Watering Bearded Iris

I've only been growing Bearded Iris for about 8 years, and have always been told by almost everyone that I talk to.... After planting and watering in, do not water them again. Some of the very generous folks telling me this, have shared iris with me... Most were very small rhizomes and leaf fans. I live in the hot dry climate of North Central Texas, and have often wondered how iris grown in rainy Oregon or parts of California survive based on this habit. Yet when I receive an order from those rainy climates their rhizomes are huge and healthy, making mine look quite puny. For three years one of my seedling beds bordered a neighbors yard whose sprinkler system watered about 1/3 of the bed. The others remained much drier. Well... the ones receiving the extra water had grown twice as large, were much healther with more blooms. So this year I am conducting a test, and keeping notes on how my irises fare under moist conditions. So far the ones that have been kept moist via a deep watering drip system are doing better, no soft rot. or crown rot, but nice green foliage that is putting out new leaves, instead of being burned to a crisp. I haven't had soft rot in quite a while, but have had 2 cases of crown rot this year on irises grown in dry conditions, and being invaded by bernuda grass. In fact, every iris with crown rot I've had, were being invaded by bermuda grass.

I would love to hear the thoughts of the more experienced.

Thanks, Dan

Well, Dan, I don't know that I am more experienced, but I do live in OR and have visited all those iris places. They all water their irises in the summer if we aren't getting rained on. I have all my irises in mixed beds with other perennials and annuals and I water them all with a sprinkler once or twice a week. It has never hurt any of my irises.

Thanks mgh... I sincerely appreciate the info.

Dan

I live in New Mexico and have a drip system on my iris and if I don't put an emitter on the clump, it may not bloom at all. It doesn't die, at least in a year. My climate is very dry ( 14 in. moisture per year.) We don't have Bermuda grass, praises be!
I believe your climate is wetter than mine, but clearly your iris do better with water than without. This year's AIS convention was in Austin -- which is probably more like your weather than mine. The number of surviving plants was appalling, though I am sure the gardeners broke their necks trying to keep them alive.
The explanation I was given by a well-known hybridizer and nursery owner is that iris can take heat and they can take moisture, but they can't take the two together. When the irises which were to be planted in Austin for this year's convention arrived in Austin, it proceeded to rain, pour, and even flood for an extended period of time. But the loss came when the rain quit, leaving the soil saturated, and it became very hot for a period of weeks. That is when many iris died. Interestingly the Louisiana's flourished.
The nice thing about a drip system is that you can turn it off. In your situation, I would put one in the beds not being watered by the neighbors. And I would turn it off for a few days when it rains good and hard, being especially careful to turn it off in hot weather.
In my cool dry climate, my irises would not grow at all well if I didn't water them. In your case, however, it sounds like some water would help, but I would be wary of too much water in hot weather.
But won't the water increase the Bermuda grass?

Alot of us growers in OR water during the summer because, remember we are DIGGING big time...and the ground no matter how nice it is gets hard on the surface and only the really big guys have equipment to dig, the rest of us do it by the same way you do...foot and shovel...dig a commerical 3 acre plot that has had NO WATER to speak of, makes it almost impossible...but give it a nice drink and you can. Remember too, OR does get alot of rain. This past April, May was the wettest, coldest latest snow in history here and June 1-15 was the wettest on history...this is why the season is so far off as well.

D

I'm certainly not more experienced, but I water my bearded right along with the siberians and the JIs. They are in the same beds. The only difference is I have the beardless mulched and the bearded are not. I make sure they get 2" of water a week in that bed. I like to do more, but it had been a very dry spring here. We are on sand.

I have never had a rhizome rot.

I'm sure a big factor is your drainage. On sand like we have, they are not sitting in the water, as they would on heavy clay.

If it's dry like it had been for the past 3 years, I water every 2-3 days...that's with several watering cans as I'm in an apt and don't have access to a outside water source. This year we finally have had some decent rain and I haven't watered much.

I also used to live in NM and had some huge TB iris that I used to keep watered about once a week--most of the spring and summer we were on water restrictions so you couldn't just water whenever you wanted.

I guess a lot would depend on drainage, heat and humidity. I'm not an expert so this stuff is just my experiences with growing iris. My iris bed in the front was mainly red clay (yay NC) that I removed in giant clumps down about 2 1/2-3 ft when I first dug up the unused bed. I then added soil, peat, compost, gypsum and some sand. I haven't had to do much to it since then except add a bag or two of compost/soil mix once a year usually in the fall before I start planting the spring blooming bulbs.

We have a semi watering ban here, only water in evening. We mainly water transplants including seedlings. However we don't have dry conditions at the moment, Nothing like TX & NM. We did have them last Aug. & hope not again. We do use a drip line.

Thanks everyone… I appreciate all of the comments. So glad to hear you folks are watering.

Pajaritomt, I sincerely appreciate the info… I will certainly take into account what the gentleman told you about iris not being able to take heat and water at the same time. Guess I’m going to find out what happens. I hope the problem in Austin was soggy soil for an extended period of time. I don’t have that problem here. I keep a very close eye on my irises and should notice any cultural problems before they get out of hand.

We are under water restrictions too, but can water anytime by hand, or a slow deep soak method. My beds are so scattered that I’ve never considered installing a nice drip irrigation system. My drip system is cheap sprinkler heads that I set to a trickle and move from bed to bed using four different hoses. My irises have never looked better now that that are being watered well.

The thing that has me puzzled about crown rot is where it has shown up… iris growing in dry soil that has Bermuda grass creeping in. Should mention that they were a bit crowded and should have been divided a year or two sooner. Anyway, the days are numbered for these beds, all the iris will be coming out soon and I will kill the Bermuda before replanting. Anyone had similar problems? The book… “World of Irises” says it’s more common in southern locations.

Thanks Again, Dan

First off, let me establish the fact that I am a rank amateur compared
to most contributors on this forum. I read everything I can find concerning
iris and will pass this along. You may not have crown rot but possibly
bacterial soft rot. Fans and single leaves falling down from the rhizome
are common in both cases. The obvious difference is bacterial soft rot
stinks to high heaven. Crown rot is a fungal disease according to 'The
Gardener's Iris Book' by William Shear. Both are symptomatic of too
much moisture or too little ventilation or a combination of both. The
disease is in the soil and Mr. Shear recommends solarization, a term
he uses for covering the empty bed with a clear plastic sheet and sealing
it down with earth. The hotter the sun the better it works. I tried it and
it cured my problems with fans rotting at the rhizome. One month in
July should do the trick. It doesn't hurt for your dug rhizomes to dry
during this time and it should help killing the fungus or bacteria on them.
Again, I am not an expert but I have "been there and done that". Hope
this adds something useful to the discussion.

Thanks for your help Oldgardenrose... I'm certain I'm dealing with crown rot. Yes, unfortunately I've had the opportunity to smell that wonderful scent of bacterial soft rot. Crown rot seems to start out as small, almost circular lesions, either on the side or back of the rhizome, just at the base of the fan. If caught early and treated, I've had success in treating and replanting. Later on the rhizome begins to soften in the area of the now larger lesion, and in the "too late stage" a white thread like fungus growth appears, the rhizome turns soft in the area near the lesion, (but remains firm otherwise with no smell) roots are dead, and it is virtually a goner. This is usually the time that the leaves yellow and fall over. However, I've dug some rhizomes with nice fans and the crown rot has already consumed the plant to the extent that I didn't try to save it. It's not a bad idea to check for the early indications when removing old leaves.

Narrowing the possibilities of what caused the problem though... possibly inadequate ventilation. These iris had become overcrowded, and since they were not some I couldn't live without, I procrastinated digging and replanting. The bermuda, an encroacher from my neighbor is so hard to get rid of, I know of no other way than to clear the beds and use herbicide.

The common factor in the crown rot was crowding, dry soil, and bermuda grass trying to take over the bed.

Thanks for the solarization idea. I certainly don't want to replant and still have the problem. You've been very helpful. Thanks so much for sharing your knowledge with me.

Dan

I have had bacterial soft rot. It was the year I installed my drip system and one area was lower than others and had too many emitters and iris in too small an area. I took the rhizomes out and dried them for a while in the sun -- the sun is very strong at 7,300 ft. I replanted the parts that were still good and they are doing fine now.
But other than that, I have had much nicer iris since I got the drip system. The first year it was in, I was totally amazed at the difference. It took me a while to realize that the difference was solely due to adequate water.
This year, I had to have part of the system rebuilt and everything had to live on the minimal water I could supply by hand. The iris are back to looking smaller. But the repairs have been made and things are perking up. I am hoping for another great year next year.
My soil is volcanic ash which isn't much different from sand. Water rarely puddles or pools anywhere around here. Not far below the stuff we laughingly call soil is solid volcanic ash, a kind of rock called tufa. The moisture goes down through the soil then runs underground downhill and is gone in a flash.
If we watered two inches per week, we would soon be bankrupt. We are only allowed to water at night and in the early morning, but other than that the only limit on our watering is financial, but the rate increases with the amount used.
It is a great climate for irises if you are willing to water a little, and though I hear arilbreds don't like to be watered in the summer, the only one I had that bloomed had gotten mixed in with the tall beardeds and got maximum water. It is so dry here, even arilbreds like water!
Roses do well here, too because fungus and mildew don't do well here.
Solarizing should work to get rid of bermuda grass as well. Solarizing kills everything including good soil bacteria. If you really want to do a thorough job, you plant a crop of mustard and when it is a few inches high, put your plastic over it and keep it covered for about a month. The gas from the mustard really kills things.
The problem with the bermuda grass, though is that there is always some more waiting to rush in to the newly cleaned up area. You have my condolences there. I hope I never have to deal with Bermuda grass again!

One last thing about iris diseases. Consider crop rotation. There
is a reason why farmers rotate crops year to year. Most veggies
have a caveat against planting the same type more than once in
the same soil without at least a year's rest. Each plant has some
unique diseases and predatory critters. Year after year planting
in the same location is an invitation to problems.

As far as you folks with limited water, consider recycling. Your
washing machine can use 75 gallons or more and it is relatively
clean going down to your sewage system. Pull the water drain
hose and send the water into a large tub or other container.
If I were faced with the choice of having the most beautiful flower
of all or some inconvenience, I would go for it. We have a 25,000
acre reservoir to draw from so I do not have the water problem.

Even with natural water we can't compete with west coast rhizomes--which is why some eastern nurseries send double plants. I know the few which we have sold will have to include more of the rhizome than further west.

This is a great thread. I've often wondered why the myth, "When in doubt, Don't water", has perpetuated through the years with irises, especially when it seems counterintuitive. Things can grow with less water, but don't we want all our flowers, and our bodies for that matter, to thrive? So, Water = good, according to this thread. I believe it, as I and many of you here are hooked on the Oregon growers catalogs.

Still, the myth survives in my own garden. I just installed soaker hoses in my iris bed with a dechlorinator attached and strung them mainly around my newly planted summer bulbs, glads & lilies, and wove them strategically through the bed avoiding the irises because the rain has been somewhat steady. I hear some of you say you water along with JIs and beardless and other plants. Should I water the bulbs and irises the same? Is there a strategy to laying soaker hoses around the irises? I suppose keeping them off the rhizomes makes sense, but as I am still so new to irises I suppose this thread is definitely making me rethink the crucial watering strategy.

Thanks zacattack and other contributors.

You know, I wish I knew about water in Kentucky. I think it is pretty wet there -- but I don't actually know. Realize where I live and water, we get 16 inches of rainfall per year, average. That isn't enough for much of anything! If you get 40 inches or so a year, you may just want to water in dry spells. Do you have a local American Iris Society branch? They would know.

We get less than 2 inches of rainfall a year; my bearded iris are on the drip system with daylilies and roses.....everything happy so far...very healthy and I had bloom from late February right up until last week when 2 of my TB's bloomed again!

I added the iris to existing raised bed 2 years ago...I also have iris in large pots on drip also.....

When I first became interested in irises I joined the local affiliate of the American Iris Society. I would recommend that anyone in love with irises checkout their local chapter. You can locate it here. http://www.irises.org/ais600localiris.htm I met some very nice folks there, and would still be a member had coaching my youngest son's baseball team not conflicted with my responsibilities as a member. HOWEVER... those are the folks that told me not to water. Maybe all didn't feel that way, but if they didn't they never spoke up.

If you aren't interested in joining a local affiliate, take a look at the American Iris Society. You're missing out big time if you're not a member of this organization. You can find out about them here. http://www.irises.org/

Hopefully we will get responses from some others, especially those in hot, dry climates. Thanks to all who have replied... this is interesting, and very important.

Dan

We just lay the drip lines on the ground. Used to pick them up during the winter, but when you get into your 70s take short cuts. As I mentioned we mainly concentrate on newly lined out seedlings. So far so good, but while we have sharp drainage we don't have a dry climate. Beardless can handle more water. I supposed different people in a single area do different things because of micro-climates.

You are right, zacattack, people don't always agree on how to grow iris, even in the iris society. But the people who are members of the society all have a lot of experience and won't lead you very far from the truth. As far as water is concerned, I am sure many knowledgeable iris lovers don't water in Fort Worth. I just know that in New Mexico it really helps and that too much water during the really hot spells can kill iris. I suspect they get a lot of water in Oregon, but I suspect it doesn't get very hot there.

it gets major hot here. Sometimes it rains all month. Sometimes not for a whole month. So erratic, but most problematic is the humidity and mildew problems, which so far don't seem to affect the irises. I am in clay, not heavy, and amended (with everything). I would guess about 60 - 70% of my first years 300 some odd irises did the Maiden bloom thing for me. All were planted throughout the summer last year and planting ended well before fall. We had a lovely, very wet spring. I loved my 1st irises.

Is there a sure way to tell by looking at the leaves if the iris is getting too much or not enough water? Do they droop or yellow?

Also if anyone has fought Japanese Beetles, (off iris topic) tell me how... please.... dmail is ok since it's not about watering irises.

Thanks again for the topic and the links and the help.

Too much water usually shows up on rhizomes which are food storage stems. Leaf spot can appear with not enough air circulation, we are getting some now so will have to thin some plants. I think when you water is as important as how much--settling transplants seems to be very important.

After two years of drought and just one or two a year lost to rot, I've got some serious rot problems. we've had a huge amount of rain and cold this spring, followed by a 100 degree heat wave the first two weeks of June. in my "most expensive" bed, I've probably lost half, mostly to crown rot. This bed has the least grade and is not in raised rows. Mama rhizomes are mushy, new rhizomes leaves are falling off.

I don't mulch, haven't needed to water yet this season. Am pulling out soft "feet," discarding them and sterilizing any viable "pups". spraying everything with fungicide. All other beds are steeper or in raised rows.

My condolences, bonjon. That has to be a heart breaker. It does sound like that deadly combination of water and heat. And clearly drainage had something to do with it, too. Too bad. Hopefully you will rescue many pups.

that's tragic. soooo sorry! and in the expensive bed too? really sorry bonjon.

Never fails...wet and then hot...this is sometimes what even can cause a grower to run out, because part was not affected and other part was or an entire stock, had 5 that lost everything, lucky only one had orders two never listed and one an older that no one ordered.

I feel for you. With the amount of rain we have had here and the extremely late season, we are running our tails off this year.

D

oh Dee! I'd send you some extra energy......if I had any!!! LOL

Thank you, but think all the growers will be in the same boat this year with the late season in CA and in WA OR

I think you have to find what works in your locale. I water until the new rhizomes show growth and then usually don't water them again. The large western rhizomes usually take a year to settle in here and then they grow smaller, tougher rhizomes that will withstand my summers. The only rot I have is with the new fat rhizomes usually in their first winter here. They have a tough time adapting to the constant damp continuous freeze/thaw that lasts for a few months. I think the constant freezing and thawing of the extra moisture in the cells causes the problems that lead to the rot I experience.

During last year's extreme heat and lack of rain, I only lost two large clumps of the dwarf Ruby Eruption. Everything else made it through.... although not everything bloomed this year.

Since we live on a hill, I grow my Irises & Daylilies in raised 8x8 and 8x4 beds. Our soil is caliche, and leaks like a sieve, so I need to water fairly often. I flood the beds briefly about once a week. I can't let the water run for long, as the nutrients all wash thru.
I have had these beds for about 6 years and only had soft rot once, when we got torrential rains for days, and then it turned off hot and cooked them.
I live in central Texas, and it gets very hot here...especially this year.

must be nice, that caliche.

we have acidic hardpan clay, and nothing "leaks" through. It just turns to "clay slip" until the sun bakes it back into brick. My irises are also on a slope, and we have to do 90% of our work with them preparing the beds. It takes months to break by hand (no rototiller made can do it), rototill, amend, rototill, amend, rototill, amend....well, you get the idea.

rot is not something I've experienced much of, maybe one or two a year. Until now. A bed made on not quite as steep a grade two years ago, in the worst of the drought, that was growing the irises so well I put all my most expensive ones there, turned out with normal rain it did nt drain well enough. I've lost 70% of my "mama" feet and many new pups.

Well, I don't know what caliche is like in Texas, but it is terrible in New Mexico. It is a thick layer of calcium deposit (essentially lime) that is hard like rock. It can be just under the surface or a foot or two down. To grow anything you have to break a hole in it with a sledge hammer or a pick, but it leaves the soil so alkaline that little will grow anyhow.
Among tales of bad soil, I think caliche and bonjon, you get to share the top prize.
My soil is not as bad, but it is almost non-existant. It is sand on top of tufa ( or tuff) which is essentially volcanic ash compressed to rock. It is a soft rock but you have to use a pick to make a hole in it in order to make a flower pot for your plant. Needless to say landscaping has been tough, but I don't think I qualify for the prizes that bonjon and caliche deserve.

paja - we don't dare make "flowerpot" for our plants. they do not drain and the roots do rot. Master gardeners constantly retrain newly transplanted people how NOT to garden here. LOL

They complain "nothing will grow" everytime I hear that, I turn around, point to a loblolly pine (there's always one within sight) and say, "what do you call that? seems mother nature does quite well here." CA people visit, think we live in a cotton pickin' state park!

Ya learn to garden on the surface with clay. That's why I like to grow the TB irises. the roots on mine never go too far down.

Well, one thing I have here is good drainage. The water soaks down to the tufa bed rock then runs underground down the hill -- I live on top of a Mesa. You really have to work to overwater here.

I would love that LOL!!!!!

It has its advantages, but I wouldn't mind just a tad less drainage -- I guess we are never happy. Lots of compost helps.

compost is always good.

pajaritomt, you have described caliche very well! It also has lots of comglomerate rock. It actually was once ocean floor, and is full of seashell fossils. I have a limestone Nautilus shell about a foot across, that was uncovered by my son while digging a hole for a tree.
It is much easier to dig when wet. To plant trees, we use a Ford tractor and a regular posthole auger, and dig as deep as we can. (about 4 ft)By amending the hole with lots of goodies, and then with a breaker bar, break the sides into the hole to loosen, and mix the so called 'soil", we can actually grow trees and shrubs.
I hand dig all my raised Iris beds, and have gotten the soil some better, with years of liveoak leafmold.
If you walk on the beds, it will again pack down to a brick, and you will need to amend and spade again.

Yep, that sounds just like our caliche only I don't know anyone lucky enough to have found a chambered nautilus in it. Maybe we just weren't looking close enough. Oak leaves are one of the best cures for caliche soil because they are very acid, but it would take a millenium of oak leaves to solve the problem permanently.
Actually I heard or read some where that the atmosphere of the earth was some noxious gas that contained huge quantities of calcium until some geologic change which caused it all to precipitate out of the atmosphere and into the soil. Back east where there is lots of rain the calcium has pretty much been neutralized over the millennia of decay of growing things. The west, having been dry still has alkaline soil for the most part.
I wish I could remember more of the story.

Sprinkle about a full tablespoon of garden sulphur in the bottom
of the hole before you plant your iris if the soil is alkaline. If
already planted just sprinkle the sulphur around the rhizome.
I believe ironite or irontite--can't remember the spelling, will
also help. Both are organic additives made by espoma or
epoma--again can't spell. I have used both on azaleas and
hydrangeas to add acid to the soil. Will probably take a
year or more to become useable to the plants.