This is a long shot, but thought I would try.

I would like to locate a list of herbaceous perennials by hardiness zone.

While I recognize most common garden plants, I don't know everything. And there are flowering gaps in my collection that I'd like to remedy for all season blooms. We have a very large area for planting and would like to fill it in, so space is not a problem.

So if such a list does not exist, I'm looking for suggestions.

Spring is easy with the tulips, grape hyacinths, etc. But there are gaps often for the rest of the season.

The gaps I have are

In June the Columbine, Bearded Iris and wild Iris versacolour bloom and not much else. A few Hardy Geraniums and blue Jacob's Ladder. Then there's a gap until the Asiatic Lilies begin. Starting in July the various bulb Lilies put on quite a show, then the Daylilies kick in.

Now in August, most Asiatic lilies are finished and the Oriental Lilies are blooming, but the Trumpet Lilies are still in bud. Echinacea is really kicking into gear. The three colors of Monarda just now blooming well, but might have bloomed earlier if I did not pinch out to encourage more bushy plants.

But the rest of the gardens look pitiful because they are all now finished and going into seed, or dying back, as in the case of the Bearded Iris foliage.

After the Oriental/Trumpet Lilies and the Echinacea finishes, we still have a few good weeks of good weather for something else to bloom and not look so sad. Usually all that's left is the annual self seeded Calendula and Johnny Jump Ups, but the tiny violas just disappear among all the tall stuff I grow. The flower gardens are pretty much finished before the leaves on the trees are full color in September.

I also have three types of Hardy Geranium, but they've all stopped blooming and I tried the suggestion of cutting them back to encourage new growth but they have not bloomed again yet.

So what are my options? What would fill in the gaps? Am I stuck going with annuals that I have to start from seed each year?