When and How to Plant Summer Bulbs

Flowering bulbs in hand to be planted for summer

The Spruce / Phoebe Cheong

When you think of "summer bulbs," these are flowering bulbs that grow and bloom during the summer instead of spring. These bulbs tend to be tender perennials that can't survive the cold, snowy winter, so they are either grown as annuals or are dug up, stored, and replanted every year. Some summer bulbs also flower in the fall, depending on your region.

Summer bulbs include begonias, caladium, cannas, dahlias, gladiola, gloriosa lilies, elephant ears, liatris, nerines, oxalis, pineapple lilies, tuberose, and tigridia. Some of these are tubers, corms, and rhizomes, but for purposes of planting and storing, they're grouped under the term "summer bulbs."

Read on to learn more about the ideal time to plant summer bulbs and how to care for and maintain them when they are in the ground and stored over winter.

When to Plant Summer Bulbs

Summer bulbs need warm weather and warm soil. Unless you live in a region where the ground doesn’t freeze, you have to replant tender perennial summer bulbs every spring. Unlike spring-blooming bulbs planted in the fall, summer bulbs need to be planted in the spring.

Once the soil has dried out and warmed up to about 60 F or higher, it’s time to get summer bulbs in the ground. A rule of thumb to remember is if it’s time for your tomatoes to go outdoors, it is also time to plant your summer bulbs.

Many people also like using a calendar as a general guideline for planting. The following suggested dates are based on broad estimates based on hardiness zones in the U.S. Actual dates for planting will fluctuate based on the severity of winter (unseasonably warm or cold), how rainy it has been, and if the threat of frost is gone. If you had an unseasonable warm winter, then the ground is likely to thaw sooner, and you may get your summer bulbs in the ground sooner. Too much rain or oversaturation of the ground can cause your bulbs to rot. Your best bet is to get an inexpensive temperature probe to test the soil temperature and keep watching the weather projections for your area before you plant your bulbs.

  • Hardiness zones 8, 9, 10, and 11 (Florida, California, Texas, and Louisiana): Mid-March, sometimes sooner
  • Hardiness zone 7 (Tennessee, Oklahoma, New Mexico, Virginia, North Carolina, and parts of Oregon, Washington, and Northern California): April or early May
  • Hardiness zone 6 is one of the largest hardiness zones in the United States (36 states and Washington, D.C., including parts of Illinois, Indiana, Ohio, Kansas, Missouri, Colorado, Nevada, New Jersey, Massachusetts, and Connecticut): Mid to late May
  • Hardiness Zone 5 is another large hardiness zone in the U.S., one of the colder zones in the United States with 32 states (including parts of Iowa, Nebraska, Illinois, Indiana, Michigan, New York, Pennsylvania, Vermont, and New Hampshire): Around Memorial Day
  • Zones 3 and 4 are the coldest U.S. zones (parts of Alaska, Montana, North Dakota, South Dakota, Minnesota, Wisconsin, Vermont, New Hampshire, and Maine): June

Another option is you can get tender bulbs like dahlias, gladiolus, canna lilies, calla lilies, and caladium started four to eight weeks in pots indoors in a sunny, protected location such as a greenhouse, sunroom, or enclosed porch. Transplant them or bring them outside when ground and climate conditions are right.

Most summer bulbs are later bloomers, blooming in mid to later summer or early fall. Gladiolus, caladiums, begonias, and calla lilies can start blooming as early as mid-summer. Meanwhile, canna lilies, agapanthus, dahlias, and elephant ears may start their bloom period in late summer or early fall. Bulbs contain a reserve of stored energy, and once they get started, they grow quickly. They perform well when other flowers and plants have passed their prime.

Illustrative chart showing the best time to plant summer bulbs according to hardiness zone

The Spruce / Jiaqi Zhou


Most bulbs need a well-draining site to prevent molding and rotting. Amending the soil with compost or manure will help the bulbs grow, bloom, and store energy.

The package the bulbs come in often tells you the planting depth for your specific bulbs. You usually plant bulbs about three times as deep as their diameter. So if you have a bulb that is two inches around, you would plant it six inches deep. You would plant a three-inch diameter bulb about nine inches deep.

Another option is you can also plant summer bulbs in pots. Growing plants in containers is a great way to give them the extra warmth they need since pots retain more heat. Most summer bulbs need at least a 10- to 12-inch pot. You can plant two to three bulbs of calla lilies, caladium, and begonias in one pot—a couple of inches apart—while you can plant five gladiolus bulbs together, about an inch apart in an 8-inch pot.

Flowering bulbs placed in soil in rows closeup

The Spruce / Phoebe Cheong

Care and Maintenance

  • Watering needs: Although you don't want to plant in soggy soil, once your bulbs are in the ground, you should water them well. Then make sure they get regular water, but allow the soil to dry out between waterings.
  • Weeding: Like caring for other plants, keep the area weed-free, especially while the plant is getting established. Weeds will compete with your plants for nutrients, and the weeds often win.
  • Fertilizer: If you intend to dig up and store your bulbs over the winter or if the bulbs are perennial in your area, give them some supplemental fertilizer every month or so during the growing season. If you are growing your bulbs as annuals, feeding is not necessary, but a mid-summer dose of fertilizer will give them a second wind. Any balanced fertilizer that is low in nitrogen is fine.
  • Storing bulbs over winter: To store summer bulbs, place them in a cool, dry location such as a storage room or basement. The temperatures should stay between 45 and 50 F. Never let the temperature drop to freezing. Allow the bulbs to lay out on a tray separately to dry (for about two weeks), then place the bulbs in peat moss, vermiculite, sawdust, or shredded paper in a ventilated box. If it's very dry in the room, place a bowl of water near them to slightly increase the humidity around the bulbs.


The best time to harvest bulbs for the winter is when all of the plant's foliage has died in the fall before the first frost. Trim the foliage to 6 inches and gently dig the bulbs out of the ground. Take care to not damage the bulbs; discard any bruised or damaged ones.

White watering can pouring water into raised garden bed with summer bulbs

The Spruce / Phoebe Cheong

Buying Bulbs or Pre-Grown Bulbs

So if you're ready to have summer bulbs growing in your garden, then what's next? You need bulbs! Or, you can get a head start and buy a summer bulb plant that has started growing in a nursery or greenhouse.

Ordering bulbs online is a great option to have them delivered right to your home. Inspect the bulbs when they arrive and make sure none have turned dark brown, black, or mushy, indicating mold or rot. They may appear dry or "dead" when they arrive, but they are not; they are dormant. If they appear completely shriveled, it has desiccated and is likely dead. Contact your supplier if you notice rot or desiccation.

Another excellent way to have summer bulb flowers is to buy them pre-grown. You can often find potted caladiums, elephant ears, begonias, and others for sale at the nursery starting in the spring.