Help With Trumpet Vines

My trumpet vines have never flowered. They receive at least 6 hours of sun each day and appear healthy, climbing a 10-foot trellis. How can I get them to produce the nectar-rich blooms hummingbirds love?

—Laurie Erickson, Prior Lake, Minnesota

Melinda: Trumpet vines need time and a little planned neglect to bloom. It takes several years for these climbers to reach mature flowering age. When trumpet vines won't flower, one of the most common culprits is fertilizer, which creates large plants with no blooms. Even if you don't apply fertilizer directly to the plants, they can absorb it from nearby garden areas or your lawn. To help control the vines' size, prune them in late winter. Overgrown plants can be trimmed to 12 inches above the soil.