There are many salvias (common name sage) of various colors throughout that area, and also blue ones. Your plant may be Salvia reptans cobalt sage (see images below) or S. transsylvanica (below). But without a picture we can't be sure. If you have a picture of the mystery plant, you can send it to plantinfo@nybg.org and we will try to positively identify it. Let me know if this helps.

See images below:

https://www.google.com/search?q=salvia+azurea&biw=1680&bih=949&tbm=isch&imgil=kqcu0p_GKwAJsM%253A%253B2DaHIApF38CLkM%253Bhttp%25253A%25252F%25252Fwww.wildflower.org%25252Fgallery%25252Fresult.php%25253Fid_image%2525253D8442&source=iu&pf=m&fir=kqcu0p_GKwAJsM%253A%252C2DaHIApF38CLkM%252C_&usg=__npwrkN6ecxcuKSkyBeNEdlgBiQA%3D&ved=0CH0QyjdqFQoTCNPnm7vsxMgCFYY3Pgod-CUC1w&ei=oc0fVpOTBIbv-AH4y4i4DQ#tbm=isch&q=Salvia+reptans+cobalt+sage&imgrc=adIXfI_NlvhmmM%3A

Salvia transsylvanica

https://www.google.com/search?q=salvia+azurea&biw=1680&bih=949&tbm=isch&imgil=kqcu0p_GKwAJsM%253A%253B2DaHIApF38CLkM%253Bhttp%25253A%25252F%25252Fwww.wildflower.org%25252Fgallery%25252Fresult.php%25253Fid_image%2525253D8442&source=iu&pf=m&fir=kqcu0p_GKwAJsM%253A%252C2DaHIApF38CLkM%252C_&usg=__npwrkN6ecxcuKSkyBeNEdlgBiQA%3D&ved=0CH0QyjdqFQoTCNPnm7vsxMgCFYY3Pgod-CUC1w&ei=oc0fVpOTBIbv-AH4y4i4DQ#tbm=isch&q=Salvia+transsylvanica&imgrc=TXOVP9PDPIE2DM%3A

Salvia is easy to grow with full sunlight, well-drained soil, that has added humus.

For tips on a variety of gardening topics, see our Plant Information Guides.
- Courtesy of NYBG Plant Information Service