Thompson & Morgan

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New Zealand Yam

Oxalis tuberosa, Oka, Oca

Tender Tuber

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  • Introduced exclusively by T&M
Also known as the New Zealand Yam, this unusual member of the Oxalis family has long been grown in the Andes for its nutritionally rich tubers with a tangy lemon flavour that becomes nuttier once cooked. The red skinned tubers have a crisp pale orange or creamy coloured flesh that can be eaten raw in salads or boiled, baked, and fried - just like potatoes. You can even add the attractive shamrock-like leaves and shoots to salads for a refreshing citrus twist. Oca makes a particularly attractive crop in the vegetable garden or even in a container on the patio. Height: 30cm (12"). Spread: 60cm (24").

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How to grow Oca (New Zealand Yam)

Ideal For:
patio, kitchen garden, greenhouse
Flowering Period:
August, September
full sun
    • 5 New Zealand Yam tubers

    • Despatch: By end of March 2016
    • £5.99
    • 10 New Zealand Yam tubers

    • SAVE £3.99  
    • Despatch: By end of March 2016
    • £11.98 £7.99
Pot up Oca tubers individually into 15cm (6") pots of good quality compost and grow them on in warm, frost free conditions. When all risk of frost has passed, plant Oca out in any well drained soil in full sun. For optimum tuber production grow Oca at a distance of 90cm (36") apart, and cover with fleece until fully established.

Water Oca regularly, particularly during dry periods and especially from mid September when tubers begin to develop. An occasional feed with a general fertiliser and a mulch of well rotted compost will also help to encourage strong growth.

Oca requires long day lengths to grow and will not initiate tuber production until day lengths shorten in the autumn. Some tubers may form on the stems and these should be harvested before the first frosts. Do not harvest the underground tubers until the foliage has become frosted and died back in late November and December. Carefully lift tubers taking care not to bruise them. Oca tubers can be stored for several months in a cool frost free shed. Do not exclude light as this will help to sweeten the tubers.

Seeds and garden supplies will normally be delivered within the time period stated against each product as detailed above. Plants, bulbs, corms, tubers, shrubs, trees, potatoes etc are delivered at the appropriate time for planting and will be stated on the product page or in your order acknowledgement page and email.

Orders for packets of seed incur a P&P charge of £1.95.
Orders which include any other products will incur a P&P charge of £4.95.
Where an order includes both packets of seeds and other products a maximum P&P charge of £6.90 will apply - regardless of the number of items ordered.

Please see our Delivery / P&P page for further details and details of any surcharges that may apply to certain destinations.

  1. great alternative to potatoes

    By Joelle Nicholson 10-08-2014

    I first came across these in NZ and loved them. They make a great alternative to potatoe wedges. I had to wait 10 years for them to appear in this country and was delighted to find them at T&M. I have had years of blight up in Scotland so wanted an alternative to potatoes and this year have replaced half of them with this crop in my allotment.


    Thank you for your review. I hope we can continue to be of service.

  2. Kiwi favourite but enjoyed by all

    By Jacqui Maxwell 16-03-2013

    For me it was like a taste of home when I proudly dug them up. Planted some in large pots and rest in a vegetable bed and the ones in the vege bed definitely did best. They were so easy to grow and it was great to have a plant I didn't have to protect from the frost. Had them roasted with Christmas dinner and pretty much continuously post that. Have kept some aside to plant this year and they have kept well. Highly recommended by a New Zealander (they are a staple veg at home) and also our British friends!

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