Where I live north of Boston Rosa rugosa grows wild on the shore. Typically they have a large burst of bloom in late spring and then have more or less constant scattered light rebloom for the rest of the summer.

I can't be certain of this, but given that this rose species' native range is northeastern Asia (Japan, Korea, Manchuria, far eastern Siberia) I have a suspicion that this rose may not tolerate hot summers well.

All of my rugosas with the exception of Agnes rebloom and I never deadhead as I want them to form hips. How old are your roses and what varieties do you have? What area of the country are you in zone 5? Do your roses get plenty of rain or are you in a dry area - and do you supplement water? Aare they planted in full sun? More info would help us to help you. :-)

Mine all rebloom. I do keep them deadheaded but I don't just snap the old bloom off. I cut it off just below the flower cluster after the last bud is done.
A few older Rugosas that are not hybrid only bloom once or repeat very little.

Rugosas do not like the heat and even good rebloomers will shut down in hot summers. But some varieties bloom better than others, so without knowing what you have, no can tell.

We are in Chicagoland. We do get hot and humid here 90+ F degrees and down to below 0 for extended periods, this year 14 below!

Maybe I will try not just snapping off the flowers, and cutting like the suggestion said. I do have older varieties: Hansa and Blanc double de coubert. Maybe they need a pruning?

But I also have wildberry breeze and wild spice and neither have much rebloom.

They are in mostly full sun, 8+ hours a day. I will try supplementing with water. I usually do not do this unless it is VERY hot (above 90). I also fertilize after the first flush but this does not seem to work.

Do the "explorer" varieties which I noticed have rugosa parentage, have more rebloom?

Thanks for your help.

I had Therese Bugnet, a hybrid rugosa which did rebloom in spite of my hot and dry location. Mrs. Doreen Pike also seemed to want to rebloom, although it also didn't like the heat. I think the Pavement series is supposed to rebloom fairly well.

Ingrid

Schneezwerg, Fru Dagmar Hastrup, Jens Munk, Blanc Double de Coubert, all the Pavement series, Jessica Lauren, Marie Bugnet, Sweet Cecilia, and Therese Bugnet, all bloom well for me with repeat all summer well into fall.
Of the above, Jens Munk is the best. It always has many blooms.
Jens Munk
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Blanc Double de Coubert
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All repeat best when kept deadheaded, and do so well into fall. This could be due to my zone 5a climate. All are planted in full or almost full sun.
Except for Jens Munk, the Explorers are slow to repeat
for me.

Thanks for the lovely pics. I should mention that my soil is quite heavy and tends to clay. Also alkaline.

BDC is at least ten years old. grafted onto Dr. Huey. My Hansa 3 years old or so, grafted onto multiflora. I did have a polareis which gave slight rebloom but I had to remove because it was WAY too large for the space. No one told me it was a rambler!

I just like the rugosas so much as they are the only roses I can depend on to come back after a harsh winter 100% cane hardy. This year, I fear I will have some casualties with my other roses with that 14 below and 2 feet of snow we had.

In Sweden Louise Bugnet is perhaps the most popular rugosa after Hansa and the common red single. It blooms continuously from June till the first frost. It is one of the shorter rugosas, about the same size as Fru Dagmar Hastrup. A taller Explorer with the same colouring, white blooms with red buds, is Lac Majeau, a favourite of mine.

Perhaps the alkaline soil is a factor? Here in southern NH I have moderately acid (the blueberries love it, I do next to nothing to them) and I think the rugosas like it too.....

I grow Jens Munk and Henry Hudson, both explorers, never deadhead Jens Munk it always reblooms in Aug. Henry Hudson is always in bloom no deadheading, remove spent blooms...I do water in dry periods I don't really feed them very much at all...Grew Hansa for a few yrs. good spring flush, light repeat here..