About six years ago, maybe longer several folks on Daffnet posted that using Round-up or glyphosate (same chemical) at 1/2 the normal strength could be sprayed right over the tops of daffodils when they were just sprouting. They assured folks that this would kill the winter grasses, chickweeds and other winter type weeds that thrive in naturalized fields of daffodils. They/several folks, had carefully spot treated various daffodils at various stages of early growth. This 1/2 strength gyphosate killed off all of the winter weeds and left their daffodils in a weed free planting. That spring these daffodils bloomed, foliage grew normally and these bulbs died down normally.
They shared this with the list and one person went and sprayed their entire 2&1/2 acres of daffodils with the same mix the second year. Again this was with great results as there were NO weeds at ALL and their daffodils bloomed great!
The problem was that the third year, after two years of spraying this field they ended up losing way over 95% of their whole field of daffodils. Not sure they are still on Daffnet. I sprayed “spots” in our drifts of daffodils and only once when the foliage was up but it took three years for most of these bulbs to weaken enough to die out.
I believe John Reed has experimented from time to time and some varieties or families of daffodils might be more or less resistant to “instant” death. I would be very careful with using Round-up or Glyphosate on anything with any dilution with green foliage.
Now Melissa brings up another worry. It would make sense as Round-up will get carried down into the roots of plants. As the tops die the chemical is still locked up inside the living and slowly dying roots. Fungi and other organisms will be eating and consuming the roots as they die and thus the chemical can get passed on before it gets a chance to totally break down into less harmful compounds.
Brutal heat wave in Texas, 56 days so far this summer with temperatures over 100*F, the forecast for the next 7 days are all over 100*F. Only 14″ of rainfall since December, only 4″ since April. We mowed off the front daffodil fields, our yard May 8 about 6 weeks after the last spring rains and it STILL looks like I mowed it last week. Only difference is it is brown and crunches when you walk on it.
2006 was hot and dry but this is just incredible to see all of the tree and landscape damage. Every city yard is losing one or more shade trees!
Keith Kridler Mt. Pleasant, Texas