Speaking of Hibiscus....

[IneverpromisedUarosegarden]

Hi Y'all~ I JUST signed up because I LOVE Hibiscus plants (all kinds) but I am not an expert in Hibiscus (any kinds).
Hopefully, someone out there can answer my question!
I'm talking about my tropical hawaiian hibiscus now: I bought them last summer and kept the small red bush on the west side of my house, and the yellow tree on the east side of my house. The red one only got sun in the afternoons/evenings, while the yellow one got sun all day. The red one flourished with blooms all summer while the yellow one didn't have any! I treated them both equally with watering & fertilizing. I brought them both indoors about a month ago, and the red one was placed in the same sun, only on the inside of the same window where it was all summer; it continues to bloom away. Meanwhile, I brought the yellow tree inside to face the east morning/early afternoon sun window, actually pretty close to where it was outside, only not as much sun. It actually sits in front of the heating vent too, by the way. I am counting about 20 blooms on it right now!!!
WHY is this happening? I thought they LIKE Sun & Humidity!!! How do I keep this happening all winter? Should I keep fertilizing or stop?
I wish I knew how to attach a photo; it is simply gorgeous! Oops, sorry...so is the red one--they are both beautiful!
I appreciate any advice, with grateful thanks!

[Eeyore]

Hi - check up in Plant Talk for comments.