The autumn flowering of Madeira Vine is a visual reminder of the local abundance of this weed in northern NSW and South-East Queensland. Madeira Vine is particularly common along stream banks where its tubers are actively dispersed and deposited by flood water to begin new infestations. It also occurs in many rainforest remnants, urban and rural backyards, gullies in Macadamia orchards and on roadsides. These infestations are usually the result of careless dumping of garden waste.

Madeira Vine is a particularly troublesome environmental weed to deal with. Despite the best efforts of bush regenerators it will always regrow. There are sites on the NSW north coast where Madeira has been actively controlled for around 20 years and it still manages to recur. Fortunately it does not set viable seed in this country. However rapid growth rates, combined with its ability to produce copious quantities of aerial tubers each growing season, make eradication an unrealistic goal. Control measures therefore aim to limit the spread of Madeira Vine while reducing the level of infestation.

Most Madeira Vine infestations consist of large vines growing up into canopy trees with clusters of aerial tubers attached as well as a dense ground layer of tuberlings and unsprouted tubers. There are also usually numerous tubers hanging up in canopy debris, growing within epiphytes as well as broken sections of vine growing and producing tubers even without contact with the ground.

The standard approach is to scrape long sections of the climbing vines with a knife, from ground level up to head height, and promptly paint with neat glyphosate. Scraping of Madeira must be done gently to avoid severing the vine, and for thicker vines should be deep enough to expose the white fibrous core of the vine. The vines are either carefully scraped and painted between the attached tubers or the tubers are removed from the lower section of the vine before scraping and placed in a bag. Bagging prevents aerial tubers from being knocked to the ground where they will eventually start growing. A proportion of the aerial tubers above the scraping will then rot with the rest of the vine and the remainder will fall to the ground. Where dense tuberlings occur around the climbing vines it may be beneficial to spray these before treating larger vines to avoid damaging them by trampling. Otherwise time must be allowed for them to recover to a sprayable condition. Standard spray application is glyphosate at the rate of 1:50 with water ( ie 200mL glyphosate per 10l water) plus LI 700 5mL/L of mix.

The key ingredient for the management of Madeira Vine at any site is regular follow-up weeding. It is easy to treat a large area of canopy vines initially, whereas it is very difficult to maintain a treated area over time. Areas of dense ground layer infestation typically require as many as 6 follow-up treatments per year to prevent the vines from climbing. It is essential that there is a consistent reduction of tuber input on a site for long-term success. Subsequent weeding of an area must occur regularly enough to prevent underground tubers from re-sprouting vines that climb up to produce new aerial tubers. Removal of available climbing ladders such as cut stems of Lantana is beneficial.

Madeira vines grow fastest (up to 1m/week) in high sunlight conditions coupled with good ground moisture (ie. most creek sides, rainforest understoreys). Given that primary treatment of canopy vines is usually accompanied by control of other weeds such as Lantana, Climbing Asparagus and Privet, sunlight levels in the treated area increase and so does the growth rate of Madeira. A decision to use either hand weeding or spray application of herbicide must be made on each site visit. The best choice will depend on the scale of infestation and the overall stage of the particular project. Spraying is usually the best option during the early stages of Madeira control when dense infestations are experienced while hand weeding is preferable when regrowth tubers are few and far between.

Good preparation of an area prior to spraying is important. The basic premise of bush regeneration is that a treated area becomes healthier and more diverse over time. In this way the bush thickens up, becomes shadier and slows the growth of Madeira. This means that excessive damage to native vegetation due to spray drift is unacceptable. Wind down vines growing into small trees and shrubs and place in a sprayable position. These must be left intact so that herbicide uptake through the foliage impacts underground tubers. Also, hand weeding should be undertaken around precious seedlings and invaluable groundcovers such as ferns and native herbs to ensure that these are not excessively damaged following spraying.

Tubers collected by hand should be placed in an onsite compost under black plastic or put in the bin. Hand weeding is very effective at removing large tubers that would otherwise require uncountable spray treatments over a long period of time.

Regrowth always occurs whether hand weeding or spraying is used due to the presence of un-sprouted tubers which are unaffected by either method. Deeply buried tubers are common in riparian environments and may be best treated by gouging and copious application with herbicide. Only experience and site familiarity can tell the practitioner what are replaceable losses when spraying. Spray-free zones must be maintained around rare and endangered plant species to ensure that these are not adversely impacted by well-meaning weed control.

The uptake of herbicide by Madeira tuberlings via spray application and subsequent damage to tubers is dependent on factors such as leaf surface area/tuber ratio, general health (weather conditions) and choice of herbicide. Spraying of tuberlings usually only results in partial decay of the tuber and in time regrowth of the same tuber. Small tubers may completely rot with only one spray whereas large tubers will require repeated spraying each time the tuber regrows. Some bush regenerators prefer to use Grazon or Starane as opposed to Glyphosate for additional impact on Madeira tubers. However these chemicals are not always suitable for use within high conservation value vegetation due to residual impacts. Brush Killer (Metsulfuron Methyl) may be added to Glyphosate spray mixes as a less toxic alternative. Note that herbicides used must be registered for use under permit for particular weeds. Consideration must be given to the fact that no matter the selection of herbicide, regrowth of Madeira Vine will always occur and therefore re-application of herbicide will be required. This means that chemical input to the same area will occur time and again.

There is no magic cure for the control of Madeira Vine. Effective treatment requires a long-term, well-planned strategy that utilises a range of techniques. The best approach involves consistency, patience and determination. As a rule of thumb – if you can’t commit to the follow up then don’t do the initial weeding.

Written by Darren Bailey