Dahlias and gladiolus are beloved summer and fall blooms, known for their vibrant colors, varied forms, and dramatic impact in gardens and floral arrangements. However, these tender bulbs and corms are not frost-hardy, and without proper storage, they cannot return to bloom the following year. Storing dahlias and gladiolus correctly is essential to ensure healthy growth, strong blooms, and longevity for your garden year after year.
In this article, we’ll provide a step-by-step guide on how to dig up, prepare, and store dahlias and gladiolus, along with tips on preventing rot, disease, and desiccation.
Why Proper Storage Matters
Dahlias and gladiolus are tender perennials:
- Dahlias: Grown from tubers, they are sensitive to frost and can rot in wet soil.
- Gladiolus: Grown from corms, they also cannot survive freezing temperatures.
Without proper storage, these bulbs and tubers can:
- Rot due to excess moisture.
- Dry out and lose viability.
- Become infected by mold or pests.
Expert Insight: Storing these plants correctly during winter ensures strong, healthy growth in the next season and reduces the need to purchase new tubers each year.
Step 1: Timing the Digging
The first step is to know when to dig your dahlias and gladiolus:
Dahlias
- Wait until after the first frost, when foliage begins to blacken.
- Frost-damaged leaves indicate the plant has entered dormancy, signaling the tubers are ready to be dug up.
Gladiolus
- Dig after the leaves yellow and die back naturally, usually 2–3 weeks after flowering ends.
- Avoid digging too early, as immature corms may not store well.
Expert Insight: Patience is key. Digging too early can damage immature tubers or corms, while digging too late may result in rot or frost damage.
Step 2: Carefully Dig Up Tubers and Corms
Proper digging techniques prevent damage and increase survival:
Dahlias
- Use a garden fork or spade to gently lift the tuber clump.
- Start digging about 12–18 inches away from the crown to avoid cutting the tubers.
- Shake off excess soil, but avoid washing the tubers at this stage to reduce the risk of rot.
Gladiolus
- Loosen soil around the corm with a fork.
- Lift the corm carefully, keeping the smaller cormels (baby corms) intact.
- Brush off loose soil, but do not wash corms until they are dry.
Expert Insight: Treat the tubers and corms gently. Cuts or bruises can lead to rot during storage.
Step 3: Preparing for Storage
Once dug, preparation is crucial to maximize shelf life:
Dahlias
- Cut back foliage to 2–4 inches above the tuber.
- Remove any damaged or diseased tubers; only healthy ones should be stored.
- Allow the tubers to air-dry for 1–2 days in a shaded, ventilated area.
Gladiolus
- Separate corms from old foliage and remove any diseased or soft corms.
- Allow corms to dry for several days in a well-ventilated space to prevent fungal growth.
Expert Tip: Ensure tubers and corms are completely dry before storage. Moisture is the leading cause of rot during winter.
Step 4: Choosing the Right Storage Conditions
Proper storage conditions are critical for long-term survival:
Temperature
- Store in a cool, frost-free location with temperatures around 45–55°F (7–13°C).
- Avoid warm or humid areas that encourage rot or premature sprouting.
Humidity
- Moderate humidity (50–70%) prevents drying out while avoiding excess moisture.
Light
- Keep tubers and corms in complete darkness, as light can trigger sprouting or photosynthesis.
Expert Insight: Basements, cellars, or unheated garages often provide ideal storage conditions.
Step 5: Storage Medium Options
Using a proper storage medium protects tubers and corms from rot, mold, and desiccation:
Dahlias
- Pack tubers in slightly damp peat moss, vermiculite, or sawdust.
- Ensure tubers are not touching each other to allow airflow.
Gladiolus
- Store corms in dry peat moss, sand, or vermiculite.
- Keep smaller cormels separate from larger ones to prevent crowding.
Expert Insight: Avoid storing directly on concrete floors, which can be too cold and may draw moisture from the tubers.
Step 6: Monitoring During Storage
Regular inspection prevents loss:
- Check tubers and corms every few weeks.
- Remove any that show signs of rot, mold, or shriveling.
- Lightly mist if the storage medium becomes too dry but avoid soaking.
Expert Insight: Early detection of problems can save the majority of your bulbs for the next season.
Step 7: Preparing for Replanting
As winter ends and spring approaches:
Dahlias
- Begin to reintroduce tubers to warmer conditions a few weeks before planting.
- Inspect for healthy roots and remove any that show decay.
- Plant after the danger of frost has passed.
Gladiolus
- Corms can be pre-sprouted indoors for 3–4 weeks to give them a head start.
- Replant outdoors after soil warms.
- Reuse smaller cormels to grow next season’s flowers.
Expert Tip: Pre-sprouting gladiolus corms indoors results in earlier blooms and stronger flowers.
Common Mistakes to Avoid
- Storing in a damp environment: Leads to rot.
- Ignoring damaged tubers or corms: Disease can spread to healthy bulbs.
- Planting too early in spring: Frost can kill tender shoots.
- Overwatering during storage: Moisture is the leading cause of bulb failure.
- Crowding bulbs or corms: Reduces airflow and increases disease risk.
Expert Insight: Proper attention to storage conditions outweighs all other interventions.
Benefits of Proper Storage
By following these steps, gardeners enjoy:
- Healthy, vibrant dahlias and gladiolus each year.
- Cost savings by reusing tubers and corms rather than buying new ones.
- A head start on early blooms and extended flowering seasons.
- Less risk of disease and rot in subsequent growing seasons.
Expert Insight: Good storage practices can allow dahlias and gladiolus to thrive for 3–5 years or longer, depending on variety and care.
Conclusion
Storing dahlias and gladiolus correctly is essential for long-term gardening success. By digging at the right time, preparing bulbs and corms carefully, using appropriate storage mediums, and monitoring during winter, gardeners can ensure strong, vibrant blooms for the next season.
Patience, attention to detail, and proper environmental conditions make it possible to enjoy these stunning summer and fall blooms year after year without the need for replanting or purchasing new stock. With proper storage, your dahlias and gladiolus will reward you with beautiful flowers that brighten your garden season after season, making your gardening efforts truly worthwhile.