You asked for blue? Well here is a HUGE list of BLUE garden plants along with general care requirements.
- Annual lobelia (Lobelia erinus), full sun to partial shade, to 9 inches tall
- Borage (Borago officinalis), full sun to partial shade, to 24 inches tall
- Browallia (Browallia speciosa), partial to full shade, to 24 inches tall
- Chickling pea (Lathyrus sativus), full sun, to 3 feet tall