I'm not going to be much help except to say they like a short dormancy period in the summer. Were you watering it a lot? I don't if you can save one that's rotting. Good luck!

Lynn

i suffered from this too. Basically the bulbs are susceptable to rot through bacteria...not much can be done, mine died but the other i have is thriving. Be careful though as it can spread so either throw away soil lily was in or plant something unrelated in it.

Hey there: calla lilies get a bacterial disease called Rot from a bacteria. Lack of calcium in the soil makes the plant more suseptible to the disease. Once the disease is present in the plant it must be destroyed. Nearby callas will likely be infected. Sandy
ISHS Acta Horticulturae 673: IX International Symposium on Flower Bulbs
VIRULENCE VARIATION IN 20 ISOLATES OF ERWINIA CAROTOVORA SUBSP. CAROTOVORA ON ZANTEDESCHIA CULTIVARS IN KOREA
Authors: H.R. Cho, J.H. Lim, K.J. Yun, R.C. Snijder, D.H. Goo, H.K. Rhee, K.S. Kim, H.Y. Joung, K.S. Kim
Keywords: Zantedeschia, Erwinia carotovora, calla, breeding, resistance, isolate
Abstract:
Bacterial soft rot caused by Erwinia carotovora subsp. carotovora is a major disease in Zantedeschia spp. Chemicals or modified cultivation methods only provide partial control of this disease. So highly resistant cultivars are needed to produce high quality calla flowers.
Experiments were conducted to screen for Erwinia resistance in Zantedeschia spp. by a leaf disk test. To determine variation for aggressiveness, 20 Erwinia isolates collected from sites at Jeonju, Pyeongchang, and Suwon were inoculated onto five Zantedeschia cultivars: including ÂWedding March as a resistant genotype, ÂLittle Suzy as a moderately resistant genotype, and ÂChianti as a susceptible genotype. Ecc NHRI-3 and Ecc NHRI-6 were the most virulent isolates among the 20 isolates of Erwinia carotovora subsp. carotovora tested. Within 25 Zantedeschia genotypes, including Z. rehmannii and Z. albomaculata, variation of Erwinia resistance ranged from almost completely resistant to extremely susceptible. ÂWedding March was the most resistant, while ÂGalaxy was the most susceptible.
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Well, my calla lily aethiopica went to see Jesus. Darn it. I'm determined to try some more, but will wait until spring.

Susan

Susan,

Around here, that's one of the bulbs that pops up in packages at the local HD in the fall. Keep your eye out for them!

Lynn

Cool - thanks for the heads up, Lynn. Usually the fall bulbs make an appearance sometime around mid-September here. A little too early to plant them, but if you want to get any kind of choice, you have to buy them then. That's why I like the mail order better - they always arrive in time to plant. But, I still buy from both HD and Lowe's anyway, and sometimes the local nurseries.

I grow a lot of lilies as well, orientals, asiatics, orienpets, species, etc. They can really be planted earlier than other bulbs like narcissus and tulips.

Susan

I've used Olive Leaf Extract (OLE) successfully to KILL Erwinia Carotovora (soft rot) in my Calla Lilly bed. It took one large plant before I knew what was going on. By the time I dug up the bulb it was pretty much all mush :( I saw that it was spreading to the next plant over, but on the tuber only, not yet to the bulb. I initially had taken hand fulls of lavender from my bush & shredded the leaves & bulbs all over the affected plants & surrounding soil & it seemed to slow the development of the rot. After some research I ran out & gathered a large bowl full of fresh green leaves from my olive tree (about 12oz of leaves) threw them directly into about 3/4 gal of purified water & simmered for 12hrs at about 180ð. I let it cool then strained off the liquid & applied it to the infected plant, its base & soil, and the soil where I'd removed the first infected plant that didn't make it. I then applied it all over the bases & soil of the rest of the callas in the bed just to be safe. I didn't loose another calla! The second plant that was infected I removed the infected tubers/shoots before application & discarded. It showed no further signs of the disease. I found the article citing OLE killing E. Carotovora here:
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CDEQFjAA&url=http%3A%2F%2Fwww.freescool.com%2Fwp-content%2Fuploads%2F2013%2F02%2FNATURAL-ANTIBIOTICS.docx&ei=jsaGUfLQD4f8iwK5p4CgDA&usg=AFQjCNGMOVR9KBRNiJMztrqll_zv_fV76w&sig2=yWrnPntpIjnZv9gBUliOyA&bvm=bv.45960087,d.cGE

I read about preparing your own extract here: http://www.jakesunbaked.com/2009/08/making-olive-leaf-extract.html

Callas and other tropical and subtropical Aroids get rot most often from being cold and wet. Erwinia just makes itself at home. Make sure to let your Callas dry before and during dormancy, and provide adequate drainage during their growing period. Never water c cold water or leave them out during extended cold wet periods.