Introduction
Few flowers bring as much height and drama to the summer garden as the gladiolus. These tall, elegant spikes of bloom are a favorite for cutting and add a vertical element that few other plants can match. At Longfield Gardens, we enjoy seeing these vibrant colors return year after year in home landscapes across the country. It is a rewarding experience to watch those first green spears emerge from the soil in late spring, signaling a season of spectacular color to come.
While most gardeners look forward to the blooming season, it can be a bit confusing when you notice your planting beds have been disturbed or your favorite varieties fail to sprout. Because these plants grow from a starchy underground structure, they occasionally attract the attention of local wildlife and small insects looking for a meal. Identifying what might be nibbling on your gladiolus is the first step toward a thriving, beautiful display.
Protecting your garden doesn't have to be a stressful chore or a complicated puzzle. Most issues can be solved with a few simple, proactive steps that keep your plants safe without a lot of extra work. This guide will help you identify which critters or insects might be visiting your gladiolus and provide easy, practical ways to ensure your flowers reach their full potential. For broader growing advice, see this guide to gladiolus planting and care.
Identifying the Signs of Bulb Damage
Before you can choose the right solution, it helps to understand exactly what is happening beneath the soil or on the leaves. Gardening is often a bit like being a detective, looking for small clues to see how your plants are interacting with their environment. When a gladiolus doesn't perform as expected, the "evidence" usually falls into one of three categories.
Bulbs That Are Dug Up
If you walk out to your garden and find small holes in the soil with papery husks scattered around, you likely have a "digger." This is common in the fall or early spring right after planting. Squirrels and chipmunks are often the primary suspects here. They are naturally curious and are often attracted to the smell of freshly turned earth.
Bulbs That Never Emerge
When you plant your bulbs at the correct depth but nothing shows up by early summer, the issue is usually happening entirely underground. This is often the work of "tunnelers" like voles or gophers who move through the soil. However, it is also worth checking your soil conditions. In very heavy or wet soil, bulbs can sometimes struggle with drainage, which "Drainage" simply refers to how quickly water moves away from the roots. If the soil stays too wet for too long, the bulb may simply not grow.
Damaged Foliage and Flowers
Sometimes the bulb itself stays safe, but the plant faces challenges once it starts growing. If you see jagged edges on the leaves or the flower spikes disappear overnight, you are likely dealing with larger visitors like deer or rabbits. If the leaves look silvery, spotted, or streaked but aren't being eaten in large chunks, the cause is usually much smaller—likely thrips or other tiny garden insects.
Key Takeaway: Most garden visitors leave specific "calling cards" like footprints, tooth marks, or specific patterns of leaf damage. Observing these clues helps you pick the easiest and most effective way to protect your plants.
Wildlife That Eat Gladiolus Bulbs
In the world of gardening, the structures we call "bulbs" for gladiolus are technically known as corms. While they look like bulbs, they are solid storage organs rather than layered like an onion. These starchy packages are full of energy, which makes them an attractive snack for various animals, especially when other food sources are scarce.
Squirrels and Chipmunks
Squirrels are perhaps the most common garden visitors to interact with newly planted glads. Interestingly, squirrels don't always want to eat the corms. They are "investigative diggers." When they see you digging in the garden, they assume you are hiding a stash of nuts. They will often dig up a corm, take a single "test bite," realize it isn't a walnut, and leave it on the surface of the soil.
Chipmunks operate similarly but are more likely to actually eat or store small corms. Because they are smaller, their holes are more precise, often looking like a clean, one-inch tunnel leading straight down to where the bulb was placed.
Voles and Mice
Voles are small rodents that look like field mice but have shorter tails and heavier bodies. They are the "underground specialists" of the garden. Unlike squirrels, voles rarely come to the surface. Instead, they use existing tunnels made by moles or create their own narrow runways just below the mulch.
Voles can be quite fond of the starchy texture of gladiolus. If you have a beautiful row of glads and one or two suddenly tilt over or pull out of the ground with no roots attached, a vole has likely been nibbling from below.
Gophers and Groundhogs
In certain regions, larger burrowing animals like gophers can be a factor. Gophers are purely subterranean and can eat an entire planting from the bottom up. Groundhogs, on the other hand, are "dual-threat" eaters. They will dig for the corms in the spring, but they also have a massive appetite for the tender green shoots and flower buds once they emerge. You will know a groundhog is present by the large, distinct mounds of dirt near their burrow entrances.
Deer and Rabbits
While deer and rabbits don't typically dig for bulbs, they are famous for enjoying the "salad" portion of the plant. Gladiolus leaves are long and sword-shaped, and to a rabbit, the young shoots are a tender treat.
Deer tend to go for the flower spikes just as they are getting ready to bloom. You can tell the difference by the cut: rabbits leave a clean, 45-degree angled snip, while deer (who lack upper incisors) leave a ragged, torn edge on the foliage.
Common Insect Pests
Not everything that "eats" a gladiolus is large enough to see from your kitchen window. Several small insects can feed on the corm or the foliage, often causing the plant to look stunted or preventing the flowers from opening properly.
Gladiolus Thrips
Thrips are the most significant insect pest for this specific plant. These tiny, slender insects are barely the size of a needle tip. They feed by scraping the surface of the leaves and sucking out the sap.
The most important thing to know about thrips is that they can overwinter on the corms. If you live in a cold climate and dig your bulbs up for the winter, thrips can hide inside the papery husks and feed on the bulbs while they are in storage. This results in "corky" or rough, brown patches on the corm surface. When you plant them the next year, the plants may be weak from the start.
Bulb Mites
Bulb mites are almost invisible to the naked eye. They look like tiny, translucent grains of sand. These mites usually enter the bulb through small nicks or bruises. They feed on the internal tissue, which can lead to secondary issues like rot.
A plant with a mite issue will usually look very stunted and may have yellowish, sickly leaves. The best way to handle mites is to start with high-quality, healthy bulbs and handle them gently during planting to avoid creating entry points.
Caterpillars and Cutworms
Occasionally, you might find holes in the leaves or a young plant that has been "cut" off right at the soil line. Cutworms are nocturnal caterpillars that hide in the soil during the day and come out at night to feed. Zebra caterpillars are another variety that might enjoy the long leaves of the gladiolus, leaving behind distinctive chewed edges.
Aphids and Mealybugs
These sap-sucking insects are more common on the foliage than the bulbs. Aphids are small, pear-shaped insects that cluster on new growth. Mealybugs look like tiny bits of white cotton and often hide in the "axils," which are the spots where the leaf meets the stem. Both insects excrete a sticky substance called honeydew, which can lead to a dark, soot-like mold on the leaves.
How to Protect Your Bulbs Naturally
Protecting your garden should be a positive part of your routine, not a source of frustration. There are many simple ways to keep your gladiolus safe that don't involve harsh measures. Most of these methods rely on understanding how the animals behave and making your garden just a little bit less "convenient" for them.
Use the "Hardware Cloth" Method
If you have persistent issues with squirrels or voles, a physical barrier is the most effective solution. You can create a "cage" using hardware cloth, which is a wire mesh with half-inch openings.
- Excavate your planting area about an inch deeper than the recommended planting depth.
- Line the hole with the wire mesh, bringing the sides up to the soil surface.
- Place your corms inside the wire "basket" and fill it with soil.
- The roots can grow down through the mesh, and the stems can grow up, but the wire keeps paws and teeth away from the bulb itself.
The Gravel Trick
Many rodents, particularly voles and mice, find it very uncomfortable to dig through sharp, coarse materials. When you plant your gladiolus, you can mix a handful of crushed stone or coarse gravel into the soil immediately surrounding the bulb. This doesn't hurt the plant, but it makes the area much less attractive to a burrowing animal looking for an easy meal. This also has the added benefit of improving drainage in the root zone.
Scent-Based Deterrents
Animals have a very keen sense of smell, and you can use this to your advantage. Many gardeners find success using natural repellents that smell like things animals naturally avoid, such as garlic, peppermint, or certain predator scents.
One of the best "sneaky" ways to use scent is through companion planting. Most bulb-eating animals absolutely dislike the smell of Alliums (ornamental onions) and Daffodils. By interplanting your gladiolus among these "un-tasty" neighbors, you create a scent barrier that protects your glads.
Clean Up Your Workspace
This is one of the simplest wins in the garden. When you plant your bulbs, little bits of the papery husks often fall off and stay on the soil surface. These husks act like a "scented advertisement" for squirrels and chipmunks. After you finish planting, take a moment to clear away any debris and smooth over the soil. If the surface looks undisturbed and doesn't smell like a bulb, the squirrels are much more likely to walk right past it.
What to Do Next:
- Gather any fallen papery husks from the soil surface after planting.
- Smooth the soil or cover it with a thin layer of mulch to "hide" your work.
- Consider planting a few Alliums nearby to act as a natural deterrent.
Managing Pests During Storage
In many parts of the United States, gladiolus are not hardy enough to stay in the ground all winter. If you live in a region where the ground freezes (generally USDA Zone 7 and colder), you will likely lift your bulbs in the fall to store them indoors. This storage period is a critical time to protect them from "eaters."
Preventing Storage Rot and Mites
Once you have lifted your bulbs and allowed them to dry (or "cure") in a warm, airy spot for a few weeks, it is important to inspect them. Discard any bulbs that feel soft, hollow, or show signs of fuzzy mold. Healthy bulbs should feel firm and heavy for their size.
To prevent mites and thrips from feasting on your collection over the winter, some gardeners use a simple "dusting" method. Placing the bulbs in a paper bag with a small amount of garden sulfur or a labeled insecticidal dust can help keep the surface clear of pests.
Protecting from Indoor Rodents
Your garage or basement might seem like a safe spot, but mice and rats can find stored bulbs very quickly in the winter. Avoid storing your bulbs in open trays or plastic bags. Instead, use breathable containers that rodents can't chew through, such as:
- Small wooden crates with wire mesh lids.
- Old window screens stacked together.
- Breathable mesh bags hung from the ceiling.
The Temperature Factor
Keeping your storage area cool—ideally between 40°F and 50°F—is a great way to slow down any insect activity. Most insects become dormant at these temperatures, ensuring your bulbs stay in prime condition until it is time to plant again in the spring.
Simple Tips for Healthy Growth
A strong, healthy plant is always better at resisting damage than one that is struggling. By getting the basics right, you give your gladiolus the best possible start, making them more resilient to whatever the season throws their way.
Right Place, Right Prep
Gladiolus love the sun. To get those thick, sturdy stems that are less likely to flop over, aim for a spot that gets at least six to eight hours of direct sunlight. Good drainage is also essential. If you have heavy clay soil, planting your glads in a raised bed or a container is a great "easy win" to ensure the bulbs stay healthy and dry.
Planting Depth Matters
While it might be tempting to just tuck them an inch or two under the soil, planting depth is a quiet winner in the garden. For large gladiolus corms, aim for a depth of about 6 to 8 inches. Planting them deeply does two things:
- It provides better physical support for the tall flower spikes so they don't need as much staking.
- It places the bulb below the "dig zone" for most squirrels, who usually only investigate the top two or three inches of soil.
Water Correctly, Not Constantly
When the plants are actively growing and flowering, they appreciate consistent moisture. However, "consistent" doesn't mean "constantly wet." A deep watering once or twice a week is much better than a light sprinkle every day. This encourages the roots to grow deep into the soil, making the plant more stable and healthy.
One Change at a Time
If you notice something is eating your plants, don't feel like you have to try every solution at once. Start with the easiest fix—like moving a bird feeder away from the bed or applying a simple repellent. Wait a few days and observe. Usually, one small adjustment is all it takes to get things back on track.
Key Takeaway: Success with gladiolus often comes down to depth, drainage, and a little bit of "stealth" during the planting process.
Conclusion
Gardening is a journey of discovery, and learning how to share your space with local wildlife is part of the fun. While it can be a little surprising to find a missing bulb, remember that most garden visitors are just looking for a simple meal. With the practical strategies we’ve discussed—like deep planting, using wire mesh, and keeping your garden tidy—you can easily protect your gladiolus and enjoy their magnificent blooms all summer long.
At Longfield Gardens, we want every gardener to feel confident and successful. By focusing on a few basics like drainage and proper timing, you can create a vibrant landscape that thrives year after year. For additional guidance, explore All About Gladiolus.
Quick Summary for Success:
- Identify first: Look for holes, footprints, or ragged leaf edges to find the culprit.
- Physical barriers: Use hardware cloth or wire cages for persistent burrowing animals.
- Deep planting: Tucking corms 6–8 inches deep protects them from squirrels and provides better support.
- Good sanitation: Remove papery husks after planting to hide the scent of the bulbs.
- Smart storage: Keep lifted bulbs in a cool, rodent-proof container over the winter.
Protecting your gladiolus is a simple process that ensures your garden remains a place of beauty and relaxation. With just a few minutes of extra care during planting, you can look forward to a spectacular season of color.
FAQ
Why are squirrels digging up my bulbs if they don't eat them?
Squirrels are very curious and often think freshly dug soil means another animal has hidden nuts there. They will dig up a bulb to investigate, but since gladiolus aren't their preferred food, they usually just leave them on the surface after a single "test bite."
How can I tell if a vole is eating my bulbs?
Voles usually work entirely underground or in narrow tunnels just under the mulch. If you see a gladiolus plant that suddenly looks wilted or falls over, and you find the roots have been completely chewed away, a vole is the most likely suspect.
Do thrips live on the bulbs during the winter?
Yes, thrips can hide inside the papery husks of the gladiolus corms while they are in storage. To prevent this, make sure your bulbs are clean and dry before storing them, and keep them in a cool (40°F–50°F) location where insects are less active.
Will putting gravel in the planting hole hurt my flowers?
No, adding a bit of coarse gravel or crushed stone around the bulb is a safe and effective way to deter burrowing animals. It also helps with drainage, which is excellent for the health of the bulb, as long as the soil still contains enough organic matter to provide nutrients.
