Also known as: Common
coral tree
Family: Fabaceae Photo
© Big Scrub Rainforest Landcare Group
Many years ago, about 6 or 7 species of coral trees were promoted by the nursery
industry as a beautiful and easily grown ornamental tree. They were right on
both counts. Coral trees have bright red flowers from mid winter to mid spring,
and are very easy to grow - in fact, far too easy. They were known as instant
trees - in fact it was well known that you could break off a large branch and
just stick it in the ground and watch it grow! Two of the species became problem
weeds in this area.
The first is the Indian Coral or Cockspur Coral Tree (Erythrina crista-galli). Although not a major problem in the Wilsons Creek area yet, this may be a sleeper weed, and therefore it is strongly advised that all specimens be removed. This species spreads by seeds and vegetatively. Nurseries are still selling this species, but hopefully not locally.
The second is the Common Coral Tree (Erythrina x sykesii) seen predominantly along many of our creeks. It is a hybrid so thankfully does not produce seeds, but spreads readily vegetatively. It is semi-deciduous and very hardy - it likes the wet soils along creeks but also can adapt to dry areas. Logs, branches and even twigs readily regrow. The species also coppices and suckers. The wood is very weak, breaking easily, thereby spreading. It can block the flow of creeks and cause creek bank erosion, causing other trees to fall over. It has vicious thorns so needs to be handled carefully with gloves. Spikes require antiseptic to prevent infection.
Methods of eradication
The commonly used method of injecting the tree and leaving it to die only works
to some extent. Whilst the tree may look dead, the branches break and fall,
and later re-shoot either on your property or further downstream, creating a
worse problem than was originally there. If this method is the only alternative
available, vigilance is required over the next few years, in immediately collecting
and removing all fallen branches off-site and disposing of these.
Recommended methods include:
Organic: A backhoe is used to completely remove tree. This is a good method where there is easy access and where falling branches are a danger (near houses, play areas or roads), but is costly and causes substantial soil disturbance.
Physically Inject Chemical to Tree: The tree is injected with 100% glyphosate, and after at least 24 hours (it is preferable to wait till the tree de-foliates if possible, approx 6 weeks) it is then chopped down, with all pieces removed off site for disposal as above. If it is too difficult to remove the larger trunks and branches then you should inject these as well. The stump can be re-injected with glyphosate if it reshoots.
Inject Chemical to Stump: The stump is injected with 100% glyphosate then left standing. It can take from 6-18 months for the tree to fall over. Then remove all pieces from the site and as stated before, inject anything that is not completely removed. This can be done anytime of the year but is best in spring. The branches can be chipped, mulched or burned although burning is difficult due to the high moisture content.
Chemical injection requires a lot of poison and can be expensive, therefore
it is best to get trees when still young. The method of cutting trees and painting
the stumps is unlikely to work as the tree needs to be actively growing to circulate
the poison throughout the tree and roots. Any regrowth can be sprayed with glyphosate,
however, care must be taken, particularly if the site is close to a creek. Sprouting
logs can be regularly rolled and eventually they will die.
Injection methods
The methods of injection include:
Drilling: Use undiluted glyphosate. The holes can be refilled numerous times within a few minutes to ensure the maximum effectiveness.
Frilling: Use undiluted glyphosate.
Conclusion
Coral trees are very difficult to get rid of and are spreading more and more
into our area, requiring best practice methods plus lots of after-care. However
the benefits of their eradication and replacement with native rainforest species
is immense. Please note that the Landcare group supports organic methods of
weed control and eradication, but notes that organic methods have their limitations
and disadvantages, and that careful use of chemicals can often have a lesser
impact, and more positive effect on the environment. Please read all the safety
labels and information available about the chemical before using it, and seek
advice where necessary. Protective clothing, gloves and glasses should be worn.