Why Isn’t My Moonflower Blooming?

Aug 28, 2017 | Gardens

Like many others, I plant moonflower (Ipomoea alba) in the early summer to fill a small trellis with a quickly growing annual vine. I anticipate the large, round and fragrant flowers, but most of the summer goes by without any sign of a bloom. I’m not alone. I know from calls to the radio station and emails to Plantrama that people wonder why some of their plants take so long to flower.

In fact, my moonflower, and several other plants, are simply showing signs of photoperiodism. Ellen and I discussed this in an episode of Plantrama recently. Basically, photoperiodism is an organism’s response to the hours of daylight. Or, as in this case, the hours of darkness. Because my moonflower doesn’t come into bloom until the hours of daylight decrease and the hours of darkness increase.

Here we are at the very end of August and my moonflower vine has yet to bloom. Typical.

The good news? When I look closely I see these buds. Now that the days are getting shorter and the nights longer, my moonflower will soon come into bloom.

Soon I know that I’ll be treated to these large, slightly fragrant flowers.

21 Comments

  1. Nanette Ingraham

    such beauty C.L…. sigh…. ♥ Nan

    Reply
  2. robert jackson

    Always have success with morning glories but no blossoms this year. Any connection?

    Reply
    • CL Fornari

      Yes – although morning glories tend to not only be triggered into flowering by longer nights, but by stress. So if it’s too moist or fertile they will produce lots of leaves and no flowers. We can’t control the rain but in future keep morning glories on the lean side in terms of soil and water.

      Reply
    • Mary Long

      We have had multiple rainy days and sparse sun for most of June and now July. I’ve had 2-3 blooms on my Moon Flower vine with many large, healthy leaves! I’m wondering if the lack of sunshine is affecting the blooming?

      Reply
    • Christina Shannon

      I have many flowers but they do not open. In the morning they are still tight. Then the flower falls off with out opening.

      Reply
      • CL Fornari

        Christina – have you gone out around 11 at night to look at this vine with a flashlight? Sometimes they open in the dark, and are closed again in the morning. Each flower only lasts one night. Check and let me know!

        Reply
  3. Judith pearsall

    Is this the right place to ask if there are any tips you have C L about drying hydrangeas to stay beautiful all winter? My hydrangeas are a beautiful hue now and it would be fun to preserve them.

    Reply
    • CL Fornari

      There are several ways to dry hydrangeas. The mopheads (blue, purple, pink) can just be cut and put in a vase without water. They dry beautifully as they are. Some people cut them and hang upside down but this isn’t necessary. Take all leaves off. The white ones (paniculata group) sometimes dry well by either hanging upside down or using silica that you buy in craft stores. But they turn brown fairly quickly. To keep the colors of the blue ones, keep the dried flowers out of direct sun and away from bright windows.

      Reply
      • Vicki Grochowski

        I had huge, beautiful buds on my bush, but they would not open!!!! Could the bright LED bulbs in the two streetlights that light my property be the problem?

        Reply
        • CL Fornari

          Vicki,
          It could be that the lights are the problem – but are you sure you’re growing moonflower VINE?

          Reply
  4. Janet Greenwood

    My moonflower vine keeps growing but no sign of flowers. What am I doing wrong? Is there something I an do to encourage flowers to bloom?

    Reply
    • CL Fornari

      They need decreasing hours of daylight to stimulate bloom. The thing you have to do is to wait patiently for the days to get shorter.

      Reply
  5. Don Straub

    Earlier blooming seems to be encouraged by planting on the east or west side of structures, dense trees, and anything else that blocks sunlight and street lighting for a few hours.

    Reply
  6. Cindy Purdy

    My moon flower vines are quite healthy but still no blooms. Saw your advice about shorter days so will be patient.
    Seems like a long time ago I grew moon flowers that weren’t vines. Are these still available?

    Reply
    • CL Fornari

      Cindy,
      Many plants have the same or similar common names so it’s possible that you grew something that someone called “moonflower” that wasn’t a vine. But the only plant with that name that I know is the vine. I hope yours blooms soon!

      Reply
  7. Kathy Betche

    There is a wild plant called Moonflower, it is more of a shrub. I have both kinds and they have very sparse flowers this summer.

    Reply
  8. Dee Dee Harrington

    Gee, I well know this problem. In zone 7A the vines were scampering everywhere–but no flower. So I rerouted the end of the vine aiming back on itself (sort of in the direction of the root). I figured that if the vine is confused I am even more so. Anyway this was a good move, the vine is covered in flowers and I’m happy. We all waited too long for this. Try it. I fertilized every 2 weeks.

    Reply
    • Dawn F

      I have had lots of trouble with my hydrangeas They looked dead so cut them both back They were new plants and had a small bloom on them and I have brought them back this year The plants are looking healthy but no blooms I planted them in pot so I could keep an eye on them because something ate them out in the yard bed Any advice on how to grow these?

      Reply
  9. Carol Hughes

    Dee Dee Harrington,, Could you explain what you meant, please?

    Reply

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