I worked for many years in a large house museum in which the past owner was known for her greenhouses, and plants and flowers in her houses. Our board president was insistent that we maintain the tradition -- or the appearance thereof -- which made it easier to make good choices and pay for them. At that time, I believe that our main source was petals.com, or perhaps a precursor. I don't recall being unable to find any particular item, but given my limited knowledge on the subject, that would not be surprising. It took us several years to fund all the items we needed, but we had everything from ferns and palm trees, to orchids and herbs. The costs were considerable, but the products were excellent in appearance. The only failures I can think of were fading herb plants after many years, but they were placed in unfiltered sunny window spaces.
I should add that our visitors often commented on the beautiful flowers, which was gratifying. That also gave our guide staff the opportunity to speak further about the historical greenhouses (now gone) and the extant gardens on the property.
Best,
Bruce
A. B. MacLeish
Curator Emeritus
Newport Restoration Foundation
85 Lake Street
Cooperstown, NY 13326