# What causes the flowers to come back every spring? **URL:** \ **Category:** Factual Questions\ **Created:** [April 26, 2021, 12:27am UTC](https://boards.straightdope.com/t/what-causes-the-flowers-to-come-back-every-spring/940764 "2021-04-26T00:27:53Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![ekedolphin](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ekedolphin/32/10003_2.png) [@ekedolphin](https://boards.straightdope.com/u/ekedolphin)\ **Post date:** [April 26, 2021, 12:27am UTC](https://boards.straightdope.com/t/what-causes-the-flowers-to-come-back-every-spring/940764/1 "2021-04-26T00:27:53Z")
It’s been a _long_ time since school for me, and I was never good in science, so forgive me if I’m asking a fifth-grade question. When grass and flowers die at the start of winter, they’re dead, right? So how do flowers and grass come back in the spring? I assume trees just hibernate or something. ---
**Author:** ![ekedolphin](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ekedolphin/32/10003_2.png) [@ekedolphin](https://boards.straightdope.com/u/ekedolphin)\ **Post date:** [April 26, 2021, 12:28am UTC](https://boards.straightdope.com/t/what-causes-the-flowers-to-come-back-every-spring/940764/2 "2021-04-26T00:28:21Z")
Title should read “What causes the flowers to come back every spring?” ---
**Author:** ![Jackmannii](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jackmannii/32/311_2.png) [@Jackmannii](https://boards.straightdope.com/u/Jackmannii)\ **Post date:** [April 26, 2021, 12:31am UTC](https://boards.straightdope.com/t/what-causes-the-flowers-to-come-back-every-spring/940764/3 "2021-04-26T00:31:49Z")
"Many perennials lose the parts of their plants that are exposed as the temperatures drop. The roots in the ground move as much of the the water in their tissue’s cells into the surrounding ground as possible. With less moisture in the plant’s cells, a certain amount of freezing and thawing can occur without rupturing those cells. Also, sugars and salts in those roots act as a natural antifreeze. By lowering the freezing point of the water in the plant’s cells, it allows them to survive lower temperatures." > **[How Do Perennials Survive a Northern Winter?](http://ourlittleacre.blogspot.com/2010/01/how-do-perennials-survive-northern.html)** > > While much of the nation sits in a deep freeze, here I am, in my nice warm family room, looking out at a sunny blue sky day. The ground is c... ---
**Author:** ![kenobi\_65](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kenobi_65/32/13178_2.png) [@kenobi\_65](https://boards.straightdope.com/u/kenobi_65)\ **Post date:** [April 26, 2021, 12:43am UTC](https://boards.straightdope.com/t/what-causes-the-flowers-to-come-back-every-spring/940764/4 "2021-04-26T00:43:51Z")
The sorts of grass that we use as lawns in the U.S. usually doesn’t die in the winter months; it goes dormant. If an area on your lawn _doesn’t_ turn back to green in the spring, then it probably did die over the winter. (Also, grass will go dormant during drought conditions, even in the summer.) > **[Why is Grass Brown in the Winter? | Gecko Green](https://geckogreen.com/why-is-grass-brown-in-the-winter)** > > Is your grass brown in the winter & you're not sure if it's dead or dormant? Learn about the difference here & tips on caring for your lawn in the winter. ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [April 26, 2021, 1:00am UTC](https://boards.straightdope.com/t/what-causes-the-flowers-to-come-back-every-spring/940764/5 "2021-04-26T01:00:30Z")
Annual plants die every year or so. The species survives by producing seeds that can grow new plants every year. Some of them complete the cycle in less than a year, and another kind of plant does it in 2 years. Obviously annuals will be limited in size because each plant completes it’s life cycle in a short time. ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [April 26, 2021, 1:11am UTC](https://boards.straightdope.com/t/what-causes-the-flowers-to-come-back-every-spring/940764/6 "2021-04-26T01:11:33Z")
Putting @TriPolar comments about “_Annual_” plants together with what @Jackmannii almost said, “_perennial_” plants sacrifice parts of themselves each winter while the overall plant survives living in slow motion until spring when it regrows fresh leaves and flowers for the next warm cycle. So sort of vaguely like animals hibernating. If you imagine animals having limbs fall off and regrow fresh each year. Trees are perennial, but so are many common garden plants and flowers. ---
**Author:** ![Jackmannii](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jackmannii/32/311_2.png) [@Jackmannii](https://boards.straightdope.com/u/Jackmannii)\ **Post date:** [April 26, 2021, 1:22am UTC](https://boards.straightdope.com/t/what-causes-the-flowers-to-come-back-every-spring/940764/7 "2021-04-26T01:22:32Z")
> [@LSLGuy](#): > > Putting @TriPolar comments about “_Annual_” plants together with what @Jackmannii almost said, “_perennial_” plants sacrifice parts of themselves each winter while the overall plant survives" Not that it matters terribly, but what I quoted about perennials closely matches what you just posted, i.e. above-ground tissue being lost to cold while the less vulnerable rootstock/corm/tuber/bulb survives. No “almost” about it. Some perennials do maintain viable above-ground tissue even through harsh winters and in the case of hellebores for example, push buds and flower during mild spells. ---
**Author:** ![Darren\_Garrison](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darren_garrison/32/92_2.png) [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)\ **Post date:** [April 26, 2021, 1:29am UTC](https://boards.straightdope.com/t/what-causes-the-flowers-to-come-back-every-spring/940764/8 "2021-04-26T01:29:28Z")
> [@TriPolar](#): > > Obviously annuals will be limited in size because each plant completes it’s life cycle in a short time. Some of them can get to be 10-15 feet, though. ---
**Author:** ![engineer\_comp\_geek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/engineer_comp_geek/32/504_2.png) [@engineer\_comp\_geek](https://boards.straightdope.com/u/engineer_comp_geek)\ **Post date:** [April 26, 2021, 1:33am UTC](https://boards.straightdope.com/t/what-causes-the-flowers-to-come-back-every-spring/940764/9 "2021-04-26T01:33:51Z")
> [@ekedolphin](#): > > Title should read “What causes the flowers to come back every spring?” Fixed. ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [April 26, 2021, 1:38am UTC](https://boards.straightdope.com/t/what-causes-the-flowers-to-come-back-every-spring/940764/10 "2021-04-26T01:38:54Z")
> [@Jackmannii](#): > > No “almost” about it. Yeah I didn’t say that as well as I might have. Sorry. You gave the full story on perennials and Tripolar on the annuals. But nobody explicitly brought out the idea that plants come in those two broad classifications that have very different winter survival features. That was the “almost” part I tried, and failed, to clearly point to. ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [April 26, 2021, 1:54am UTC](https://boards.straightdope.com/t/what-causes-the-flowers-to-come-back-every-spring/940764/11 "2021-04-26T01:54:11Z")
This little tidbit about the [Molecular Genetics of Annual Plants](https://en.wikipedia.org/wiki/Annual_plant#Molecular_genetics) is interesting: " In 2008, it was discovered that the inactivation of only two genes in one species of annual plant leads to the conversion into a perennial plant. Researchers deactivated the SOC1 and FUL genes in Arabidopsis thaliana , which control flowering time. This switch established phenotypes common in perennial plants, such as wood formation." ---
**Author:** ![purplehorseshoe](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/purplehorseshoe/32/2996_2.png) [@purplehorseshoe](https://boards.straightdope.com/u/purplehorseshoe)\ **Post date:** [April 26, 2021, 1:57am UTC](https://boards.straightdope.com/t/what-causes-the-flowers-to-come-back-every-spring/940764/12 "2021-04-26T01:57:59Z")
> [@ekedolphin](#): > > When grass and flowers die at the start of winter, they’re dead, right? Let’s start here. By “grass” you mean a turf lawn, like what your neighbors mow? If so, then no, not dead … just dormant, which is sort of like a bear hibernating. By flowers, you likely mean the ones that bloom for weeks or even months at a time: pansies, zinnias, etc. Brightly colored, long bloom time. These are the annuals mentioned above: they live a year or less. Those ARE dead each winter. They come back by re-seeding (or by your gardener buying more at the big box store) to start the life cycle from scratch. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [April 26, 2021, 7:44am UTC](https://boards.straightdope.com/t/what-causes-the-flowers-to-come-back-every-spring/940764/13 "2021-04-26T07:44:58Z")
> [@purplehorseshoe](#): > > By “grass” you mean a turf lawn, like what your neighbors mow? If so, then no, not dead … just dormant, which is sort of like a bear hibernating. Or like a deciduous tree that has dropped its leaves. The tree is alive; the leaves are disposable and will be regrown. ---
**Author:** ![am77494](https://avatars.discourse-cdn.com/v4/letter/a/d2c977/32.png) [@am77494](https://boards.straightdope.com/u/am77494)\ **Post date:** [April 26, 2021, 8:08am UTC](https://boards.straightdope.com/t/what-causes-the-flowers-to-come-back-every-spring/940764/14 "2021-04-26T08:08:12Z")
> [@purplehorseshoe](#): > > Those ARE dead each winter. > They come back by re-seeding (… I live in Houston, TX suburbs. Our growing zone is 9A. Depending on the severity of the winter, many so called annuals behave like perennials. Plants like petunias don’t die back but remain and grow back stronger in spring. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [April 26, 2021, 8:16am UTC](https://boards.straightdope.com/t/what-causes-the-flowers-to-come-back-every-spring/940764/15 "2021-04-26T08:16:34Z")
Yeah, there’s a blurred line between annual and perennial - many plants that are technically perennials can still flourish as annuals outside of their preferred climate conditions. Tomatoes and capsicums, for example (interestingly, also in the same family as petunias - Solanaceae seems to like this trick) ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [April 26, 2021, 12:38pm UTC](https://boards.straightdope.com/t/what-causes-the-flowers-to-come-back-every-spring/940764/16 "2021-04-26T12:38:09Z")
I suppose another way to look at @am77494 and @Mangetout’s observations just above is that in the wild, plants will “migrate” (spread new individuals actually) from their current best habitat poleward until they find themselves dying off each year from the cold and short growing season. If they have a robust enough reproduction system that can create new reproducing adults in a single growing season they _may_ become _de facto_ annuals in that marginal habitat. And if they can’t quite manage that trick they simply aren’t found that far poleward. Humans of course can plant anything anywhere for reasons both smart and dumb. And force it to grow or replace it when it just won’t / can’t. ---
**Author:** ![am77494](https://avatars.discourse-cdn.com/v4/letter/a/d2c977/32.png) [@am77494](https://boards.straightdope.com/u/am77494)\ **Post date:** [April 26, 2021, 1:17pm UTC](https://boards.straightdope.com/t/what-causes-the-flowers-to-come-back-every-spring/940764/17 "2021-04-26T13:17:06Z")
> [@LSLGuy](#): > > If they have a robust enough reproduction system that can create new reproducing adults in a single growing season they _may_ become _de facto_ annuals in that marginal habitat. And if they can’t quite manage that trick they simply aren’t found that far poleward. Agree LSLGuy. This February, we had a 100+ year freeze event. Many of my annuals and perennials are dead from the freeze, but some are coming back from the freeze. The reason, I am bringing this up is that poleward migration of plants depends not only on the yearly weather but also the long term freak weather events > [@LSLGuy](#): > > And force it to grow or replace it when it just won’t / can’t. People try growing plants like peonies, lilac, cherries, etc - some may grow briefly but they don’t flower/fruit. Again this is in the Houston weather. ---
**Author:** ![Jackmannii](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jackmannii/32/311_2.png) [@Jackmannii](https://boards.straightdope.com/u/Jackmannii)\ **Post date:** [April 26, 2021, 1:35pm UTC](https://boards.straightdope.com/t/what-causes-the-flowers-to-come-back-every-spring/940764/18 "2021-04-26T13:35:32Z")
> [@Mangetout](#): > > Yeah, there’s a blurred line between annual and perennial - many plants that are technically perennials can still flourish as annuals outside of their preferred climate conditions. Another example of a plant commonly sold and referred to as an annual is Nicotiana alata - flowering tobacco. I was surprised this spring to see a couple of my plants regenerating from the roots in zone 6b after a minimum winter low of 9F, as I’d always thought it was a true annual. Nope. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [April 26, 2021, 2:58pm UTC](https://boards.straightdope.com/t/what-causes-the-flowers-to-come-back-every-spring/940764/19 "2021-04-26T14:58:43Z")
Again - Nicotiana is in the Solanaceae - seems to be pretty much the party trick of that family to be perennial, but also reproduce in the first season, so as to function as an annual where required. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [April 26, 2021, 3:02pm UTC](https://boards.straightdope.com/t/what-causes-the-flowers-to-come-back-every-spring/940764/20 "2021-04-26T15:02:31Z")
> [@am77494](#): > > Agree LSLGuy. This February, we had a 100+ year freeze event. Many of my annuals and perennials are dead from the freeze, but some are coming back from the freeze. The reason, I am bringing this up is that poleward migration of plants depends not only on the yearly weather but also the long term freak weather events Yep, elevation is another thing - some of the plants we have been discussing are indigenous to places like Peru, where there are colder/warmer/wetter/drier microclimates due to elevation, exposure, etc. Another thing that perennials-as-annuals can do is to reproduce quickly in a wet spring season, then if the summer gets really dry, survive as seeds, or if it’s not so dry, survive also as perennials [Next page](https://boards.straightdope.com/t/what-causes-the-flowers-to-come-back-every-spring/940764.md?page=2)