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Growing Guide: How to Grow Gladiolus

Growing Guide: How to Grow Gladiolus

Gladiolus, also known as Sword Lily, is a stunning perennial flower that blooms in the summer. The name is actually derived from the Latin word for sword, ‘gladius’. The many varieties of Gladioli come in all sorts of colors, bright and soft. You’ll find them with single color, bi-color, and even tri-color petals. They look amazing planted in groups, and will definitely impress in any garden.

QUICK GUIDE

  • WHEN
    Plant in spring
    Bloom in Summer
  • WHERE
    Hardiness zone 8-11
    Full Sun
    Well-draining soil
  • WATER
    Water regularly if there’s no rain
  • WIDTH & DEPTH
    3-4” apart
    6” deep

woman planting gladiolus bulbs in garden

Arrival

When your DutchGrown Gladioli arrive and you can’t plant them immediately, it’s important to store them correctly: unpack them right away and put them in a dry place with plenty of air circulation, where the temperature is between 40 and 65 degrees Fahrenheit.

Garden & Container Planting

Gladiolus bulbs bloom in the summer, and can be planted throughout the season from spring to early summer. If you’re going for large quantities, you can stagger your planting over time so that you can enjoy their blooming throughout the whole summer. To thrive, they need to be planted in a spot with full sun, in rich and well-draining soil. A layer of mulch will help keep the soil moist. Plant the bulbs approximately 3 to 4 inches apart, and 6 inches deep. Plant them upright, with the pointy side up and flat rounded side down, to give them the right headstart to a successful bloom. Keep them well watered, especially in the absence of rain, ensuring they get the equivalent of 1 inch of rainfall per week. Gladioli can grow to heights between 48 and 60 inches tall.

Expect to see your flowers bloom in about 90 days from when the foliage begins to emerge overground. The tall stems are fairly strong, with sword shaped leaves. The flowers are funnel shaped with open, ruffled petals, and each flower spike can bloom with up to 20 florets. These blossoms open up one by one, starting from the bottom and working their way up to the top of the stem, so each flower will give you full color blooms for around two weeks. As they are such large flowers, they can sometimes become a bit top heavy. To prevent them from leaning, you can support them with bamboo canes, by tying them onto the canes gently to secure them. You can do the same with a larger area by using more bamboo canes and encircling the section. Alternatively, use them as cut flowers! To do so, you would cut the flower before it fully blooms, while the top florets have still not opened. This way, you are avoiding the leaning and heaviness altogether. Make sure to cut off the top bud as well, to slow down the rest of the buds from opening and get a lengthier bloom.

After they have finished flowering, remove the spent stalks and let the plant wither naturally. In hardy zones, you can leave the bulbs in the ground to perennialize. Once the plant has turned brown, cut it down to ground level, and it should come back again the following year. In non hardy zones, it’s probably best to treat Gladioli as annual plants. Plant new bulbs each year, or alternatively, dig up the bulbs and store them until the next planting season.

planting gladiolus bulbs in garden


How to plant Gladiolus in your garden:

  1. Start with loose, rich soil and a layer of compost, in a spot that gets full sun.
  2. Plant the Gladiolus bulbs about 6 inches deep and 3 to 5 inches apart, pointy side up.
  3. Water regularly, provide the equivalent of 1 inch of rain per week in dry weather.
  4. After the Gladioli have bloomed don’t cut off the foliage. Leave it until it’s completely withered and yellow, then remove.

How to plant Gladiolus in containers:

  1. Start with large, deep containers filled with multipurpose compost.
  2. Place the gladiolus bulbs on top, about 3 inches apart, and cover with more compost.
  3. Add a layer of gravel to finish off and keep weeds away.
  4. Stagger your planting in monthly intervals to enjoy a succession of blooms throughout autumn.
  5. After flowering, keep the bulbs in the containers throughout winter in a sheltered area, so they can bloom again next season.
Meet Ben, our Flower Bulb Specialist
Meet Ben, our Flower Bulb Specialist

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