Vased can indeed be used as an adjective. The productive suffix "-ed" can perhaps be added to any noun to form an adjective with the meaning 'possessing, provided with, characterized by (something)'. Vased is an example of an adjective formed within English by derivation, created by adding the "-ed" suffix to the noun vase. However, not all such forms will be found in dictionaries; some may be rare or even neologisms. Some of these forms may never have been used before and might not make much sense unless utilized by a creative writer.
Having said that, vased is listed as an adjective in the OED. It is one of the most credible and comprehensive dictionaries but subscription-based.
rare.
Ornamented or provided with vases.
1806 The stately yew-hedge walks, and vased and statued terraces.
W. Taylor in J. W. Robberds, Memoir William Taylor (1843) vol. II. 144
Oxford English Dictionary, s.v. “vased (adj.),” July 2023, https://doi.org/10.1093/OED/9347355860.
Vased flowers is an accepted usage also and it is used by floral shops as well. Here is an example usage I've found:
These vased flowers make beautiful additions to your home, office, or work space by adding vibrant color and fragrance. - phoenixflowershops.com
You can also find other derived words like dogged, blued, versed etc. in the OED and sometimes in other dictionaries. Some of these can be participle adjectives derived from verbs rather than nouns, and they can also be the past participle form of a verb. There are even colloquial derivations like MacGyvered.