Queen Victoria Cardinal Flower Flopping and Stem Damage

A gardener's 'Queen Victoria' cardinal flower (Lobelia cardinalis 'Queen Victoria') grows tall but flops under its own weight, with only one stalk blooming by mid-July. Lower stems show chewing damage.

Staking for Support

This cultivar reaches 24–36 inches and can become top-heavy, especially in wind or rich soil. Stake early using bamboo stakes or a grow-through grid to keep stems upright.

Stem Chewing Culprits

Likely pests include slugs, grasshoppers, or caterpillars. Inspect at night with a flashlight for slugs; look for grasshoppers during the day.

Management

• Slugs: Beer traps, diatomaceous earth, or iron phosphate bait.
• Grasshoppers/caterpillars: Hand-pick or apply Bacillus thuringiensis (Bt) for caterpillars.
• Avoid broad-spectrum insecticides to protect beneficials.

Cultural Tips

• Plant in consistently moist, rich soil—cardinal flower loves wet feet.
• Partial shade in hot climates reduces flopping.
• Deadhead spent spikes to encourage rebloom.

With staking and pest monitoring, 'Queen Victoria' will reward you with brilliant red spikes all season.