"Red Flame" Flame grapes were developed in California. They are the result of a cross between Thompson, Cardinal and other grape varieties. Flame grapes are one of the most popular varieties along with Thompson grapes. These grapes are seedless, sweet-tart, and crunchy. The Red Flame was introduced in the 1970s, and it is now number two in the US market, A favorite of many homeowners and commercial growers alike.