Weeding advice needed!

We are putting in additional beds, which is great! Now, however, added chore of more weeds to pull. We wonder if Round-Up has been used by any of you on daffodil beds…(IF the holes left by foliage are thoroughly filled in first?) What a pity if it should go straight to the bulbs’ roots themselves! We cannot use herbicides, as the creek below the beds leads to the James River, which leads to the Chesapeake Bay. It’s a great responsibility to prevent more damage to our waterways! Any safe weeding advice?

Janie

3 comments for “Weeding advice needed!

  1. To Janie, Roundup is an herbicide, so, for the reason you cited (damage to aquatic life), you are correct in not using it in your situation. If you search the web, you can find suggested alternatives. I have no idea how well they work. They include such ideas as burning the weeds, spraying them with soap, and spraying with vinegar. Web searches also show considerable debate about the toxicity of the inert ingredients to people, the side effects of the active ingredient on soil organisms, and the length of persistence of the active ingredient in the soil. I don’t know who’s right, but I do know that I did not find any information about consequences to daffodil bulbs.

    You asked if anyone has used Roundup on daffodil beds. In earlier years I have sprayed with Roundup in the winter before the daffodil leaves came up. I stopped doing that several years ago when Monsanto advertised the residual weed prevention capability of Roundup. It made me wonder what was persisting in the soil.

    In recent years I have been pulling weeds by hand or shearing off the tops of wild grasses to prevent them from reseeding. This is a lot of work and hasn’t been entirely successful. Last fall I tried generously scattering corn gluten meal over the beds. It is sold at my local nursery as a pre-emergent weed preventive. I’m pleased to say it was very effective at preventing new weeds from germinating. I did not have to do any hand weeding, and I did not have wild grasses springing up. The package says nothing about the fertilizer aspect of corn gluten meal, but I have since read that it supplies nitrogen. I do not know how much nitrogen, but the daffodils seemed to grow better — bigger flowers and bigger bulbs upon lifting. I also used a potassium fertilizer, so I cannot separate the effects of the two.

    Kirby

  2. You can use round-up if you remove all the foliage and cover the holes the foliage leaves to get down to the bulbs. However, be very careful. Getting round-up on most any dead or dying foliage will kill/damage the bulbs. I’m speaking from experience. However, I was once told by Dr. William Bender that the best technique to use on weeds is to pull them up. His words were “that’s what you have fingers for.”

    Clay

  3. Our fields are left to grow neck-high in summer cover, mostly of natives and a few weeds (or, mostly weeds and a few natives, depending on how you look at it). It is then mown with a tractor and a brush hog in mid-September, and then again in early October, sometimes a total of four times depending on the volume of ragweed and solidago. As soon as some re-growth appears, glyphosate (Roundup) is then applied directly over the tops of the rows throughout the field in mid-October, when it is still warm enough to apply, so that there will be little to no competition over the daffodil plants the following spring. We’ve done this annually since 2003 with no problems.

    Many of our daffodils leave large impressions or holes in the ground from their dying foliage that we do not cultivate over or fill in by hand–Mother Nature does this, and it takes most of the winter to re-fill the holes by freezing and thawing soil. Glyphosate applied over these holes where exposed bulbs are planted has never been a problem. It is my understanding, based on the chemistry and function of glyphosate, that it must come into direct contact with live plant tissue for translocation, and the cells must be chlorophyll for the glyphosate to have any efficacy. This is not true of other chemicals that can travel through the soil to the root systems of plants.

    Of note, I have to be very mindful around the tazettas and jonquils that are autumn emergent, as the glyphosate can be lethal. Years ago in the spring I did spray over the daffodil foliage, while it was still mostly green, and I wiped out the majority of my collection at the time. Lesson learned. In summary, I find that glyphosate is safe to use on the daffodils if used at the proper time and, like all chemicals, handled in a manner according to its labeling. Glyphosate and sodium hypochlorite (bleach, for disinfecting bulbs upon digging) are the only chemicals used with our daffodils on the PHS farm.

    Jason

    Jason A. Delaney | Missouri Botanical Garden | North Gardens Supervisor and Bulb Collections Specialist Post Office Box 299 | Saint Louis, Missouri 63166-0299 | United States of America |

Comments are closed.