Irises: Treflan, Snapshot and Preen.... opinions please =), 0 by irisguy2

irisguy2 wrote:
The label on Preen or Treflan (used on farms) does not say it is recommended for iris. In my experience and with others here in Minnesota, we have found that especially with first year plantings, Preen doesn't do iris any favors when they are first planted. Growth is slower and sometimes we see the iris blooming on very short bloom stalks. I called up the technical support for a supplier of Treflan and he confirmed the active ingredient is not labeled for use with iris. Also note they have a version of Preen with added fertilizer. I assume this is not just a marketing ploy but may indicate that growth of other plants may also be slowed some by Preen. On the flip side, after my iris are established for a year, we do use Preen on some beds because it does help with some weeds (not thistles, dandelions or quackgrass which drive me nuts). This doesn't seem to retard the iris and it does keep some of the weeds from germinating. I haven't had much luck with mulch, especially peat moss which caused many rhizomes to rot in my garden. So it is just part of growing and enjoying iris for me that I get a lot of exercise through weeding. Also, like Laurief, I try to stay away from the chemicals when I can. In the spring I put a sparing amount of 10-10-10 fertilizer on the iris and Bayer's Merit (imidacloprid) for borer control. When I plant them I try to use a cup or so of alfalfa meal or pellets per rhizome to stimulate root growth and provide some organic fertilization. I think growing iris like many garden flowers requires some effort. For me it is worth it and I have quite a few.
Tim