Arisaema costatum


Costatum has deep purple black spathes growing to 20 inches.

SKU: A6140 Categories: ,


Arisaema costatum is unusual looking but they are easy to grow and ideal for most areas in the UK. Arisaemas are unusual but superb and once established in a shady spot with good drainage and plenty of leaf mould, will require little attention.

They are quite spectacular plants for any garden. This variety has deep purple-black spathes tinged white, with large glossy leaves. Using bulb starter will help the arisaema to establish.

Cultivation instructions:

Indoor planting: Not suitable for growing indoors. Can be started off in pots inside and moved or planted outside once you see growth.

Planting outside: Ensure they are planted quite deep as doing this will protect the tubers and rhizomes from frost. Arisaema are happiest in soil conditions that are neutral to slightly acid. Cultivate soils to a depth of 20cms if possible and add plenty of grit and humus matter to the soil. Plant bulbs so that they are 10-15cms below the soil surface.

Can also look great if grown with martagon lilies, hostas or wood anemones.

Care tips:

Protect from severe frosts over winter by giving a good layer of mulch.

Remember to mark the position you plant them in as they can easily get lost.

Using bulb starter or root grow when first planting will help them to establish for future years flowering.

Hardy in UK gardens.

Growing Information:

Flowering Height: 16-20″ (60-90cm)

Flowering period: July-August

Soil type: Humus rich soils that are free draining. Neutral to slightly acid preferred.

Aspect: Semi shaded woodland areas.

Scented: No significant scent.

Planting Depth: 10cms

Spacing: 10-15cms apart.

Full growing instructions provided.

Additional information



Flowering time



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