Cardinal Flower Pests

A healthy cardinal flower.

A healthy cardinal flower.

Also called red lobelia, cardinal flower (Lobelia cardinalis) is a short-lived perennial that grows up to 4 feet tall, producing bright red, two-lipped flowers that sit among glossy, oblong leaves. Cardinal flower is suitable for U.S. Department of Agriculture plant hardiness zones 3 to 9, where it thrives in fertile, moist soil. The robust plant is largely pest free, although slugs and snails can cause some ornamental damage. These pests may be particularly bothersome on cardinal flowers grown in shadier, wetter conditions, as this is their preferred environment.


Slugs and snails feed on flowers and foliage, causing irregular, smooth-edged holes. They travel using a muscular "foot" that leaves a long trail of silvery, shiny slime. They avoid the sun, coming out at night and during cloudy days. The brown garden snail causes the most problems in California gardens, according to the University of California Agriculture and Natural Resources, although slugs such as the gray garden slug and the banded slug can also cause damage.


Snails and slugs can be plucked off by hand and crushed, placed in sealable plastic bag and thrown away or drowned in a bucket of soapy water. Handpicking must be done at night with a flashlight, as they will not be active during the day unless the sun is covered by clouds. Flower pots, cups, boards or other manageable, shade-giving objects can be left in the garden as potential hiding spots for snails and slugs. Simply check the "traps" daily and remove and destroy accumulated pests. Though effective, salting slugs and snails is messy and will increase soil salinity.


To help prevent snail and slug infestations, remove potential hiding places such as plant debris, stones, weeds and wooden boards. Plant cardinal flowers away from hiding places that can't be removed, such as decks. Avoid watering from overhead, as wet leaves and flowers are more attractive to the pests. This practice also helps prevent fungal foliage diseases. If the pests are particularly rampant, consider putting a copper band around the flower bed. Snails and slugs dislike copper and will try not to cross it.


Snail bait is an effect method of killing snails and slugs. However, many brands contain the controversial ingredient metaldehyde. Metaldehyde is poisonous to cats, dogs and many forms of wildlife. Dogs are particularly drawn to the pelleted form, often with fatal consequences. Snail bait is the most common cause of dog poisoning in California, according to the website Some metaldehyde snailbaits also contain carbaryl, which kills beneficial garden creatures such as earthworms and ground beetles. If you must use a snail bait with metaldehyde, follow instructions carefully and keep the chemical off of other plants, especially vegetables.

About the Author


Photo Credits

  • Stockbyte/Stockbyte/Getty Images
Suggest a Correction