Leafy spurge is one of the hardest weeds to kill or even control. It may be as high as three feet, and so thick you can hardly walk through it. It's a perennial. The leaves are bluish green, alternate, up to three inches long, narrow to slightly oblong. The flowers are greenish yellow, with up to 10 blossoms in a cluster at the end of branches. When a leaf or stem is broken, it bleeds a milky substance.

There are other plants that look like spurge but do not bleed milk. You can identify leafy spurge first by the blossom, then by the milk in the stem.

Leafy spurge usually starts from seed, but earth moved from an area where there is spurge could have some seed or some of the root system. It has a terrific root system, running deep and spreading like quack grass.

Once an area with spurge has been established, it's almost impossible to kill it right out because there are seeds in the ground that will sit there for years before they germinate.

I saw an excellent example. There was about a 10-foot circle of spurge plants that were spreading, but it had been there for several years. Other people had tried to kill it with different chemicals. I used Tordon* 22K and knocked it flat the first year, but the next year a few plants came up on the outer fringes of the patch.

So, I sprayed the original patch again plus about a four-foot perimeter all the way around the circle. The next year there were no plants. I was looking for little plants even an inch high and couldn't find any. This was the bottom of a road allowance ditch and there wasn't much growth there.

For three years there were no plants, so I thought I had beaten that patch -but not so. The fourth year I found several small plants. They almost had to come from seeds because I don't think the roots could survive three years with-out daylight.

So, to say you're going to spray it and kill it right out is not accurate. Spray with Tordon 22K, check it every year and spray every seedling you see and you can control it to the point that no one would know you have leafy spurge. If you don't check it every year, it will be right back up just as thick.

Tordon 22K is the best chemical we have now for spurge. It also has a residue that stays in the ground for two to three years, which gives more control. 2,4-D will burn the top growth off, but the next year it will be right up there just as thick, as it doesn't seem to hurt the roots at all.

A fellow once told me he had the answer to leafy spurge. He used atrazine, a sterilent. He had small patches; we checked one patch he had sprayed the year before and indeed he killed the patch because it killed everything, grass and all, just bare ground. Knowing spurge, I checked around the outside of the patch and found several plants. The roots ran outward from under the patch, then came up where there was no atrazine.

When spraying spurge, be sure to spray three to four feet all the way around the patch and take time to check it every year from then on. It takes only a few minutes to spray a couple of plants if and when they show up again.

There are beetles that eat spurge. We have several colonies of them working in Franklin Municipality. One type likes higher ground, while the other (a different-coloured beetle) prefers lower marshy ground. But, they are smart and think about tomorrow, so they leave some plants for next year. They will certainly help to control thick patches, but will not kill it out.

Sheep will eat spurge and control it, but if you don't pasture it each year, it will come back again.

In the U.S. a new chemical for spurge was advertised last fall, but only for control. If you don't do anything to leafy spurge, it will just continue to take over more area just like quack grass, and gets right out of control.

Leafy spurge spreads in many ways - by seed, cutting hay with spurge in it, then hauling it home and feeding it around the yard as well as dropping seeds along the road. Rotary mowers mowing road allowances spread leafy spurge from one area to another.

Spurge likes to grow in sandy or gravel ridges. So, if you crush gravel where there's spurge, the seed and roots will get spread all along the roads with the gravel. All equipment used to crush gravel will carry seed and roots on to the next gravel pit.

The seed gets washed down creeks and drainage ditches during high water. Birds also carry seeds.

For all these reasons, leafy spurge is one of the worst weeds we have.

Table 1 shows a list of our 10 worst weeds.




Source:
Cliff Grier farmed near Woodmore, Man., worked with the provincial weed supervisor for 10 years and recently retired.