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morgang_gw

What makes 'spring bulbs' spring and 'fall bulbs' fall?

morgang
17 years ago

Cleaning the garage this week, I found the brown paper bags with some bulbs and corms I bought last fall: tulips, oriental lilies, bleeding heart, bearded iris, astilbe. The iris and tulips are labeled for fall planting, showing the fall months on the back diagram. But the packages are identical to the spring bulb packages I just bought that show the spring months for planting.

1. What makes the difference?

2. Can I plant any of these now, wait for full, or are they toast?

Comments (3)

  • cranebill
    17 years ago

    Hi morgang,

    Except for the tulips, everything you've mentioned can be planted either in spring or fall. I need to add some important qualifications, though. Lilies should ideally be planted early to mid-fall to allow them to get their roots going before the deep freeze: fall planting yields better bloom. Also, it's not good to hold over unplanted lily bulbs for planting later: they should be planted while they're still quite fresh as they are susceptible to rot if too moist and dessiccation if too dry. Bearded iris rhizomes also benefit from fall planting, but are tougher in storage than lily bulbs. Bareroot astilbes and bleeding hearts are usually offered in spring, and although astilbes may also be found at retailers in fall, both are best planted from spring stock in spring and should not be held over for planting until fall as they will dry out and likely die. Tulip bulbs always need to be planted in the fall (unless they have been given a long precooling treatment by the vendor) because they need a good eight to ten weeks of chilling winter temps.

    Notwithstanding my comments about tulips, my advice is to plant them anyway - plants in general have a way of defying received wisdom regarding what they're supposed to do. Your tulips are not likely to perform well, so maybe plant them where you won't mind if they produce only foliage and a few stunted blooms. My neighbors had a fair show of tulips they belatedly planted one spring: the blooms were not as good as they would have been if they had planted the bulbs on schedule, but they were still nice.

    By the way, my understanding is that "spring bulbs" are planted in fall to bloom in spring; "fall bulbs" are planted mid- to late summer to bloom in the fall (not too many of these but autumn crocus and lycoris come to mind), and "summer bulbs" are usually (not always) tender plants that bloom in summer but can't withstand temperate winters, and so are usually brought indoors or discarded in areas colder than Zones 7-8. It's confusing.

    cranebill

  • raul_in_mexico
    17 years ago

    Ok, here´s the deal:

    1.- some spring bulbs need a period of cold in order to bloom, others can survive if planted in warmer climates and even multiply but they won´t bloom ( like many types of daffodils ), no cold period, no blooming.

    2.- some will not survive the hot temperatures of places that don´t have a "cold" resting period ( tulips DIE when planted in zones 7 and above ).

    3.- some bulbs will not go dormant and they can´t be harvested until dormant, which usually happens in the fall ( like lillies )

    4.- some bulbs multiply during the summer, growers allow the bulbs to form more bulbs for the market ( like german irises ).

    5.- most summer bulbs are tender and can´t survive freezing temperatures ( reason why dahlia growers don´t ship to the north during the coldest months of the year )

    So for example for your area, tulips, crocus, daffodils, lilies, all those will survive the freezing temperatures and bloom the next spring; dahlias, callas, cannas, gladiolas have to be lifted or they won´t survive the winter. German irises can be left in the ground, they survive the winter, don´t need a cold resting period in order to bloom, they tolerate very well heat, german irises are in practical terms all around bulbs, plant and forget about them they survive almost anything ( except too much water for an extended period of time ).

  • greenguy1
    17 years ago

    The whole "spring bulb" and "fall bulb" labels can be confusing. Tulips/Daffodils/Crocus/Hyacinth and the like, for example - planted in the fall, but people generally call them spring bulbs because that's when they bloom.

    However, the bulbs you see for sale in the fall are the hardy plants that generally want a cold period and will survive the winter and come back year after year, like those I mentioned above.

    What you see for sale in the spring are the non-hardy bulbs and bulb-like plants that will not survive in the ground over winter, such as Dahlias, Caladiums, Elephant Ears, Glads, Cannas. Some people treat these as annuals, and others lift the roots and store them from year to year, replanting each spring. Of course, as you move further south, eventually you reach a zone for each of these things where it will be hardy outside through the winter, i.e., they will be perennials - for Glads and Cannas, we're probably talking US zone 7, a little further south for the other things mentioned. Still, they are traditionally sold in the spring because the merchants want to cover the whole range of both cold and warm zones with one sales period.

    The confusion comes because there are a lot of things you see packaged bare-root like bulbs which are for sale in both fall and spring - such as the Astilbe and Bleeding Heart you mention above and lots of other perennials. As you say, the packages look identical with the same contents and one shows fall planting and the other shows spring planting. These are the things that are successfully divided and transplanted any time they are dormant, which is from fall until they start to grow in the spring, so they are sold at both times. Lilies are a true bulb that is also in this category - the bulb never goes completely dormant, so they can put out new roots any time you transplant and will do well either spring or fall planted. As Cranebill mentions above, the best results for any given growing season will come if you get them in during the fall before, but I have always had success with them in the spring.

    Also, as Cranebill mentions above, if in doubt when spring comes, plant it anyway. The worst that can happen is that it won't grow, which is ASSURED if you don't plant it.

    - Steve