Thursday, May 19, 2022

A Californian thistle in my side

Steve Wyn-Harris has been struggling to keep Californian thistle in-check on his farm and hopes to have finally found the remedy. Photo: Wikimedia Commons

“NATIONAL frontiers have been more of a bane than a boon for mankind,” wrote D.C Thomson, a Scottish newspaper publisher in the 19th century.

It became prophetic with two world wars closely following and yet another example as we watch the pointless destruction and suffering of Ukraine by Russia.

However, it’s the word bane that brought me to this aphorism rather than a desire to delve into world affairs.

A bane is a source of harm or ruin, or even a curse.

The bane of my life in recent years have been Californian thistles.

The Californians call them Canadian thistles and even this is not fair as they came to the Americas from Europe with seeds in the 17th century.

That’s likely how they ended up here as well.

There have always been Californians about but for some reason in the last few years, they have become worse rapidly and now instead of an unsightly inconvenience are beginning to become production-limiting in the areas they are invading.

I wonder if my improved soil fertility levels and the recent droughts reducing any other plant competition have encouraged them.

The worst paddocks for the last two or three decades happened to be a couple of roadside paddocks on peaty soils next to a creek, so I assume they have their extensive root system down into the water table.

Most of us are probably guilty of a spot of window farming and I’ve been no different with these paddocks.

Most years I’d take the old tractor around to these paddocks and give them a good topping, but they would make a comeback later in the season. To be truly effective, one needs to continue to top them each time they make a revival to deplete their root reserves. But I’ve lacked the perseverance.

Then I bought a modest weed wiper and would drag this over them, but with mixed results.

The glyphosate would check but not eradicate them and I’d be back at it each year. Mind you, the wiper with glyphosate was effective against rushes so all was not lost.

I did experiment with hormones through the wiper, but again with variable results and the next year the thistles would come back stronger than ever.

A recommended practice was to hard graze with stock, but I’ve never been keen to thrash my ewes to get them to help me with my thistle problem.

There was an attempt to introduce a beetle for biological control, but it hasn’t been successful, and I do see the rust fungus on the thistles, but it has made little difference to their vigour.

I have double-sprayed glyphosate on bad Californian paddocks with a summer fallow before drilling crops, but that first spray encourages the thistles as they have no other competition. One time I did a third spray and that was effective on those particular paddocks but can’t be a sustainable option, although I’m desperate enough to try anything.

Because I’ve spent my whole pastoral farming career doing everything I can to grow clover, I’ve always been a reluctant broadacre sprayer of hormone herbicides, but have resorted on occasion to get the spraying contractor to spray bad patches of Californians. This because if there was clover among it, no stock was going to battle their way in to eat it and it was probably only supplying nitrogen to the thistles rather than ryegrass as intended.

I had hoped to exterminate the weed from at least these road paddocks before I died or retired but if anything, the thistles were more vigorous than ever.

Finally in desperation, I appealed to my seed supplier and expert James. I said I’d do anything to rid me of these accursed weeds.

He told me in that case, instead of my career’s half-hearted attempts, I needed to knuckle down and commit to the four-spray programme. I signed up on the spot.

The following early December when the thistles got to 10% flowering, the spraying contractor turned up and gave them a dose of herbicide with the usual satisfying unhappy thistle patches. But I knew they’d be back.

This time last year before the cooler weather, the regrowth got another spray.

Last spring, they struggled back to life but didn’t get to 10% flowering until later in January when we sprayed them once more.

Since then, the feed from two large rain events has completely swamped any regrowth to the point they are hard to find so I’m not going to spray them again this season, but will be prepared to do so again if they manage to make a comeback next season.

If it works on these areas, I’ll roll out the programme elsewhere targeting the worst and most annoying areas.

Hopefully, James’ recommendation, the spraying contractor and I become the Californians bane rather than the other way around.

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