Iris are like daylilies, some multiply faster than others. If they are happy, they multiply quickly & need to be divided every 3 or 4 years. I mix my iris & daylilies together, along with daffs. My reblooming iris bloom in the spring & again in late fall, but I am told that if they are watered & fertilized, some varieties will bloom almost all summer in some areas. Personally, I prefer the reblooming ones, so nice to get color in the fall. Only problem is, several varieties bloom very late, & get bit by heavy frost.

Rita,
I also grow my iris and daylilies together. This is a very arid climate so the watering I do for iris is about the minimum for daylilies. You may not need to water at all depending on your natural rainfall.

On rebloom, like hardiness, it dependents on climate. Many that rebloom in warm southern states don't in northern, however, there are some that do rebloom OK in northern climates too. I'll provide a link to a Canadian vendor who has a short list of rebloomers that do well in their z4 garden. I recently saw an online catalog from another vendor that listed each plant's ability to rebloom reliably by the zone but I can't remember who it was now.

Rebloomers also need extra fertilizer and watering in the summer and don't cut back the foliage in late summer unless you are transplanting.

Here is a link that might be useful: Chapman Iris list of northern rebloomers

I can see I have more research to do before spending my money. Good advice from you both.

I would be afraid to try Bearded Iris in my daylily beds. Anything that does not want its tubers covered will never make it in those heavily mulched daylily beds.

I will start to look for northern rebloomers. Still, I have the same problem when looking at Iris pictures that I have when looking at daylily pictures. I see those gorgous flowers and I fall for a beautiful face. I have not seen any information where anyone lists the number of blooms like the daylily budcounts so I have no idea of how many flowers each TB Iris stalk really puts out.

I used to have bearded Iris that were over 50 years old if not older. They came with this house when my parents bought it and we moved in before I was 10 years old. Since I am 62 thats many years ago. I moved back into this house I grew up in after my mom passed away at the ripe old age of 93.

Anyway, those Iris, which never got any care whatever, are gone because of my garden renovations. Before I got the daylily crazies I did buy more newer bearded Iris but they all died out within two years. Now I realize its because I mulch heavily and they must have rotted because the iris tuber was burried under mulch instead of sticking up the way they need to do.

I am still thinking on the small long narrow garden section way in the front yard. I can go with the original staggered plan, or just go with a row of entirely bearded iris along the front. I have learned that mass plantings have the best effect. For instance, I had bulb lilies here for years but last spring put in way over 300 new ones. Almost all are in two mass plantings of a trench of 165 and another of 185 lilies planted close together. The effect was dazzelling in bloom.

Originally I thought I had to stagger them because when the iris were not in bloom there would be no color and its the garden right off the sidewalk by the street so it needs to look good. But with the planter directly behind it all planted in daylilies, there should be plenty of summer color and the roses bloom on and off plenty too. So I do not think lack of blooms would not be a problem.

I can always plant spring bulbs and get plenty of daffs and tulips along with the iris so earlier spring should bring plenty of color to bring it into bearded iris time. Plus I have groused about not having the perfect place for bearded iris because of the heavily mulched beds. A more perfect spot could not be found. So its up in the air, I am thinking about which way to go.

Rita,
While its true that bearded iris don't like heavy mulch, usually they will just refuse to bloom if the rhizome is covered unless they are actually too wet. In this climate they are subject not only to extreme cold winters but also sun scortching and extreme drought so many growers do cover them with about an inch or less of mulch.

Another possibility for why your newer ones died is that like many daylilies, the newer iris are hybridized and selected in milder climates. Many of the older iris came out of Nebraska (hybridized by the Sass family) and similar climates so were very hardy.

Like daylilies, you may need to look for a supplier who grows iris proven to be northern hardy.

The iris I had bought were locally store bought from displays. I was dissapointed but I know more now and am sure that I will do better this time. I am going to mail order my iris this time from reputable iris farms, like I do with my daylilies now. So far I am still looking as iris ship later in the year, I have time.

My rebloomers are planted with my once-bloomers, and are treated identically. Perhaps I'd get better rebloom if I had the separate and gave them a little extra food and water (recommended for rebloomers) but I don't, and have gotten good rebloom from several cultivars. (I don't have many.) Growing in zone 5, these have been good for me:
Zurich (white TB)
St. Petersburg (white TB)
Baby Blessed (yellow SDB)
Harvest of Memories (golden-yellow TB)
Golden Immortal (yellow TB, more modern form than HoM)
September Frost (white TB)
Mariposa Autumn (purple & white plicata)
Clarence (med. blue-violet washed white)

And 2 more SDB's come to mind, that I know have rebloomed nicely in a friend's NE Ohio (zone 5) garden:
Velvet Echo (velvety dark violet)
Shout (white w/violet spot)

Hope this helps!
Diana