I saw a short special on this garden. It was spectacular. I looked up some YouTube vids. They sell the various bulbs but are currently sold out. You need to start ordering in late December and January for shipment in June. In addition to specific bulbs you can buy curated collections. Hundreds of varieties.
They are the largest growers/hybridizers in the US.
Cooley’s Iris being the next in size,
and they closed their gardens 2-3 years ago.
At one time a visit to tour Schreiners Iris Garden
was #4 on my “bucket list”. However times change and they are
no longer in the top 10 of desires listed.