The Bindweed Horror

My house had been abandoned for 10 years when I bought it. Thus the yard was simply a jungle of monstrous vegetation. After several weeks of cutting and pulling the overgrowth, I thought I had it under control. I wanted a sustainable, natural yard, not a manicured lawn, so I largely allowed it to do what it wanted after that, just the occasional trimming. I was pleasantly surprised when a a vine produced pretty white flowers in the morning, which I (incorrectly) believed was morning glory. For years I allowed it to flourish, tearing it up when it started to take over. This year I realized the plant was not morning glory--it is bindweed. A quick Google could have solved this early on--bindweed produces a white flower, morning glory is other colors. I committed myself to its eradication.

Several websites offer suggestions for the removal of bindweed. The most extreme suggestion was simply to move away. The vigorous growth and nefarious root system makes it near impossible to eradicate. The University of California Extension says, "bindweed is one of the most persistent and difficult-to-control weeds in landscapes and agricultural crops." They suggest cultivating (i.e., pulling) it every 2-3 weeks to prevent germination. Other sites similarly recommend frequent pulling, claiming this will eventually "exhaust the roots." I don't know if this is accurate, but it sounds good to me, so that's what I have been doing for the last month.

The bindweed is mostly confined to the backyard, and specifically, only the north half, which is far sunnier, and separated from the south by a sidewalk. I have spent about 20 minutes in the morning, and another at night, scouring the yard for the telltale diamond-shaped leaves and/or viny appearance. Almost every site I found simply said to pull the weed, with no indication of trying to dig it out. However, after 2 weeks of picking about 75 bindweed plants per day, I dug one up and discovered the size of the root/rhizome--it's huge, as shown above. The UC site claims a plant can spread 10 feet from its root system. I switched my simple pulling to digging out as much as I can of each plant. Once you know what to look for, they are very easy to spot in a hunk of upturned dirt--they are thick, white, and make weird 90-180 degree turns, which can make them difficult to simply pull out of the soil without breaking off.

So far I haven't seen a significant decline in the number of bindweed found per day, but I can only assume it will eventually start working. The graph below (May 12-June 5; update on June 26 is below) shows the number of bindweed that I picked/dug up per day. The decline in the last few days could be a number of different factors--perhaps my hard work is paying off, perhaps I didn't spot as many as I should have, or the cooler nights might be inhibiting their growth (the last several nights have been in the high 50s, compared to nights in the upper 60s & low 70s for the previous few weeks).

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Update: June 27, 2018 (3 weeks later)

For the first 2 weeks of this project, from May 12-May 24, I was only picking the bindweed from the ground up, i.e., I was not digging up the root system. Starting May 25, seeing no clear decline in the counts, I began digging up the easy roots. Again, as the count failed to significantly decline, I have become more aggressive in my digging. The picture above shows the perpendicular rhizome--it is fairly easy for the vertical component to snap off, leaving the horizontal rhizome intact. While one web site claims that picking the stems will "exhaust the roots," they provided no evidence for this, or if true, how long it might take. The picture below shows how large these systems can become. In this picture, I show what was under a stone block--bindweed kept coming up from along the sides, and when I finally moved the block, this was underneath. The graph below that shows the count to date, along with a trendline. As can be seen from the trendline, the daily count decreases, but very slowly.

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Update: July 26, 2018 (7 weeks from the original post)

July in Indianapolis this year was very hot and dry. The various cover plants in my yard started to shrivel and I had larger patches of dirt. My twice-daily bindweed digs have significantly decreased, from the 50s at the beginning of July, to the 20s by the end of July. However, I have no way of proving it is the digs, or simply the dry heat, or even just a natural decrease for this time of year. I have caught each plant before they reach 6", mostly before 3", and no plants have flowered. I think I have increased my proficiency at digging out the white, fleshy rhizomes, although sometimes they are too deep to find efficiently, especially in the grassy areas. One artifact in the data, is that I realized I have been digging up 2 types of bindweed--field and hedge. The former has lighter colored and smaller leaves

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Update: Sept 4, 2018 (6 weeks from the last post, 15 weeks since the original post)

While the end of July brought daily dig totals down to the 20s, increased rain and cooler temperatures bumped them back up into the mid-30s for two weeks, finally falling into the mid teens by the end of August. The trajectory seems to continue a steady decline as seen in the most recent graph. Using a regression model since the beginning of the count (May 19; the regression equation is on the chart), I should have already dropped down to 10 plants per day on Sept 2, while in actuality I remain in the mid-upper teens as of Sept 4. However, the decline of the count seems to have leveled off around mid-July, so a revised equation, beginning from July 20, predicts that I should average 10 plants/day by Sept 15, and 5 plants/day by Oct 5. By that late in the year, it would difficult to differentiate the natural decline from digging the plants up versus the declining temperatures and shorter days. Finally, it seems worth noting, that as mentioned in my previous update, I have 2 types of bindweed, field & hedge, and that while initially I was almost exclusively picking field bindweed, now it's about half & half.

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Update: Oct 25, 2018 (7 weeks from the last post, 5 months since the original post)

This is the final report, at least for 2018. Over the last 10-days I have only found 3 bindweed. I would claim success, but my guess is that the significantly cooler temperatures and shorter days are the cause. I can only hope that by May of next year I will have far fewer bindweed than I had this year. At least one internet source claimed that the rhizomes can last for 3 years, which, if correct, means that I have another 2 years of digging up bindweed. However, about half-way through this year's experience, I began a concerted effort to dig all the way down to the rhizome. They are tricky to get, since they grow horizontally, and the plants snap off the rhizome with too much tugging, including the movement of digging down to get the rhizome, many of which were more than 6" below the surface. Here is the final graph for this year.