Irises Aren't Blooming


Does mowing your Irises after they've bloomed cause them to not bloom again the next year? I'm not much of a gardener, which is probably obvious. We've had them planted for several years, and they bloomed pretty well for the first 2-3 years. My husband then mowed over them the last couple of years (after their blooming season), and now very few have bloomed back. Is there anything we can do now to help?


Hardiness Zone: 7a

Leah from Shelbyville, TN


Hi Leah,

Mowing them is fine after they are done blooming, but it is always best to wait until late in the season so the foliage has ample time to store nutrients for next year's bloom. Tell your hubby to hold off or even skip it this year and see if they come back strong next year. If not, then you need to look at other possible causes.

When irises fail to bloom it is usually due to nutrient deficiencies, inappropriate watering, incorrect planting depth, or overcrowding. In your case, you mentioned that your irises bloomed well for the first 2-3 years, but have failed to come back strong since. Have you divided them in the past few years? In not, I suspect they are in need of some breathing room by now. After a period of 2-3 years, irises start to grow into clumps and become overcrowded. They won't bloom well again until you give them a bit of breathing room.

Another cause to consider is whether a few years of mowing over them have buried the rhizomes under a bit of lawn mower mulch. If these are bearded irises, they should be sitting in the soil so the tops of the rhizomes are at or only very slightly below the soil's surface. If planted too deeply, you will see foliage, but no flowers.


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April 11, 20080 found this helpful

Mowing them should not damage them at all. Iris's are hardy. You may need to uncover the tubers however and pull some of them apart.

I am not a gardener but, I have Iris as they almost grow wild. The tubers seem to work there way out of the soil, so just brush the soil away. Look at the top bunch of tubers and see if they look eaten or mushy. Bugs will often times feed on the top bunch. Pull those off lightly. Then just cover the others up.

There always seems to be a lot more underneath and I get full blooms every year.

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April 12, 20080 found this helpful

If you are mowing down the tops, you are not allowing the tubers to "feed" and build up energy for the following year. The leaves are there to process the water and sun and feed the tuber, and if you cut them off, there is no food going in and eventually the tuber will just die back.

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April 12, 20080 found this helpful

We had iris that didn't bloom (maybe one or two would) but this was because the iris bulbs or tubers were VERY over crowded & needed to be thinned out... Are yours over crowded?

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April 12, 20080 found this helpful

I have tons of iris and I actually use the weedeater to take them down in the summer. Allow the leaves to stay a while after they bloom so they will get good "energy" to the tubers. The most improtant part of good blooming iris is that the tubers are exposed, I also live in TN so our weather is not so harsh. I always make sure that they are not too tight ( I actually just pull some out like carrots) then make sure that the tubers are not covered. When you first replant seperated iris you can take them down further so that they will set in but they eventually will rise up to the surface on their own just make sure you get all of the leaves and mulch off of them. If you do this you should see good blooms this year, mine bloom at varying times according to where they are in my yard. I have a lot blooming now but I will have another wave in the summer.

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April 14, 20080 found this helpful

I love iris !!

You may have them planted too deep.

Just barely put the risome in the soil......if there are those little "leg-like" pieces sticking out, put soil over those too. Leave the largest part of the risome just sitting on top of the soil.

If your husband is cutting over them, they could be sinking deeper than they need to be......covered by soil or even grass. Or by people walking on them.

They need those "green" tops ( leaves) to provide food for the risome after the bloom.This provides the food for next years blooms. By cutting those off, you won't get blooms next year.

Most folks cut the tall green leaves into a ^ shape, a Fan shape, or inverted V , in late July or August. Just use plain ole scissors to trim the leaves.This tidies up your flower bed. Yet there is enough green tops to provide the food necessary for next years blooms.

After enjoying the blooms, cut off the tall stems that the blooms were on...try not to scalp it...leave it as long as the leaves are tall.

Try not to allow the iris to send up a large round "pod" looking thing on the stem following the blooming. This is called "going to seed." And it will take a lot of the nutrients from the mother plant.

Iris will grow in very poor soil. They don't require much attention. After establishing them, you will need to divide them in a couple of years. Share them with your friends ...most everybody likes iris.

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April 15, 20080 found this helpful

When it happened to us, it was Iris Borers - a white grub that eats and destroys everything. We had to dig them up, destroy the borers we could find, sprinkle campfire ashes into the dirt before replanting them.

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May 15, 20080 found this helpful

I loosely braid my iris leaves and allow them to remain until they've done their job of storing energy for next season's blooms. I tie the ends off with strips made from leaf material. I do a few each day so it's not like I'm out there braiding leaves all day.

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May 15, 20080 found this helpful

Irisis are like tulips and daffodils and most bulb or tubular plants. They need the leaves to feed off of for next year's blooms. After they are done blooming just leave them alone for a month or 2 till they start looking dry,then cut them down with scissors to about 3 inches above the ground and they will do fine the next year. Also about every 3-4 years they should be seperated and thinned out. Good luck

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May 19, 20080 found this helpful

Just a note: Iris is toxic, so be careful what animals you feed those grass clippings to.

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May 20, 20080 found this helpful

My Dad ALWAYS mowed down the Irises. We would have to separate them every now and then. Then they wouldn't bloom too much the first year, but the second year they'd be fine. 45 years later I have some of those Irises from my parents house planted in my yard. Can't kill them!

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