From our perspective as gladiolus corms, our life cycle is driven by temperature and light. We are not true bulbs but corms—swollen, solid stem bases that store the energy we need to sprout and bloom. After planting, we send down roots to absorb water and nutrients. Our shoot then emerges, growing rapidly to form the characteristic sword-like leaves and the flower spike. The entire process from planting to bloom typically takes between 60 to 90 days, depending on the variety and environmental conditions. Once we have flowered and the bloom spike is spent, we begin the critical work of regenerating a new corm for the next season, drawing energy from the sun through our leaves.
To achieve a continuous display of your vibrant blooms throughout the summer, you must employ a technique called succession planting. This mimics a natural, staggered germination process. Instead of planting all of us corms at once, you should plant in batches, or intervals. This ensures that as one group finishes its bloom cycle, the next group is just reaching its peak. The goal is to have a non-stop sequence of flower spikes from early summer right through until the first autumn frosts.
The optimal schedule is based on your local climate, specifically the date of your last expected spring frost. We corms are tender and will not survive freezing temperatures, so planting must occur after the danger of frost has passed and the soil has warmed to at least 55°F (13°C).
1. **First Planting:** Plant your first batch of corms about two weeks before your last expected frost date. The soil is warming, and this gives us a head start. We will bloom approximately 60-90 days later, in early summer.
2. **Subsequent Plantings:** Every one to two weeks after the initial planting, put another batch of corms into the ground. Continue this rhythm for about 10 to 12 weeks. This creates a rolling schedule of development. For example, corms planted in mid-spring will bloom in midsummer, and those planted in early summer will flower in late summer or early autumn.
You can enhance this succession plan by being selective about which of us you plant. We come in many cultivars with varying days to maturity. Some early-season varieties may bloom in as little as 60 days, while large-flowered grandiflorus types often take closer to 90 days. By mixing these into your succession batches—planting early-bloomers in later batches and late-bloomers in early batches—you can further compress or extend the flowering window of each group, creating an even more seamless and prolonged display of color in your garden.
