Frequently Asked Questions
You keep talking about OMB. What is OMB?
OMB is short for Old Man’s Beard (botanical name Clematis vitalba), an introduced vine and a key threat to native species. It prevents the growth of seedlings and development of established plants, spreads quickly, and can strangle the lowest shrubs to the highest canopies. It grows in most soil types and flourishes in almost any climate. It is an extremely hardy and particularly difficult plant to eliminate.
Its copious seeds are carried by the wind so it can disperse over large areas fast - especially in Windy Wellington! In fact it was the second most observed species in the City Nature Challenge in Wellington in 2021.
If any roots are left behind, they may continue to grow. It's bad news.
Isn't Old Man's Beard an ancient rongoā / medicine?
You're thinking of Old Man's Beard Lichen (Usnea), also known as Beard Moss, which has a wide range of medicinal uses.
The plant we're tackling is a different Old Man's Beard (Clematis vitalba) which is an introduced pest plant in Aotearoa / NZ.
I don't like using weedkiller. Can I clear OMB without weedkiller?
You can, but you'll need to be extra vigilant to dig up and remove all roots. Anything not dug up - including root tips broken off - will regrow. Regrowth isn't the end of the world though - make a note to check the site a few months later. See Clearing Old Man's Beard for more info.
The roots of my OMB are inaccessible. Can I just spray it with weedkiller?
We don't have any experience with sprays, but have received the following advice:
Apparently Glyphosate will work OK but will kill everything else as well.
Metsulfuron is sometimes preferred since it is very effective on OMB and some natives (incl mahoe, kawakawa, hangehange and muehlenbeckia) are immune to it. But it is not suitable for use over damp soils and it does kill a lot of other plants too.
It really depends on what sensitive plants are present and to what extent you can confine the spraying to just OMB. Using low pressure with an air-induction nozzle will help.
I'd rather not leave the old man's beard to die off in a tree. Can I take it to the tip?
The Southern Landfill is the best place for it. It can go straight into the green waste to be commercially recycled into compost.
Depending on what you want to leave on their property it is only the stems, seeds & root balls that need to be removed. Composting it commercially the heat generated in the process kills all the weed seeds.
As of writing, the minimum charge is $5 (up to 60kg). Then if you have more, it is calculated by weight, and is $69/tonne. See landfill charges for current pricing.
You're dreaming! OMB is everywhere. Do you really think we can clear OMB in Wellington?
Are there biological controls for OMB?
Yes, Landcare Research have released a few biological controls. The aim is to introduce a balance where OMB is no longer considered a weed, but is not eradicated.
The leaf-mining fly is widespread, but is parasitised and not causing enough damage to OMB.
The Old Man’s Beard Eriophyid Mite (Aceria vitalbae) was released to 14 locations around NZ in August 2021. This causes leaf curl and reduces the growth of OMB. Spreading on the wind, it has reached over 65km from its release site in under 1 year!
For more details, see this Manaaki Whenua presentation.
GWRC tried to clear OMB 20+ years ago and gave up. What's different this time?
Well, 20 years ago we were lucky to see the occasional tūī. Now there are tūī everywhere, as well as kākā and kererū. Birds such as the tiekē (saddleback), hihi (stitchbird) and toutouwai (robin) are spreading out from Zealandia and we've even got the prospect of bringing kiwi back to Wellington! These birds will find it hard to survive if OMB is allowed to take control.
Coupled with the rapid rise of community groups trapping, weeding and planting out our town belt and reserves as well as residents planting natives in their road reserves, we think it might just be achievable.
Rather than relying on our councils to clear it all, we believe that our communities can clear the bulk of it, with support from the council to clear areas that need professional control.
These stems are going all over the place. How do I know where the roots are?
Check the nodes for two small white axillary buds. These will "point" towards the tip of the plant, so the roots will be in the opposite direction.
How do old men with beards feel about this?
Please don't call it Old Mans Beard. I’m an old man. I have a beard. Can't I call it something else?
Why not, the Dictionary of English Plant-names (1886) shows lots of alternate quaint names for Clematis Vitalba !