|I'm not sure if this dahlia is an annual or a perennial. I got it as a gift in a large pot and it has been happily living on our balcony. I noticed last week that as the flowers begin to die, they were becoming covered with what looked like spider webs. I have not seen any spiders on the plant, but that does not mean they aren't there.
In the meantime, I did not look at it for a couple of days and today, the whole plant is quite dead and completely covered with spider webs.
Any idea what caused this?
|The webbing may very well be caused by spidermites, tiny little critters that in large groups can suck the fluids from plant tissues, causing the leaves and stems to collapse. Spidermites usually attack in late summer - they love hot, dry, dusty conditions. There's not much you can do to revive your dahlia, but I'd definitely prune away the dead material. Dahlias grow from tubers (storage organs which look similar to sweet potatoes) and the tubers are typically dug after the first frost kills the tops of the dahlia plants. The tubers are then stored in dry sawdust or peat moss in a cool, dark place to rest over the winter months and replanted in the spring. The dahlia tuber may very well be okay even though the top of your plant died down. After removing the dead foliage and stems, allow the pot to become dry then remove the tuber and store it until next spring. It might sprout for you. Hope so!|