DEPARTMENT OF PRIMARY INDUSTRIES

Moon cactus Harrisia martinii

Victorian Alert Weed Fact Sheet Plant biology Type of weed: Garden escape/agriculture. Lifeform: Spiny, succulent perennial shrub. Description: Stems: Moon cactus has fl eshy, multi-jointed stems with triangular humps sprouting spines and dark green in colour. Stems growing up to three metres long with lengthwise ribs, giving a plaited rope like appearance. Stems can develop roots wherever they contact the ground and broken stems can grow into new plants. Leaves: Like most cacti, true leaves are absent and modifi ed into the spines which helps the plant reduce moisture loss. Without true leaves, Moon cactus relies on its green stems to Images: Les Tanner & Sandy Lloyd Images: Les Tanner photosynthesise. Flowers: H. martinii belongs to a group of cacti Botanical name: Harrisia martinii. whose fl owers open at night, hence its’ most Synonyms: Eriocereus martinii, Cereus martinii. popular common name ‘moon cactus’. Flowers Common name: Moon cactus. are large, usually 150-200 mm in length, and Alternatives: Harrisia cactus, Martins apple-cactus, snake cactus. are short lived, withering in the morning. Moon Family: Cactaceae. cactus fl owers are white and showy, sometimes Relevant relatives: Harrisia martini is among many of the highly with a pink tinge around the outermost petals invasive cacti that plague agricultural and natural landscapes. It is and grow singly from a fl ower stem. closely related to Harrisia tortuosa (harrisia cactus), another spiny and invasive South American cactus – troublesome in northern NSW. Fruits: Moon cactus fruit are round, bright red in colour, 40-50 mm wide and have bumps and spikes similar to those found on the stems. Fruit contain a white fl eshy pulp, attractive to birds, mammals and ants. Seeds: Each fruit contains between 400 and 1000 small black seeds, held in the white pulp. The fruits split open when ripe, encouraging the seed and pulp to be eaten by animals, aiding spread. Moon cactus can produce seed at just six months of age and can fruit nearly all year round. Roots: Moon cactus has two root distinct root types that maximise its drought tolerance, shallow feeder roots that grow horizontally up to two metres and secondary tuberous roots which grow to depths of 150-600 mm, storing energy reserves. The underground tuberous roots have dormant buds, capable of re-shooting when the above-ground growth dies, even following herbicide treatment (PPDC 1980).

Weed Alert! Moon cactus Harrisia martinii

Victorian Alert Weeds Importance & impacts Impacts: Ecosystems, waterways and agriculture: What are Victorian Alert Weeds? Moon cactus is an aggressive competitor that can spread very quickly. When established, moon cactus Victorian Alert Weeds are potential weeds of the can quickly choke out competing plants, reduce future. They may pose a serious threat to Victoria’s species richness and establish a single species agricultural and natural assets or could affect stand. The impenetrable growth can restrict animal human health. Some of these weeds are thought movement and access to food, shelter and water. to occur in small numbers in Victoria and are still Mechanical treatment of infestations may pose eradicable. Other species are yet to reach Victoria, signifi cant ecosystem impacts including native but present a serious threat if they were to arrive. habitat destruction and erosion problems. Moon Weed Spotters help the Department of Primary cactus is a serious threat to the grazing industry Industries validate the distribution of these weeds. because the cactus can choke out pasture, reduce Weed Spotters are individuals trained to look for the land available for grazing and the plant’s sharp and report high priority Weed Alert species in spines make infested pastures hazardous for stock Victoria. They are recruited from the community, (Land Protection 2007). Tilling or soil disturbance government or industry. near infested areas may also spread the plant further across the landscape. Social value and health impacts: Collectors and plant enthusiasts may value cactus species such as Harrisia martini for their unusual form, fl owers and fruits. There is little known about the toxic properties of moon cactus. Cacti generally have little need for Why is this species a toxic chemical defences as they are equipped with Victorian Alert Weed? sharp spines to ward off hungry herbivores. Health hazards: The sharp spines of moon cactus Harrisia martinii has already proven to be an can cause serious injuries to both humans and invasive and destructive weed in northern parts animals if contact is made with the plant. Extreme of Australia. The numerous sharp spines on the care should be taken when handling, treating or plant may restrict the movement of livestock and removing the cactus. native animals, and the twisted spiny stems could provide harbour for unwanted pest animals. Moon Importance: cactus is very hard to eradicate because of the extensive energy stores within its tuberous roots, Weed legislative status: Harrisia martinii is a which enable the plant to regrow after mechanical declared noxious weed in New South Wales, Western or chemical treatments. Moon cactus has the Australia, Queensland and the Northern Territory. potential to spread into Victoria from the north Signifi cance of the weed in Australia: and the Weed Spotter network should remain H. martinii was fi rst planted in Collinsville vigilant in their surveillance for this species. Queensland as an ornamental in the late 1800s. The cactus was swapped with other plant enthusiasts when it outgrew its original pot, with subsequent overgrown pots being discarded into nearby scrub. Bird and animals feeding on fruits of the escaped plant helped it rapidly spread through the district (Mann 1967). Moon cactus has now become a major weed in Queensland and the Northern Territory, and is also becoming troublesome in New South Wales and the northern pastoral districts of Western Australia (Paskins 2001). Permitted/prohibited entry into Australia: Harrisia martinii plants and seed are not permitted entry into Australia. For more information see the AQIS ICON import conditions database at www.daffa. gov.au/aqis/import/icon-icd or call 1800 020 504. Victorian Weed Risk Assessment: Moon cactus ranked highly as a risk to Victoria due to its invasive potential and its persistence once established. Moon cactus is very hardy and can cope in environmental extremes such as fl oods, excessive heat and drought events. This cactus species is not easily eradicated because of its regenerative potential, including the ability to regrow from seed, stem tips, dormant buds and broken stems. Growth & spread

Reproduction and dispersal: The moon Seed bank/propagule persistence: The seed cactus can reproduce vegetatively from stems bank of moon cactus has a high germination rate tips that take root when they touch the ground or and remains viable in the soil for around fi ve to from broken stems. Unlike many other cacti that seven years (Mann 1967). The plant is extremely reproduce mostly from broken stem fragments, diffi cult to eradicate because of its persistent moon cactus also reproduces from seed (Moran & root system and the dormant root buds that can Zimmermann 1991). The main mode of dispersal regenerate after the plant has been removed or for moon cactus is from seed movement by birds, poisoned. animals and ants (Mann 1967). Floodwaters can carry plant propagules (seeds/stem fragments) in Origin: South America (Argentina and Paraguay). stream fl ow to form new infestations. Where it grows: Initial H. martinii infestations Rate of growth and spread: The rate of in Australia were limited to scrubland; however, spread of moon cactus, even from a single cactus infestations have since been discovered in plant, has been described as frighteningly rapid. more dense environments such as box ironbark Cactus species are usually quick to grow from forests and pine forests. Moon cactus is now stem fragments, but moon cactus is especially most commonly found in marginal grazing lands threatening as at can rely on seed production of Australia. The plant is very tolerant of shade as well. Moon cactus seedlings quickly develop and given the chance will form dense thickets a tuberous food storage root, which generates (Paskins 2001). Plants tend to reach their maximum further energy stores and penetrates deeper and development in shade and sheltered environments, deeper into the soil as the plant grows. but dense infestations can also persist when plants are left exposed after disturbance (Land Protection 2007).

Growth calendar Jan Feb Mar April May June July Aug Sept Oct Nov Dec

Flowering

Fruiting

Seeding

Germination

Notes: Growth calendar is broadly based on behaviour and timing of plant changes, either from overseas populations, or from limited populations in Australia. Actual behaviour of plants may differ, depending on climate and geographical location.

Weedy distribution in Australia and Introductory pathway to Australia: Moon overseas: In Australia, moon cactus is considered cactus was introduced into Australia as an a serious weed in Western Australia, Queensland, ornamental and has since spread from its initial New South Wales and the Northern Territory. infestation in northern Queensland to neighbouring Overseas, moon cactus is listed as a weed in South States and Territories. Its spread to agricultural Africa and Hawaii. areas was helped by birds and animals eating the seeds and it may have been intentionally spread by people sharing samples of the plant. Moon cactus may still enter the country accidentally via contaminated produce, clothing or equipment, or intentionally via the mail system or in luggage. For Victoria, the main pathways of introduction may be through plant exchanges, through gardeners and collectors, as well as the accidental spread from interstate infestations in contaminated fodder, grain, vehicles, clothing and equipment. Moon cactus Harrisia martinii

Choosing alternative species

When choosing an alternative plant, attempt to source local native (indigenous) species from a nursery/garden centre in your area. Advice can also be sought from Sustainable Gardening Australia - a not for profi t organisation, promoting responsible plant choices - call (03) 9850 8165 or visit their website at www.sgaonline.org.au.

Further information about moon cactus can be found on the DPI website at www.dpi.vic.gov.au or check the references listed below. If you suspect you have found Harrisia martinii, report it to your local Weed Alert Contact Offi cer on 136 186.

References: Acknowledgements: This fact sheet was Land Protection. (2007). ‘Harrisia Cactus, Moon prepared by Richard Plant and Stuart Roberton, Light Cactus; Eriocereus martinii and Eriocereus December 2007. tortuosus – Fact Sheet’. (Queensland Government, Department of Natural Resources and Water).

Mann, J. (1967). ‘The Harrisia Cactus’. (Queensland Department of Lands, Brisbane).

Moran, V. and Zimmermann, H. (1991). Biological Control of Cactus Weeds of Minor Importance in South Africa. Agriculture, Ecosystems and Environment 37, 37-55.

Paskins, M. (2001). ‘Agnote: Harrisia Cactus (Eriocereus martinii)’. (Weeds Branch, Northern Territory Government).

The Prickly-Pear Destruction Commissioner (PPDC). 1980. ‘The Prickly-Pear Pest in New South Wales’. Revised Edition. (The Minister for Lands, The Prickly-Pear Destruction Commissioner, Sydney). Printed on 100% recycled paper. Printed on 100% recycled

Published by the Victorian Government Department of Primary Industries Melbourne, March 2008. © The State of Victoria Department of Primary Industries 2008. This publication is copyright. No part may be reproduced by any process except in accordance with the provisions of the Copyright Act 1968. Authorised by the Victorian Government, 1 Treasury Place, Melbourne, Victoria, 3000 Australia. ISBN 978-1-74199-789-7 Disclaimer This publication may be of assistance to you but the State of Victoria and its employees do not guarantee that the publication is without fl aw of any kind or is wholly appropriate for your particular purposes and therefore disclaims all liability for any error, loss or other consequence which may arise from you relying on any information in this publication.

For further information, visit the DPI Website at www.dpi.vic.gov.au or contact the DPI Customer Service Centre on 136 186