Answer: Unfortunately there really isn't much you can do to slow the plants down. You might be able to toss some mulch over the tulips if a very cold night hits while the buds are showing, but in general they are very cold tolerant. While buds and blooms may possibly be zapped by frost, most shrubs and trees will take that in stride and still manage to leaf out and be okay. As far as the roses go, as long as there is air circulation the cones do provide a certain amount of insulation from the heat as well as cold. Once the forsythia blooms you can begin to remove some of their protection. You might want to check on them occasionally however to be sure they are okay.
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