These are Japanese Iris, a white variety that have been in the Jarvis Garden for years. I have split the fans many times and re-planted them around the property.
The bud comes up on a very long stem, well after the typical spring German Bearded Iris are long gone.
The White Japanese Iris start to show first. Here you can see that they are almost as tall as the common Road Side Day Lily.
A lavender smaller iris blooms next, and looks like the common
Siberian Iris, in size and form, which bloomed out weeks ago.
The bud of a deep purple Japanese Iris is third to bloom, which
opens up like this, and has a lovely yellow and white center. It stands a bit shorter than the white.
Finally the pale purple variety showed up.
All of these iris including
the Yellow Flag Iris, love wet feet. The whites can tolerate a dry location,
but no competing ground covers or other intruding plants. They will fade out and not bloom. Over time some of the whites were choked out by other plants and almost disappeared. I dug them out and re-planted them with more room and they came back with vigor.
The bloom period, of the Japanese iris is in between the Peonies and the Day Lilies.