Plants to avoid
Avoid cacti, succulents, and xeric plants whose dry regime conflicts with active arisaema growth, along with vigorous ground covers that steal light and space. Do not share the pot with a plant requiring wet or very warm winter storage. These incompatibilities are cultural rather than chemical.
Garden use
Use Arisaema griffithii as a collector plant in a large deep container beside a shaded path or in a sheltered courtyard. Its hooded spathe rewards close inspection, while large leaves add volume to a woodland scene. In Quebec, mobile culture remains prudent: move the pot outside after frost and bring it inside before cold. Every part is ornamental and must never be eaten. Drainage must remain rapid even after heavy rain. A durable label prevents disturbance while tubers are dormant.
Frequently asked questions
Frequently asked questions
Why must Arisaema griffithii be overwintered frost free?
Van Noort’s Zone 4 and −34°C claim is not supported by the RHS profile, which rates the species H2 and requires winter protection. This discrepancy is too large to risk the 2 tubers in Quebec ground. Grow them in a deep pot, move it outside after frost, and bring it inside before autumn cold. As leaves yellow, reduce water, then keep the tuber nearly dry in a dark, ventilated, frost-free place. This method follows the more cautious horticultural source. Never infer an exact minimum temperature from a conflicting commercial zone statement. Drainage must remain rapid even after heavy rain. A durable label prevents disturbance while tubers are dormant.
How deep should the tubers be planted?
Van Noort indicates 10 to 12 cm (4 to 5 in), while RHS recommends 20 cm (8 in). For mobile Quebec culture, use a pot at least 40 cm (16 in) deep and set tubers 10 to 12 cm down in stable, airy, drained mix. Slightly deeper cover may be used in a large protected pot, but it must never create a cold waterlogged pocket. Face buds upward, water lightly until emergence, and label the position. Drainage and controlled winter storage matter more than excessive depth. Drainage must remain rapid even after heavy rain. A durable label prevents disturbance while tubers are dormant.
How can tuber rot be prevented?
Begin with a firm tuber and a perfectly clean pot with large drainage holes. Use humus-rich yet porous mix containing fine bark and perlite. Before emergence, keep it only lightly moist; increase water as leaves develop. Always empty decorative covers and avoid continually wetting the crown. In autumn, reduce applications quickly as foliage yellows. During dormancy, store the tuber nearly dry, ventilated, and frost free. Inspect monthly and promptly remove soft tissue with a disinfected tool. Never repot an injured tuber into wet mix. Drainage must remain rapid even after heavy rain. A durable label prevents disturbance while tubers are dormant.
Why is this plant considered toxic?
Arisaema griffithii belongs to the Araceae and contains irritating substances, including calcium oxalate crystals. RHS states that it is harmful if eaten and irritating to skin and eyes. Never consume tuber, leaf, spathe, or berry. Wear gloves during planting, avoid touching your face, and wash hands and tools after work. Keep the container away from children and pets. If berries develop, remove them in accessible places. After suspected exposure or ingestion, promptly contact a healthcare professional or veterinarian. Drainage must remain rapid even after heavy rain. A durable label prevents disturbance while tubers are dormant. Wear gloves and clean tools after every handling session.
Why does the spathe resemble a cobra?
The spectacular “flower” is mainly a spathe, a modified bract enclosing the spadix that carries minute true flowers. In Arisaema griffithii, it expands into a hood, becomes green or purple, and develops strong brown veins. This combination creates the impression of an upright cobra head. The 10 to 25 cm (4 to 10 in) structure is best observed under filtered light beside a path. Do not handle it with bare hands because the plant is irritating. Protect it from wind, scorching sun, and slugs to preserve its pattern. Drainage must remain rapid even after heavy rain. A durable label prevents disturbance while tubers are dormant.
Wildlife and pets
Wildlife & precautions
Reported toxicity
Yes
Supporting wildlife
Minute flowers on the spadix may attract small insects associated with Arisaema pollination, but this contribution is specialized and variable. Never present berries as wildlife food because they are toxic. Avoid insecticides on the spathe, keep the plant beyond animal reach, and remove fruits wherever they create a risk. Drainage must remain rapid even after heavy rain.
Outils
Compostage et écologie
