There is never a reason other than cost not to try planting what you want unless the plant will spread wildly. Trying things even if you have been told it will not work is how new things are found. One of the reasons you probably do not see peonies is that the season in WDC is past for most peonies. Go to one of the local gardens and look for foliage.

I am in MD, 20 miles from DC. I successfully grow all types of Peonies: Tree Peonies, herbaceous, intersectionals. Virtually care free plants for me.

Thank you so much for your advice,

The peonies would be a gift for my sister - I intended to get a gift card for her.
(last time she planted several rose bushes who were all eaten by the deer and didn't do very well)

Alina, can you recommend a good local nursery or an online store ? - I was thinking at peonygarden.com from Ontario - They grow the old French fragrant peonies - the ones bred by Guerin and Calot , but I think it is always best to buy local.
Thank you

I bought my Peonies online because local prices are high usually. As far as I remember, Behnke's nursery has (at least, used to have) huge selection of Peonies (both their locations, Beltsville and Potomac).
For online sellers, check out this recent thread. Lots of useful info.