“How warm do I have to keep my house for a tropical hibiscus? I live in Maine, and it gets quite chilly!” Question from Valerie of East Andover, Maine

Answer: Your tropical hibiscus (Hibiscus rosa-sinensis) will grow best in temperatures between 55ᵒ and 85ᵒ Fahrenheit. If temperatures drop below 50ᵒ F, it will require some protection. Inversely, temperatures above 100ᵒ will cause it high stress, but that’s certainly not a problem you will have. Tropical hibiscus also grows best with a higher level of ambient humidity.

Just give you plant warmth above 55ᵒ, good humidity, and it should grow well until your spring days grow warmer. Also, be sure not to overwater hibiscus growing at cooler temperatures. Less water is needed under cooler growing conditions, and too much water can cause root rot.

Happy hibiscus growing!

Jessie Keith

Black Gold Horticulturist