I've been thinking long and hard and have figured out the cause of my damage and decided to make a new thread. See this thread for the pictures: http://davesgarden.com/community/forums/t/800087/
The ones that were affected were left outside of the greenhouses in the fall, and in the fall, I went around and sprayed Roundup on the weeds that were in the yard and around the bases of the plants. The four-year-old seedling was plunged and had weeds coming up around the base as did the others. I only sprayed directly on the weed and did not get any on the leaves or on the bases, and the Roundup is not supposed to travel through the soil, but I believe that it did indeed travel when it was carried to the roots by subsequent watering. I lost 8 plumerias because of this stupid mistake. I've read in the past that Roundup was safe to use around the bases of plumerias, but now I know that this isn't true. I hope that this helps others not to use it.
Roundup Damage
One more reason not to use any of that chemical stuff.... I have resisted heavily to the detriment of my fingernails!! Everyone says 'you will end up using Roundup' and somehow I cannot get my head around the fact that it can kill weeds and not harm your good plants in any way.
Clare, I'm sorry for your losses.
Thanks, Hetty. I usually pull weeds myself around the plumerias, but I guess I got lazy this year. So far, I've only lost 8, but I think there may be a few more about to show the damage. Roundup is supposed to stop growth, and it appears to have stopped all production of sap, causing the decline of the plumeria. I do remember, when I watered next, that there were suds on the ground around the bases. I think it got watered in to the root system. Please feel free to copy my post and post it on other groups to warn other collectors not to use Roundup. You were smart to never use it yourself. Thanks.
clare - are you 100% certain that absolutely no roundup, not even a microscopic amount got on the plumeria?
Yes, I made sure that there was no breeze or wind when I used it, and I held the sprayer nozzle about one inch from the weed before spraying. I was very careful to only hit the weed. I checked the label beforehand, and it said that it would not move through the dirt to the roots. However, when I watered next, there was a sudsy soapy type thing happening, and I remember thinking to myself that that can't be good, but I forgot all about it until all these plumerias started dying, and I was racking my brain about what could have happened, and then I remembered about the Roundup. I was perplexed about why these 8 were affected, and it was because they had weeds around them and were left outside of the greenhouses. I am 100% sure now that the Roundup was on the surface and watered in to the roots. I am so mad at myself. I should have known better, but there were so many weeds, and I wanted to save time by spraying them instead of pulling them.
Clare, If it was Roundup, and it did seep down to the roots, wouldn't the roots be burned from the herbicide? (Roundups motto use to be, kills down to the roots, I use to work for a chemical co.) The roots in your pictures looked healthy. Also in my experience with produce and herbicides (not tropicals), if plants do accidentally get exposed, the leaves show a halo effect. A yellowing of the outer edges of the leaf, with the centers staying green. Have you seen any of this? The other thing is that herbicide damage is usually seen right after the application, not months later (Not saying it CAN'T happen). I am not saying you're wrong, just curious.
Davie
clare that sudsy, soapy type thing you see happening is normal because there is a surficant (sp?) in roundup. i will have to test out the mode of transmission via roots. i've never had a problem with roundup. then again, i don't spray near anything i want to live because the spray get sairborne w/o a breeze. i will usually soak a sponge and then wipe down what i don't want if it is close to something i want. supposedly, they've test that to eternity to make that claim.
interesting point davie. i don't understand herbicides enough.
good luck!
Hi Guys! Thanks for your posts.
Yeah, Davie, I did see that with the leaves, but since all the other leaves were falling off too because of the cold, I thought it was just more of the same. I did not put two and two together when this occurred. They actually went limp first on the one that I can remember with that color pattern. Good observation on your part. I think the damage started showing up a few weeks later, but it is hard for me to remember what the time frame was. I've been so busy lately with work and stuff that I can't remember when I sprayed the weeds. You are right that the roots looked fine, but the death appears to be a slow one. Production of sap is stopped; nodes start to turn in and blacken; the inside of the trunks start to decay. I am sure now that the Roundup is responsible. The ones left out of the greenhouse were the victims and had the weeds.
Dete, that makes sense about the surfactant. My friend Kukiat said that his Magnolia suffered for years due to Roundup. He says that Roundup (Glycosate) is a systemic herbicide that can absorb into the root cells and finally kill the plant.
Clare, I am glad that you figure out what was going on with your plants.
Davie
Thanks, Davie. Thanks for your help with this. I just found my 'Rainbow Starburst' croaked. I had forgotten that I sprayed at the base of that one. I think that will be the last of the casualities. It is interesting to note that all one ones that were in 5-gallon containers died, but I'm sure that I sprayed some weeds in the 15-gallon container seedlings as well, but I've no casualties on those, and I think those all still have leaves. Maybe the bigger plumerias in larger containers could handle the Roundup better, not that I'll be using it again. Live and learn, I guess;-)