The early iris are finished, and the later ones aren't blooming yet. The peonies are blooming, but almost finished - we think they were early this year, for I remember years when we thought they wouldn't make it for Memorial Day, and then at the last minute, they did. I think peonies are the traditional flower because they are the most reliable. Other than that, I have two kinds of allium blooming right now, but not much else.

Hello,
My grandma always had iris and peonies for Memorial Day. Both of these were blooming this year, you may need to add some early iris (flags is old fashioned name) to your plant list. I live east of Cedar Rapids.
Good luck,
Jo

I'm in zone 4, just a few miles from Hwy 20. This year, according to my journal, I cut on May 27 lupines, chives, salvia 'May Night,' cranesbill geranium 'Johnson's Blue', columbine 'Blue Star' and "William Guinness,' artemesia foliage, verbena clusters, 3 colors of peonies,later dwarf iris, and some later hybrid iris. To be safe, I cut the hybrid iris in bud a few days early and stored them in the basement so they'd still be in their prime for Memorial Day.

This was an unusual year. Some years my peonies aren't yet open for Memorial Day. I also have some Siberian iris which is a little later than my other common iris.

By June 3, I also had blooming small blue allium, campanula Canterbury Bells, yarrow, penstemon 'Husker Red', and dicentra 'Luxuriant' and 'Zestful.' I mention my June 3 blooms because those things might be good timing for your zone on Memorial Day.

I always take fresh flowers to the cemetery for Memorial Day, but I'm definitely a minority. With the wind and heat, my flowers don't last long, but they're a "labor of love" for those I'm remembering. Potted container annuals are another option, and then, if you can pick them up a few days later, you can enjoy them at home.