Arisaema serratum
Japanese cobra lily
Also known as Arisaema japonica
- Height × spread
- 1.5m × 1m
- Position
- Tolerates full sun, likes part shade, tolerates light shade
- Hardiness
- Mild winter to -5C (RHS H3)
- Flowers
- Spring
Availability
Please ask in store about availability
Many plants are seasonal. Call 01234 567890 to check current stock.
About this plant
This generally has two leaves, each of which is divided into a variable number of oval leaflets. The leaves are green and may have purple mottling. It produces a flowering spathe during May or June. This is green or purple with white longitudinal stripes and has a long pointed tip. After this there is a columnar spike massed with brilliant red berries. This is a forest dweller that reaches around 1.5m (5ft) height with 1m (3ft) spread.
- Flower colour
- Purple, White
- Foliage colour
- Green, Purple
- Fruit colour
- Red
- Variegated
- No
- Scent
- No
- Shape
- Oval
- Height
- 1.5m
- Spread
- 1m
- Season of interest
- Spring, Autumn
- Flowers in
- Spring
- Evergreen
- Deciduous
- Garden style
- Rock garden, Exotic garden, Conservatory
- Sun or shade
- Tolerates full sun, likes part shade, tolerates light shade
- Soil type
- Clay, Loam (normal)
- Soil pH
- All types
- Drainage
- Moisture retentive soil, Well drained soil
- Hardiness
- Mild winter to -5C (RHS H3)
- Borders & containers
- Borders and containers
- Hazards
- Yes, potentially harmful; Humans: Harmful if eaten; skin & eye irritant
AutumnNow
Autumn - late · Outdoors
Apply a protective mulch
Protect the crown of the plant in winter in areas that are prone to frost and cold. For short term protection a fleece can be used, otherwise fill mesh sacks with masses of straw and secure them over the plant's crown.
The 'traditional method' is to put wire or other netting over the plant, layer plenty of straw on top of this and then secure the whole with more netting.
Spring
Spring - late · Outdoors
Feed with slow release fertiliser
Apply a general purpose slow release fertiliser, spreading it around the root area of the plant as it is coming into growth. (Or apply a liquid feed at regular intervals throughout the growing season.)
This is a simple way to provide a nutrient boost as a single annual procedure.
Spring-Autumn · Outdoors
Water to keep the soil moist
For best results, this plant needs soil that is always moist. Water deeply and regularly as soon as soil appears dry. Even for established plants in the ground, a dry week can cause problems with some soils. Check plants in pots more often, especially in hot weather. Or install an automatic irrigation system which will do the hard work for you, even when you are away on holiday.
Without regular watering some plants never fully regain their beauty.
Summer
Summer · Planting
Remove offsets to create new plants
Offsets are small plants or shoots that develop around the parent plant. They should have developed a root system of their own before they are detached. They can be planted directly, or grown in pots if so small they could be 'lost' in the garden.
Offsets may be used to replace an aged parent plant, to extend or establish a colony, or can be given away or sold.
Planting & general
Outdoors
Water with rain water
This plant needs rain water or soft water (the minerals in alkaline or "hard" water are harmful). This is especially important for plants in pots.
Compost · Planting
Ericaceous compost
This plant requires acidic (ericaceous) soil. Where the soil is not acidic, or when planting in pots, use an ericaceous compost.
Found in
More Arisaema
Arisaema candidissimum
White cobra lily
Arisaema concinnum
Elegant cobra lily
Arisaema consanguineum subsp. kelung-insulare
Cobra lily
Arisaema exappendiculatum
Appendixless cobra lily
Arisaema nepenthoides
Yellow cobra plant, Nepenthes like cobra lily
Arisaema sikokianum
Shikoku cobra lily
Arisaema tortuosum
Tortuous cobra lily, Tall cobra lily
Arisaema amurense subsp. robustum
Robust cobra lily