Ask the Expert: I have a calla lilly that will not bloom
I have had this plaint for over 2 years also i have a peace lilly that wont bloom I had this palint for over 5 years they are both very health but wont bloom.  Kimberly

Reply:

It can take up to two year for a calla lily (Zantedeschia aethiopica) to produce blooms.  Of course, that all depends on how the nursery treated them before you got them.  We actually pot our calla lilies and make them bloom before we sell them to our customers.  At our nursery, we treat them with gibberellic acid which is a fungicide that also promotes plant growth and seems to stimulate the blooms.  However, this isn’t a product you can get over the counter. So it maybe that your calla lily was preparing itself for this year’s blooms.

Another factor that could be inhibiting blooms is the amount of sunlight the plants are receiving.  Calla lilies need at least 5 to 6 hours of direct sunlight or 10 hours of bright filtered light to bloom.  If your plants are in a very shady spot you need to move them to a sunnier area.  You might try fertilizing your calla lilies with a fertilizer high in phosphorous (p) the a couple of months before they bloom.  Try hi-yield bulb food which has a 7-8-5 (n-p-k) ratio or bone meal (0-10-0).   At the end of the season let the frost kill the foliage before you remove it.  Hopefully these suggestions will help and you’ll have lots of blooms this season.

Good luck and keep me posted