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Calibrachoa Secret Revealed


I thought calibrachoa was a tender perennial. That’s what it said on the label: hardy to zone 9, a zone-ruling I’ve tried to believe I could actually get away with in my area, if I protected the plant. Yet unless we have unusually warm winters, a zone-9 classification usually means the kiss of death.

I bought calibrachoa at my local drugstore, one of my sources for those cheap common annuals I pretend to despise but actually find pretty handy for tucking in between perennials when they are drooping, flagging, dormant, or nonflowering. Calibrachoa is a newly-fashionable plant, generous in its flowering, good in containers.

It’s no accident that it looks like a minature petunia; the two are closely related, and calibrachoa was once in the same genus. (Some people argue that it still should be. Lumpers vs. Splitters, round 873.)  Like petunias, calibrachoas are from South America, but they took more time to get into gardens outside their home country. Suntory, the Japanese breeding program that has come up with heat-tolerant fuchsias, started working with calibrachoas in the late 1980s. Their work has obviously come to fruit (or flourish), since you can now find plentiful-flowering calibrachoas in every nursery and drugstore.

So I tried calibrachoa last year, thinking of it as an annual, and I was pretty pleased with the combination in this pot (photo at the top of the post):  the dull purple of purple sage (not the Zane Grey kind, the culinary kind: Salvia officinalis ‘Purperascens’) sparked up by small, pink-orange trumpets of Calibrachoa calimor ‘Desert Shine’. I didn’t expect it to be more than a seasonal show.

But hark. I was repotting some perennials which badly needed it (we can often get away with doing this in January in our climate; January is bare-root-planting time here, and we generally get a warm spell that makes it fairly pleasant to do) – I was repotting perennials when I saw something that shouldn’t have been there: green calibrachoa leaves, peeking out of the sage pot.

Since we’ve had a winter ranging into the mid-teens F (in the neighborhood of -8 C), cold for us, we have definitely dropped below zone-9 minimums. The University of Illinois website, where I got some of my calibrachoa information, says they are hardy to “zones 8 or 9”, which may be good enough if you live in Illinois, but is entirely annoying if you live in more-or-less zone 8. In the hills, no zone is sure. I’ve had to drain the water pipes several times this year, usually a sign that every borderline plant I have (brugmansias spring to mind) will be deader than a doornail.


So: is calibrachoa actually hardier than advertised? That would make a refreshing change. Or (my secret hope) do I have some hardy calibrachoa sport, some maverick that will change the world of calibrachoas as we know it?

It’s dangerous to draw conclusions. I’ll just keep my eye on that calibrachoa and see what happens.

{ 15 comments… add one }

  • kerri February 22, 2009, 3:00 pm

    I’ve been enjoying calibrachoas in containers and window boxes for the past several years, and love their continuous, abundant blooms.
    I managed to overwinter one last year, but it never really amounted to much during the growing season. I’m trying again this winter with several. They did well for a while (in the cellar under lights), but none of them look like they’ll make it at this point.
    Your cali looks pretty combined with the dark sage.

  • Daffodil Planter February 22, 2009, 3:31 pm

    I was reading along thinking, “That Pomona is such a brainiac; I’ve never heard of this plant and it puts me in mind of a petunia” when you announced that it was indeed related. Whew. I can live to blog another day. Lovely combo in the pot, with the purple sage that is neither Zane Grey nor New Riders of. Fingers crossed that you have a marvelous hardy specimen there!

  • catmint February 23, 2009, 7:00 am

    hmm, don’t usually go for petunias or its relis, but must admit they look pretty nice associating with the purple sage in the photo.

  • Pomona Belvedere February 24, 2009, 1:48 pm

    Kerri, interesting to hear a report of other hardy(ish) calibrachoas. And a useful warning for me: it looks as if I may have to give mine some special attention if I want it to bloom again next year. Many nursery-grown plants are force-fed to bloom the one year, but as with so many quick fixes, they pay extra for it in ensuing years.

    DP, you will feel even better when you hear that it wasn’t until researching for this post that I realized and petunias were related. ‘Brainiac’: I’ll have to remember that next time I can’t find my keys or forget to pay my bills on time.

    Catmint, I’m not usually a petunia fan either (though I have enjoyed one of the fragrant species types), I might not have opted for calibrachoas had I but known (see above).

  • Jonathan Justice November 29, 2009, 10:13 pm

    Petunias and Calibrachoas are shrubs from places that do get a bit of frost, so they can do some recovery things we do not expect from Annuals. A couple of years ago, I actually had a hanging pot full of Wave Petunias freeze solid in temperatures down around 20, at the end of October. I hung it up in the Greenhouse because the foliage had not failed. Shoot growth was stopped, but two months later it was blooming on new shoots. It was a huge show in March and April. Zone 5 here means I do have to bring them in if I want to carry them over, but I would think that your Zone 8 climate would allow you to store them dry in a shed or a garage , or even under a tarp for a couple of months, and start them back up with a good soak when you see milder conditions.

  • Pomona Belvedere November 29, 2009, 10:39 pm

    Jonathan, thanks for that tip. I do have a species petunia (P. integrifolia, I think) which seems to carry through our winters here, but never had any luck with others. This seems like a simple way to get blooms lots earlier, thanks for the tip. Must have been a fun discovery; don’t you love playing science in the garden?

  • Janet May 17, 2010, 1:55 pm

    I tried calibracoa as a bedding plant with nearly all day sun and ample water from a sprinkler system, but it did not bloom…any ideas why?

  • Pomona Belvedere May 18, 2010, 8:14 am

    The only things I can think of is that perhaps the soil was too rich in nitrogen (make leaves grow) and it didn’t have enough phosphorus and other minerals that make things flower. Or there was some problem with pH. Otherwise, honestly, conditions sound ideal.

  • Stephanie April 5, 2015, 10:33 pm

    My annual calibrachoa got dried out when I was out of town working, & my husband did not water it . that was in October . I thought it just died so I kept it just in case I needed the pot. Well I decided to water it again & see what it would do. Does anyone think that it will grow back and here it is April? I live in south Carolina so I dunno if it will grow back since it dried out 6 months ago?

  • BAMBI PH. June 27, 2015, 3:36 pm

    My sweet daughter got me a potted hanging “Calibrachoa” for Mothers Day 2015. It was a beautiful purple but here it is 1 1/2 months later and it is already wilted and turned a yellowish brown color, of course the flowers fell off first. I bought that liquid foaming plant food from home dept, and used it twice as directed. I have it hanging on the corner of the house where it gets approx. 4-5 hrs. of sun a day. it is only June and I can’t for the life of me figure out “WHY” it’s dying?!? Please help….

  • Evgeny October 24, 2015, 12:37 pm

    What a nice splash of color your putenias provide! I have a tiny bit of gaura still blooming that hid from the frost. I love those little whirling butterflies. Happy GBBD to you!

  • Ms.girl March 31, 2016, 1:02 pm

    Bought a hanging basket at WalMart last year with the calli and a blue flower. I left it out just behind the garage -, not protected, and the calli is blooming like crazy. Had to go to a nursery to find out what it was. I want some more!

  • Calibrachoa January 5, 2017, 7:05 pm

    I had lemon slice this year and it bloomed through a few light frost.

  • Kristen Osborne May 11, 2017, 2:31 pm

    I left town on a Saturday (watered it before I left) and came back on Monday afternoon. It had completely wilted. Completely! I immediately watered it and it quickly started to show signs of life. It’s now Thursday and it still hasn’t returned to its former vibrancy. I’m new at this so I’m wondering if it’s ok to dead head the lifeless blooms. They stick out like a sore thumb. Makes me a little sad because the pot was overflowing with bright yellow blooms and greenery before I left town.

  • IMBabci2 November 26, 2017, 4:32 am

    Surprisingly, I have 4 window boxes of Calibrachoa Dreamsicle which have thrived (greenery only) thru 3 nights of 27 degrees and heavy frost. I will move them to the lean-to greenhouse when the temps go under 26… cut them back in the spring and hopefully they will rebloom?

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