From what I remember, the main character is a young boy who goes to live with his dad who lives in a rundown mansion or something similar. When he gets there, he explores a bit and finds out about dragons and befriends them, and throughout the series he has to protect them and help a rare one hatch or something. Hardly anyone knows that the dragons exist too. From what I remember, the cover had a pretty realistic dragon in the night sky, maybe with a moon behind it.
Is this the Pillage series by Obert Skye...? There are three books in the series, with the first having been published in 2008 and the last in 2012.
Here's the Goodreads synopsis and cover for the first book, Pillage (2008):
Upon his mother's death, fifteen-year-old Beck Phillips is sent to live with an eccentric uncle he had never met in a remote manor house, where he learns that his family suffers from a curse that allows him to make plants grow on command and dragon eggs hatch.