Grown primarily for its dramatic, hooded flowers, Arisaema, commonly known and Cobra Lily, brings strong architectural interest to shaded parts of the garden in spring. It favours moist, humus-rich soil and a position in full or partial shade, making it well suited to woodland gardens and low-lying areas. Its bold foliage and distinctive blooms create a striking focal point in tricky shaded corners, making it a great choice for urban gardens where surrounding buildings cast shade. These exotic-looking plants are not hardy and require protection from freezing conditions, apart from Arisaema tortuosum which is slightly more resilient and can tolerate temperatures down to -5C.

How to plant:

— Arisaema tubers are supplied in spring for planting between February and May. Unpack the tubers on arrival and plant as soon as possible while they are fresh for best results. Do not store tubers for prolonged periods as they will lose their freshness and viability.

— It is not recommended to plant Arisaema tubers directly into borders, they should be potted up and grown on for a few months then transferred into borders once some growth as established.

— Pot up into individual 15-20cm diameter pots with multipurpose compost. Plant shallow, ensuring the tuber is fully submerged in the compost and the bud is level with or only very slightly below the soil surface.

— Water thoroughly after planting and ensure the soil is kept moist while growing on in pots an throughout the growing season.

— Arisaema can also be grown permanently in patio containers. If you intend to grow your Arisaema in a patio container, there is no need to pot up and grow on first. You can plant directly into a 20-30cm+ diameter patio container filled with good quality multipurpose compost.

— If your Arisaema is intended for a border, you can transfer it from the temporary pot it was started in into the border once risk of frost has past (after around early May), and once the tubers have established some growth. The plant will ready to transfer into a border once it easily comes out of the pot with the soil held intact by the roots. This typically takes a few months from planting, depending on the size of the pot and when it was planted. Allow the compost in the pot to dry slightly before removing the pot, this will help the soil stay attached to the roots during transfer.

— Choose a position in full or partial shade with rich, moist soil. Space the plants 20-30cm apart if planting in groups. Add multipurpose compost to each planting hole when planting, this will add nutrients as well as providing a soft medium to help the new roots grow. Water thoroughly after planting.

— Mark with a cane and monitor closely during the first growing season, ensuring the soil is kept moist and that more established plants or weeds are not encroaching/smothering.

— Arisaema are not hardy and can't tolerate freezing conditions, apart from Arisaema tortuosum which can tolerate temperatures down to around -5C. When potting up during spring while there is still a risk of frost, start in a cool, bright place indoors or in an unheated greenhouse.

Aftercare

— Arisaema benefits from consistently moist soil, particularly during active growth in spring and early summer. Water well in dry spells, especially if the soil is light.

— Foliage should be left intact after flowering, as this helps feed the tubers for the following year. As the plant dies back naturally in late summer or autumn, old stems can be removed.

— Re-pot container grown plants annually, or top dress with a generous mulch of compost to feed the plant.

— These perennials establish over time and may not always flower in the first year. They should always produce foliage in the first year, usually by June when planted in spring.

— In areas where frost or freezing temperatures are likely over winter, lift Arisaema tubers out of the ground, allow to dry and then store in cool, dry and frost free conditions for winter. If grown in containers, they can be moved under cover for winter. Arisaema tortuosum is hardier than other species and can survive temperatures down to around -5C, this species will however benefit from a topping of mulch over winter.