Old man's beard

What is it?

Old man's beard, close up of flowers and leaves. Photo: Susan Timmins.
Old man's beard, close up of flowers and leaves

Clematis vitalba (Old man's beard) is a fast growing, deciduous climber. Seedlings have one to three leaflets and the mature plant has five leaves. The flower appears in summer and early autumn, is creamy white in colour and is perfumed. The characteristic feathery seed heads give this climber its name and appear from autumn to spring. The vines have six strong longitudinal ribs. Older stems have pale brown stringy bark with longitudinal furrows.

Do not confuse Old man's beard with native clematis, which is three leaved, flowers from spring to early summer, seeds in late summer and has a smooth vine.

Why is it a problem?

Clematis vitalba, Old Man's Beard, close up of leaves. Photo: A.Thorpe.
Clematis vitalba, Old Man's Beard

Old man's beard is a vigorous plant. Each stem can produce up to ten metres of new growth in a season, and stems trailing along the ground can root at each stem node to produce new plants. Each plant can produce more than 100,000 seeds in a year, mainly spread by wind and water.

The habitat of this climber includes roadsides, river banks, gardens, hedges, shelter belts, disturbed forest and forest edges.

Old man's beard is capable of smothering large areas of native forest remnants. It scrambles and climbs over other vegetation including tall podocarp trees, denying them the light they need for growth and even breaking branches with the sheer weight of the vines. This creeper prevents regeneration in forest gaps by blocking light to the ground and taking over where other species could establish.

By killing native woody plants, Old man's beard destroys food sources for native species, including birds, lizards and insects. The creeper affects the ecosystem by killing trees and increasing the amount of dead material in forests.

Methods of control

Biological Control:

A leaf fungus (Phoma clematidina) was released in the 1990s. A leaf miner (Phytomyza vitalbae) and a sawfly (Monophadnus spiolae) have also been released.

Manual Control:

Small seedlings can be pulled out by hand. Large stems have to be cut, the roots grubbed out and placed off the ground where they cannot take root again.

Chemical Control:

A variety of chemical controls are effective against Old man's beard, including Roundup, Escort and Versatil. Spray should be applied from November to March. Use the concentrations recommended by the manufacturers. Take care to spray only in still conditions to avoid wind drift to non-target plants and don't spray when rain is expected.

During spraying, non-target plants can be shielded with cardboard, plastic sheets or a large plastic container. The use of a marker dye helps to avoid double spraying and wastage, and a foaming agent can be added to the spray to help prevent spray drift. As with all spraying you should read the instructions on the manufacturer's label closely and always wear protective clothing.

The best method of control is to cut vines to ground level or to waist level in the winter or spring and to spray the regrowth in March. This method ensures that if the climber has covered a host plant, it will not be affected by the poison along with the Old man's beard. Leave the vines in the tree to dry out before removing, to prevent damage to the host tree.

For larger specimens, the cut stump method can be used. Cut the base of the plant close to the ground with a straight flat cut. The cut must be horizontal so the herbicide will stay on the cut area and be absorbed. Apply herbicide immediately, as the sap ceases to flow once the tissues are severed. There are several convenient ways the application can be made, with a paintbrush, eye dropper or a small squeeze bottle. For larger specimens it is only necessary to wipe the herbicide around the outer rim of the cut.

Make sure you leave the plants in the ground until the roots have died off. Do not re-apply herbicide too soon after the initial treatment. Wait until the plant actively begins growing again. Old man's beard will not be eradicated in one season. You will have to watch for regrowth and seedlings and repeat your control measures.

Contact

Contact any Department of Conservation office for further information on the identification and control of invasive weed species.

Regional councils also have pest control officers who will be able to advise you on control methods.


Related link

Old Man's Beard Must Go! on NZ on Screen


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