Anyone Ever Used Miracle-Gro All Purpose on Irises...?

If you did, what were the results? Did the rhizome rot, did it get leaf spot, etc? I remember back when I first started growing irises that I used some of the All-Purpose Plant food (I was a newbie at the time), and didn't have any problems with it. Do you think maybe it's a good thing to use every few years? Thanks in advance!

Sarah

Any even fertilizer is fine. You don't want to over-fertilize, because that causes a lot of leaf growth, which may encourage rot, but the fertilizer itself won't. Beardless iris tend to be heavier feeders, thus need more fertilizer, but all irises want a little fertilizer now and then! Miracle Grow is fine.

Sue

Sue

I've always been told to use either a 5-10-10 or 10-10-10. I think the Miracle-Gro All-Purpose ratio is 24-8-16. Won't that be too much nitrogen for irises? Thanks

Sarah

24-8-16 is really for foliage growth, not root and bud formation, so it is not ideal. I would stop using it and switch to a 5-10-10 or even a 2-10-10 would be better. You want the middle number the highest, if you have a choice. But, as long as you aren't using it several times a season, it is not going to kill iris -- you just won't get the bloom you're expecting. I like to use chicken manure tea or a local fertilizer called "Monty's Joy Juice" -- they have a "bloom" formula that I think is 2-15-10 that my iris love. They have a web site.

Sue

I use the LiquaFeed bloom booster by Miracle-Gro. It has a 12-9-9 formulation. It feeds evenly and I haven't had a problem with rot or leaf spot using it.

I haven't used the all-purpose food in almost 4 years. I got some 4-10-10 bulb food this spring, that was the lowest nitrogen fertilizer that Lowe's had to offer so I got it; haven't seen any negative effects.

I may have to try the Liquafeed bloom booster. Thanks to both of you for the tips!

I've read where large gardener iris growers use epsom salts and water as a fert. for their iris.