Old man’s beard
Look out for fluffy flower-seed clusters through winter
Location: nationwide Distinctive features:
grows up to 20m high, forming a dense layer of long, woody stems covered in thin, papery, heart-shaped leaves. Clusters of fragrant, creamy-white flowers smother the plant from December to May, followed by fluffy seed heads (which look like an old man’s beard) over winter. It is deciduous, compared to the similar-looking native clematis which is evergreen.
Why is it weedy: tolerant of cold, moderate shade, damp, wind, salt, and most soil types. It’s also extremely aggressive, climbing rapidly up and over the tallest canopy trees, smothering and often toppling them as they die out beneath. Lower growing plants also succumb to lack of light. It produces massive amounts of seed in colder areas, which is spread by wind and water, and remains long-lived if exposed to frost. Old man’s beard also grows readily from stem fragments, which are spread in dumped vegetation.
How to kill it
1. Introduce biological control agents wherever old man’s beard is common – contact your regional council for more information.
2. Slash thick stems (all year round) at 1m and ground level (to prevent stump resprouting and aerial roots attaching from hanging stems). Paint cut stumps with glyphosate (250ml/L) or metsulfuron-methyl 600g/ kg (5g/L) or a product containing 100g picloram+300g triclopyr/L (100ml/L) or triclopyr 600 EC (100ml/L) or triclopyr 120g/L (500ml/L) or Banvine (200ml/L) or dicamba 50g/L (400ml/L) or picloram gel. Leave stems in air to die. Dispose of cutaway segments at a refuse transfer station or by burning.
3. Spray (spring-autumn): glyphosate (20ml/L) or clopyralid (12.5ml/L).
How to stop it coming back
Stumps and cut stems can resprout very quickly. Replant bared areas promptly to minimise seedling regrowth. Check for seedlings at least 6-monthly.
MY BLOCK may have problems with tarweed and buttercup, but we don't have any thistles, and I'm grateful.
I don't like thistles and remove them as soon as I see them. I hate picking up a bale of hay and getting a thistle prickle in a finger.
The Scotch thistle is one the most common thistles in NZ, found on roadsides, in pasture, and waste areas throughout the country. Seeds usually germinate in bare soil in pasture or along roadsides in the autumn, but they can germinate at other times of the year too.
It's mostly biennial, germinating one year, surviving the first summer as a rosette, but only flowering during its second summer.
But some 'scotchies' can behave like an annual, germinating in autumn, bolting to flower in their first summer and spreading their seeds in the wind. The plant can grow in low or highly fertile soil and reach up to 1.5m high.
The main distinguishing features are the spines on the leaf surface, and around the leaf margin – most other thistles don't have prickles on the leaf surface.
Scotch thistles can colonise areas of pasture, reducing the available grazing. If dense stands grow in patchy pasture around water troughs, they can prevent stock from drinking as animals can be reluctant to push through the prickly plants. Sheep and cattle don't normally graze scotchies. Goats and some horses will eat the flower head.
How to control it
Dense, vigorous pasture stops scotchies colonising in the first place. If your pasture has bare patches due to insects, grazing damage, dry summers or wet winters, seeds can blow in and germinate in the soil.
Mowing in summer when the plants have bolted to flower head, but not seeded, gives good control. However, it's only effective at this stage, not at the rosette stage.
You can also use a sharp hoe to cut scotchies off at ground level, make sure to cut it off below the crown at the base of the leaves.
Sprays that won't affect your grass are available. Be aware that some sprays will damage clovers and other broadleaf plants. Always read the label and use herbicides responsibly.
NOTE: We recommend you get your own independent advice before you take any action on your block. Any action you take is strictly at your own risk.