Spanish Moss living in Oak and Old Mans Beard, Savannah Photo L Brodie
A study by STEP
STEP is a community-based environmental organisation covering suburbs in northern Sydney from Ku-ring-gai and Hornsby local government areas and surrounding suburbs with a membership of over 550. Its primary aim is to work for the conservation of bushland in northern Sydney. STEP Inc, PO Box 5136, Turramurra, NSW 2074. Website www.step.org.au
In recent years STEP has become increasingly concerned about the proliferation of Spanish Moss on local trees and its potential impact on the bushland. In December 2023 we asked members to send us details of any Spanish Moss they have seen growing on trees. We then undertook a preliminary survey from Cowan to Marrickville, in Sydney to determine what tree species it grew on. What we found horrified us.
Method
Location was recorded as suburb, street, and coordinates. Family, scientific name and common name of the support trees were recorded where possible, but some introduced trees and shrubs were not differentiated into species and cultivars. Many introduced gymnosperms were only identified to family. The number of support trees was recorded but data about abundance, festoon thickness, location on the support plant, attachment height, length of longest festoon and support part was collected in classes, except for the measurement of spectacularly long festoons. General notes were taken including information about nearest infested trees and those that remained free of Spanish Moss.
Many of the worst infestations were added to iNaturalist and hence the Atlas of Living Australia under the name, persepolis22.
Most notifications of infestations of Spanish Moss were between the Parramatta River/Sydney Harbour and Cowan, but we were also notified of infestations near Lake Macquarie and in the Dulwich Hill area. Other observations were fortuitous as we travelled in the area. Most observations were of street trees and gardens viewable from the street.
Spanish moss on recently dead turpentine STEP
Trees most affected by Spanish Moss
Turpentine (Syncarpia glomulifera) is the most severely affected of all the 76+ species of plants we recorded Spanish Moss growing in. Infestations can be so dense and widespread that whole trees are festooned. Spanish Moss flourishes over turpentine leaves and worryingly it appears it may be able to kill mature trees by preventing photosynthesis. Locally, turpentines are important trees in the critically endangered Sydney Turpentine-Ironbark Forest and Blue Gum High Forest as well as in sandstone gullies. Their loss would be disastrous. Worse still, turpentines are common trees in fertile forests from well north of the Queensland border to near Ulladulla about 250 km south of Sydney. Our evidence suggests that Spanish Moss could damage turpentines all the way along the coast and ranges. We are not sure why it flourishes so well on turpentines but we are prepared to speculate that leachates from the fungi on the leaves encourages its growth.
More bad news for our rainforests and wet sclerophyll forests is that lilly pilly (Acmena smithii), Cheese tree (Glochidion ferdinandi) and brush box (Lophostemon confertus), all major components of our east coast rainforest, can be severely affected while coachwood (Ceratopetalum apetalum) and blueberry ash (Elaeocarpus reticulatus) can certainly carry Spanish Moss. In addition to causing damaged or dead trees, threats to ecosystems include subtle effects such as altered water and nutrient cycles, changed predator/prey interactions, habitat alteration, moderation of the microclimate and transformed fire regimes. Changes such as these are some of the greatest conservation threats to biodiversity in Australia.
The good news is that eucalypts, bloodwoods and Sydney red gum (Angophora costata) seem to be resistant to it. We only repeatedly recorded Spanish Moss flourishing on red mahogany (Eucalyptus resinifera).
Spanish Moss weed wise Photographer Forest and Kim Starr flickr.com
How it spreads
Spanish Moss is obviously well loved by many gardeners, but STEP is not sure that gardeners realise how rapidly it can grow and spread. What today may be a gentle grey ornamental addition to the garden, may overwhelm it with dense heavy screens of moss up to 3 metres long over a few years. Overseas, festoons over 8 metres long have been recorded. The artistic addition to the garden today may be a nightmare tomorrow. You may think that your garden is safely distant from bushland, but we recorded a jump of 70 metres from the nearest Spanish Moss when it was used by noisy miners in their nest. All gardens must therefore be viewed as sources of bushland infestations.
Spanish Moss can spread in several ways. Asexual spread can occur with the tip of plants blowing in the wind and becoming entangled in other parts of the plant or a different plant. Birds are obvious dispersers as they move Spanish Moss for nest construction.
Physical control will be difficult as it is an air plant and has no contact with the ground. In most cases we found it out of reach, sometimes 15 metres up a tree. We haven’t trialled chemical control methods used in the USA, but they are listed in our report.
Control
One of the main barriers to control is the fact that many gardeners and horticulturists love it and actively spread it. Education about its damaging impacts is needed and it has recently been added to the NSW WeedWise website https://weeds.dpi.nsw.gov.au/Weeds/SpanishMoss as a Sydney issue and added to the Sydney Weeds Network website https://sydneyweeds.org.au/.
The ideal answer to control would be a specific biological control but its very low protein content makes it largely unpalatable.
Hand removal is often recommended as the best way to kill Spanish Moss, but in our survey only approximately 12% was in easy reach.
Chemical control methods in the Americas involve spraying festoons with various solutions. Experimentation would be needed to ascertain effects on Sydney conditions, particularly in bushland.
Recommendations
- Gardeners and regenerators remove all moss they can reach, put it in their green bin and prevent spread.
- Local authorities such as local councils and NPWS remove it from all public places, including trees on nature strips.
- Add Spanish Moss to the next iteration of the Greater Sydney Regional Strategic Weed Management Plan and all other relevant regional strategic weed management plans.
- Classify Spanish Moss at a level that enables its eradication and containment, prohibition of sale and distribution, e.g. as a regional priority weed.
- Undertake research into why turpentines are a favoured host and the ecological effects of Spanish Moss on bushland.
- Undertake research into control methods.
Summary Published in STEP Matters 228 Sunday, 08 December 2024 19:10
More information on Spanish Moss and its effect on native species is found in the report, which can be found on the STEP website – Spanish Moss (Tillandsia usneoides)– An Environmetnal Weed
STEP Inc 2024, Published by STEP Inc
ISBN: 978-0-9578390-7-6
Researched and written by Robin Buchanan
Edited by Helen Wortham
WHAT IS SPANISH MOSS
Spanish moss (Tillandsia usneoides) is also commonly known as old mans beard, and numerous other names occur around the world. Tillandsia species are commonly called air plants. It is neither a lichen nor a moss but is a member of the bromeliad family, Bromeliaceae, and it has the widest distribution of any bromeliad. It is not native to Spain!
It is an epiphytic flowering plant that often grows upon large trees in tropical and subtropical climates. It is native to much of the Americas being found in Central America, South America the Southern United States, and West Indies.
Spanish moss (Tillandsia usneoides) was introduced to Australia, probably through early garden development. It has become a naturalised weed in coastal areas of Queensland and New South Wales, where it grows on trees in moist subtropical climates.
Myths and stories about Spanish Moss
Long ago, in the Deep South of America, lived a man so cruel that even the land rejected him. His long white hair tangled in the branches of an ancient oak, trapping him forever. By morning, he was gone, leaving only ghostly strands swaying in the breeze—what people now call Spanish moss. To this day, folks say the ‘Meanest Man Who Ever Lived’ got his revenge.
Years later, Henry Ford saw the moss and used it to stuff Model T car seats. But he didn’t know it was home to biting chiggers. Soon, passengers found themselves scratching furiously, leading to history’s first automotive recall.
Stories obtained using CHATGPT.
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