Welcome.

Pebbles would be fine except...........when the iris need dividing they might be a nuisance and their absorbtion of heat from the sun.........??? Would sand work for a weed mulch? And yes, better to keep the mulch from covering the rhizomes.

I'm not familiar with Lamb's Quarters. But it sounds like it could be a problem by overtaking the iris. Any possiblility of lifting the iris and treating the bed with weed killer?

There may be helpful info by doing a search on mulch.

Thanks for the reply iris_gal. I see you are in California. I am betting there aren't any lamb's quarters there! I am including a link to a picture.

I don't think it ever gets hot enough here in Michigan for the rocks to be too hot for the iris but maybe I'm wrong. I just know that the lamb's qurters hold water like a cucumber and grow up close to the iris and keep them moist. Not good.

I have so many iris and am so new to iris gardening that I'm afraid to lift them and put down weed killer. I'm also afraid that the toxins would last in the soil for a while. I have the weed population low with constant tending but would like something to at least partially control the weeds. What do all of you iris grower's do? I know that someday, if I should be so lucky, they will spread and maybe I can shade out all the weeds but, for now, they are spaced far apart.

Thanks again for any and all replies.

Here is a link that might be useful: Lamb's quarters

After looking at many mulch related posts here, I see that you
gave me good advice, iris_gal. EVERYONE hates stone and say that it's a nightmare. So what do all of you iris growers recommend? Thanks.

I don't mulch my iris at all, so I'm no help. I just want to thank you for triggering a childhood memory of growing up poor in West Texas. In early spring, my father and us kids would search the bar ditches for young, tender lambs quarter, which he considered to be a great delicacy. We cooked it with salt pork.

You know, they say.."one man's poison is another man's
feast" as far as using lambs quarter for food.
When I mulch, I mulch everything. This is my 1st yr for
Iris, so am I understanding that I will have to be
careful about where I put the mulch aroud the Iris?

Iris rot if kept too moist. I lost some this year due to a wet spring...we are normally very dry. I do not mulch my iris for that reason.

I will never use pebbles in my flowerbeds because weed seeds get in anyway and it is the devil to remove the pebbles if you decide you don't want them.

My understanding is you can use Roundup with no lasting effects. I don't like to use chemicals but have had to at times to get rid of stubborn plants.

Good luck,
Peggy

Seagreen, glad you found more info. Thanks for educating me on Lamb's Quarters. I have bindweed (wild morning glory) and I have to use Round-Up for control. Nothing will eradicate it! I use it very carefully around iris. If the spray floats it can cause color distortion in the blooms. Which is sometimes interesting. But I use cardboard to shield the iris foliage and/or a paper cone to direct the spray only onto the bindweed. Or, I mix it in a glas measuring cup and put the tendrils of bindweed into the cup; then lay them away from iris.

I have read about 'dust mulch' and pretty much do that. I scruff up the top 2"-3" soil with my trowel. Since we have no rainfall for about 8 months, and when I water I do an overnight soak, the surface soil stays dry which helps to discourage weeds.

what is "dust mulch?"

I have a huge bed of irises under a mature oak. They have been growing amidst giant piles of big river rock that were put there by the original owner in the 80's, as "mulch" to keep weeds from growing under what was then a young oak. The rhizomes have forced themselves high enough in the rock piles so that rot has not been an issue. So as mulch goes, big rocks have worked fine, and I don't spend much time weeding in THAT area. But it could be that the oak shades out most weeds.

The rocks are heavy to move, but not difficult as pebbled or graveled areas would be.

I'm not sure I should write this for fear that I will be assailed by the experts! Having said that...here goes: I work at our local community college, and our grounds are exceptionally well maintained, lush, and diverse. I do not know what training the landscaping guys have, but I doubt that it is formal, in most cases. There is an entire bed of "Celebration Song," the Dykes Medalist from a few years back beside the building in which I work. This bed has about six clumps of "CS" growing in it--I don't know how long they've been there, but all are very well estalished.

Our grounds crew mulches EVERYTHING. That is their answer to weed control. They mulch every bed at the College. A thick layer of mulch (appearing to come from branches and leaves) is the answer to weeds at each of our campuses. "Celebration Song," under a layer of 3-4 inches of mulch each winter/spring, blooms too early (as would be expected)--this year in February, with several stalks freezing. However, once warm weather sets in, the remaining stalks pop up everywhere, with flowers blooming consistently. The six clumps began blooming in February this year but continued on through March, April, May and June. Four straight solid months of bloom. It was spectacular. "Immortality" is in bloom now and has been for a month--with 115 degree heat indices two weeks ago.

All I know is that mulch definitely does not hurt irises here--at least these two award winning cultivars (perhaps this is the secret?). I understand how rot can set in when moisture isn't alleviated--I have had it in my garden (in limited cases), but I don't see a correlation between mulch and rot in my workplace iris beds here in hot and humid South Carolina.

Again, I know it's not the *right* answer based on all that I've read, but it's the truth, so I'm offering it up for information purposes/debate.
Best of luck,
Mike in Coastal SC, Zone 8