Gardening 101 | Slideshow

When is the best time to plant Summer Blooming Bulbs?


Before we can answer the question of when is the best time to plant summer blooming bulbs? We must determine what summer-blooming bulbs are! Online retailers like Holland Bulb Farms and Tulip World sell a variety of bulbs, perennials, fruit, and vegetable plants for planting in spring. Typically out of their assortment we consider summer-blooming bulbs to be bulbs that are planted in spring and bloom in summer. The most popular summer-blooming bulbs are:

Planting Time for Summer Blooming Bulbs

Proper planting time for summer-blooming bulbs will vary based on your location and different type of bulbs. Most summer-blooming bulbs are sensitive to cold soil, and below-freezing temperatures. Taking the weather into consideration in your area is the first thing to think about when planning your spring planting for summer blooming bulbs.

In addition to considering typical temperature trends in your area use your hardiness zone as a guide for when and what to plant. Hardiness zones are set by the United States Department of Agriculture. They are based on the minimum average low temperature a particular area receives. Plant and flower bulb hardiness zones are based on the lowest temperature they can endure for survival through winter. You can determine your hardiness zone by entering your zip code in the hardiness zone finder on the Holland Bulb Farms website here.

Zone Map

Planting Summer Bulbs in Zones 8-10

Gardeners in warm hardiness zones (zones 8, 9, 10, and 11) are typically able to start planting summer-blooming bulbs in mid-March or sooner if available. However, most online retailers and catalog companies don’t start shipping until the middle of March. Which makes March a good timeframe for planting to begin those areas.

Warm climate gardeners (or lucky people as I will refer to them from now on) can start planting summer-blooming bulbs in Mid-March. The planting season for these summer blooming bulbs like dahlias, gladiolus, callas, canna lilies, and caladium in warm climates can last through late spring.

Warm climate gardeners planting in late spring when the temperatures are on the rise will need to be more aware of keeping the bulbs watered once they see sprouts.  For people in places like Florida, California, Texas, Louisiana, and other warm hardiness zones, spring-planted summer-blooming bulbs are ideal for your locations and thrive in the warm and sometimes tropical climates.

Planting Summer Bulbs in Zone 7

Hardiness zone 7 covers locations in the middle of the United States. States like Tennessee, Oklahoma, New Mexico, Virginia, and North Carolina are in hardiness zone 7. Temperate areas like Oregon, Washington, and Northern California also have zone 7 hardiness in certain areas. These areas may get some winter-like temperatures on occasion, but in general, are a bit on the mild side. Once late March rolls around they are ready for planting. If you are in zone 7 and the weather isn’t quite cooperating by late March or your soil seems too cold hold off planting tender bulbs until later in April or early May. Tender bulbs are caladiums, cannas, begonias, and dahlias. 
Golden Glory Shade Collection

Planting Summer Bulbs in Zone 6

Hardiness zone 6 is one of the largest hardiness zones in the United States. This zone covers a large portion of the midwest, states like Illinois, Indiana, Ohio, and, Kansas, Massachusetts, and Connecticut. Even areas in Colorado, Nevada, and Missouri are in hardiness zone 6.

People in hardiness zone 6 are most likely to experience true winter conditions like snow, ice, and below-freezing temperatures. Therefore, gardeners in zone 6 should wait a bit longer to plant sensitive summer-blooming bulbs.  Even once spring appears to be in full swing, the soil may be a bit cold. Planting in cold soil can cause summer blooming bulbs to rot prior to sprouting.  Gardeners in zone 6 should wait to plant their summer blooming bulbs outside until the danger of frost has passed. Typically by mid to late May tender bulbs can be planted in the ground. Start tender bulbs indoors to get a jump start in the growing season.

Planting Summer Bulbs in Zone 5

Another large hardiness zone is zone 5, which is one of the colder zones in the United States. Gardeners in hardiness zone 5 should wait until around Memorial Day to get their dahlias, gladiolus, canna lilies, calla lilies, and caladium planted in the ground. However, if you have the capacity to start these tender bulbs in containers inside it is recommended to do so. Once the danger of frost has passed you may transplant the bulbs outside.

Planting Summer Bulbs in Zones 3 & 4

Zones 3 and 4 are smaller zones, but experience cold temperatures through winter and into the spring months. Summer blooming bulbs should be planted outside started in June. Again, if you are able to start your summer blooming bulbs inside before you can get to planting them in the ground I definitely suggest doing so.


Storing Bulbs and Perennials Prior to Planting

Many catalogs and online retailers of plants and flower bulbs will send you your items before you are safely able to plant them. They do this to stay ahead of schedule and ensure items are reserved through a pre-order.

If you receive flower bulbs, or perennial roots before you are able to plant them in the ground they store easily in dry, cool locations. Just open the box they came in, and make sure the packages have some air and the bulbs or roots will stay in good condition for several weeks. If you do get your items in advance of when you want to plant them, you can as mentioned above start them indoors. Starting bulbs and roots indoors can be helpful in having fuller plants with more blooms through the summer.

You may also have plans to plant bareroot perennials this spring for growth and blooms not only this summer but for many seasons to come! Typically bareroot perennials are not sensitive to frost and below-freezing temperatures. However, they can be a bit sensitive to cold and damp soils that can occur in spring. Therefore, you may not need to wait as long to plant your bare root perennials as you do your summer-blooming bulbs. However, be aware if the ground is moist and cold from snowmelt and increased rains you will want to wait until the soil warms up a bit before you plant.

When I plant bareroot perennials I always start them in old nursery pots. By starting my roots in pots I can control the soil temperature and moisture which is critical to starting new transplants. Even in May and June when it is safe for me to plant bareroot perennials directly in the ground I prefer to start them in pots. If you are able to start bare root perennials in pots it will be worth the extra effort.

Spring Will Be Here Soon

It may be cold and snowy where you are, or it may be warm and sunny. Either way, spring isn’t too far off. If you want a yard full of beautiful flowers this year, there is no better time than now to start planning and ordering your summer-blooming bulbs!

Need Gardening Help?

If you need any help with gardening or if you have plant-related questions or concerns, feel free to reach out to Jenny San Filippo. She can provide you with the knowledge and tools needed to succeed with your next project!

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