Plants are amazing in their complexity and habit. There is an intriguing collection of plants that close up at night – a phenomenon called nyctinasty. Nyctinasty is thought to protect pollen and nectar or to protect the plant from cool, chilling temperatures. Sometimes this tendency confuses people into thinking that something is wrong when they close up during the day under low light conditions. Here is a list of these little tricksters so you can be on the lookout for them:
- California Poppies – simple 4 petaled flower that closes up in low light
- Gazanias – pollinated by butterflies during the day, fold up in low light
- Hibiscus – blossoms open for just 1 day and then close at night; usually do not reopen
- Morning Glory – bloom in the early morning, close at night, blossom lasts 1 day
- Osteospermum – also known as African Daisies
- Oxalis – also known as a purple shamrock with delicate white flowers, foliage folds upward
- Portulaca – also known as Rock Roses, a native of South America butterfly attractor
- Talinum – whimsical pink flowers on spires atop chartreuse foliage that folds upwards at night
- Sanguinaria – white daisy-esque flowers with yellow eyes
- Crocus – close on cloudy and rainy days
- Tulips – close on cloudy and rainy days
- 13 Flowers that Bloom at Night
- 1. Evening Primrose
- 2. Moonflower
- 3. Datura
- 4. Brugmansia
- 5. Night Gladiolus
- 6. Night Phlox
- 7. Night-Blooming Jasmine
- 8. Night-Scented Orchid
- 9. Nicotiana
- 10. Four O’Clock
- 11. Casa Blanca Lily
- 12. Evening Stock
- 13. Tuberose
- What Is Nyctinasty – Learn About Flowers That Open And Close
- Nyctinastic Plant Info
- Types of Nyctinastic Plants
- Welcome the Plants That Move on their Own
- 10. Orchidaceae
- 9. Witch Hazel
- 8. Sandbox Tree
- 7. Triggerplant
- 6. Sensitive Partridge Pea
- Here’s How Flowers Move—and Why
- Thank you!
- Types of Flowers That Open With the Sun
- Gazania Daisy
- Morning Glory
- California Poppy
- Do all flowers close up at night?
- Why do some flowers close at night?
- It is most likely to protect the pollen.
- Flowers that close at night include poppies, tulips, crocus, and hibiscus.
- How plants open and close their flowers
13 Flowers that Bloom at Night
We all want gardens that are full of color, texture and visual interest during the day, but have you thought about what your garden looks like at night?
Many flowers close when the sun goes down or the temperature drops, which could mean that your outdoor living areas lose some of their visual appeal at night. This may not be a concern for you, but if you enjoy spending time on your patio late in the day or often entertain in the evening, this is something you should consider.
Night blooming flowers can reflect the moonlight, add color for your guests to enjoy and are often much more fragrant than their day-blooming counterparts. One of the reasons flowers that bloom at night are often more aromatic is that they need to attract nocturnal pollinators that must find them in the dark. This is also why most night bloomers have white flowers that reflect light and are more visible at night.
By planting at least a few night blooming plants in your garden, you can enjoy your garden just as much at night as you do during the day. Breathe in the fragrance, watch butterflies and hummingbirds late into the evening, and enjoy splashes of color through the night.
To get you started, here are 13 flowers that bloom at night.
1. Evening Primrose
Evening primrose (Oenothera biennis) is a biennial plant native to parts of North America. The blooms open quickly, which means you can sit on your patio in the evening and enjoy the show as the yellow flowers open before your eyes. They will then stay open until about noon the following day. Many parts of the plant are edible, and this is the source of evening primrose oil, which is used to treat eczema, premenstrual syndrome, multiple sclerosis, and rheumatoid arthritis.
Evening primrose typically blooms from late spring to late summer and attracts pollinators, including bees, moths, and butterflies.
Moonflowers (Ipomoea alba) have large, white or pink flowers (usually white) that open quickly in the evening and stay open until after sunrise. On cloudy days, they sometimes stay open later into the afternoon, but usually close in the morning once the sunlight reaches them. This perennial, evergreen vine grows quickly, prefers moist soil and requires at least partial sun, but prefers full sun.
Parts of this plant are edible, so it is very important that you differentiate between this moonflower and the next plant on the list, Datura, which is also sometimes referred to as moonflower and is highly poisonous.
Datura is sometimes called moonflower but more commonly referred to as devil’s trumpet. With large, showy, trumpet-shaped blossoms, these night blooming flowers in shades of pink, purple, yellow, or white are a beautiful addition to a night garden. However, a mentioned above, Daturas are highly poisonous, so they should be planted with caution and never in areas where children or pets spend time. Datura is so poisonous that some cultures have historically used it as poison.
Datura plants are usually grown as annuals and can grow to about six feet tall. They are often confused with Brugmansia (aka angel’s trumpets), but while devil’s trumpets and angel’s trumpets are closely related, they are separate genera.
Angel’s trumpets (Brugmansia) are believed to be extinct in the wild but are commonly seen in gardens and can easily be found at garden centers. Angel’s trumpets and devil’s trumpets are often confused, but it easy to tell them apart. Angel’s trumpet is more or a bush or shrub and can even be grown as a tree, while devil’s trumpet is a leafy plant. Another easy-to-identify difference is that the large, peach, white, green, red, orange, or pink, trumpet-shaped flowers of the angel’s trumpet hang down towards the ground, while the blooms on a devil’s trumpet are erect, facing the sky.
These night blooming flowers are easy to grow in Coastal California and in inland areas that are in gardening zones 8 or 9, but, like Datura, angel’s trumpets are highly poisonous and should not be planted where children or pets spend time. The fragrance is lovely and will enhance your experience as you enjoy your night garden; just make sure they are out of reach if little ones or pets share your outdoor living areas.
5. Night Gladiolus
Night gladiolus (Gladiolus tristis) generally blooms in late spring to mid-summer and can grow to about four feet in height. It is a good grower in coastal and near-coastal California, but it is not drought tolerant and requires regular irrigation. They prefer full sun and well-draining soil, so be sure to mix in compost before planting corms if you are working with the clay soil so common in Southern California.
If you want to enjoy these light-yellow flowers that bloom at night and the spicy fragrance they release, be sure to plant them somewhere visible but out of reach for pets and children, since this is another poisonous plant that needs to be kept away from little hands.
6. Night Phlox
Night phlox (Zaluzianskya capensis) is also called midnight candy, which is more than just a fun name: It is a nod to the sweet fragrance released by this night blooming flower. Perfect in an evening fragrance garden or a moon garden, night phlox brings both fragrance and color in shades of pink, white and purple. There are even some that are a reddish-maroon hue. Night phlox is an annual that grows well in containers or flowerbeds and attracts butterflies, bees and birds to your garden.
Night phlox grows best in full sun or partial shade and is pretty drought-tolerant once established. The honey-almond-vanilla fragrance is a delightful addition to a night garden, particularly for summer and fall entertaining, when they are usually in full bloom.
7. Night-Blooming Jasmine
Night-blooming jasmine (Cestrum nocturnum) is a member of the Solanaceae family, which means it is actually a nightshade and is not the jasmine most folks have in their gardens. This night blooming flower has white blossoms with hints of green and has a strong fragrance that is also most present at night. As an evergreen shrub, night-blooming jasmine adds visual interest to your night garden throughout the year. It is a good grower and is even considered a weed in some parts of the world.
The lovely fragrance makes this a good choice for growing near outdoor living areas, but keep in mind that all members of the Solanaceae family have some level of toxicity, and the strong scent is known to be an irritant for some folks with respiratory issues, such as asthma.
8. Night-Scented Orchid
You cannot always rely on night-scented orchid (Epidendrum nocturnum) to open its blooms at night, but you can rely on the fragrance those blooms release after the sun goes down. This swamp-loving flower is found in parts of Central America, South America, the West Indies, and Mexico and is most often found in Florida in the United States, but it can be grown elsewhere if you are diligent about watering and maintaining your plants.
Since these orchids do not require pollinators for propagation, the white and yellow flowers sometimes open infrequently or not at all.
Nicotiana is a genus of plants that includes tobacco plants used for making cigars and cigarettes, but the variety that is smoked is usually not counted among the choices available at your local garden center. This night blooming plant can be transplanted from nursery plants, which is the fastest way to add color to your flowerbed, but it germinates quickly, so you might also try growing this one from seed.
The flowers that bloom at night usually come in shades of white, pink, green, or red and have a strong fragrance that attracts night pollinators to your yard. If you plant them near your patio, you may be able to enjoy the flowers and the hummingbirds they attract when they open in the late afternoon or early evening.
This is another member of the Solanaceae family, so – as with all nightshades – use caution when choosing a spot to plant this one.
10. Four O’Clock
Four o’clock (Mirabilis jalapa) flowers have some unique qualities when compared to other night blooming plants. A single four o’clock plant can produce more than one color of flower and a single flower will sometimes have more than one color. The colors most often found on four o’clocks are white, yellow, pink, red, or a stunning magenta, which makes them an easy choice for adding color to moon gardens.
Four o’clocks are often grown as annuals, but they can be grown as perennials in Coastal California. If you live in an area with cooler winters, they will die back with the first frost, but they will return in spring.
11. Casa Blanca Lily
Casa Blanca lilies (Lilium ‘Casa Blanca’) are fragrant, beautiful additions to a moon garden where their large, white flowers that bloom at night will reflect the moonlight. This is also a good addition to a cutting garden, just make sure to leave plenty of stem and leaves on the plant to ensure the bulb gets the energy it needs to overwinter in your garden and come back in the spring.
When planting these gorgeous flowers, keep in mind that all lilies are toxic to cats and dogs.
12. Evening Stock
Evening stock (Matthiola longipetala), also known as night-scented stock, is a hardy annual that can be grown just about anywhere in North America. While the purple and white flowers can look a little wilted during the day, the petals spread and come to life at night. This is also when evening stock is at its most fragrant, so be sure to plant it near your outdoor living areas if you often entertain in the evening.
Tuberose (Polianthes tuberosa) is perhaps best known for its inclusion in perfumes, which makes it a good choice if you are looking for a night blooming flower with a strong, inviting fragrance. This perennial plant is easy to grow from bulbs, prefers full sun and warmer climates, and produces clusters of white flowers on a long spike in mid- to late-summer. The white flowers will reflect the moonlight in your night garden, or you can use this one as a cutting flower for bouquets or floral arrangements.
You can grow tuberose in flowerbeds and borders, but it will also do just fine in large flowerpots, which might let you get this aromatic choice even closer to your outdoor entertaining areas.
What Is Nyctinasty – Learn About Flowers That Open And Close
What is nyctinasty? It’s a valid question and a word you definitely don’t hear every day, even if you are an avid gardener. It refers to a type of plant movement, like when flowers open in the day and close at night, or vice versa.
Nyctinastic Plant Info
Tropism is a term that refers to plant movement in response to a growth stimulus, like when sunflowers turn to face the sun. Nyctinasty is a different type of plant movement that is related to night and day. It is not related to a stimulus, but is rather directed by the plant itself in a diurnal cycle.
Most legumes, as an example, are nyctinastic, as they close their leaves up each evening and open them again in the morning. Flowers may also open in the morning after closing for the night. In some cases, flowers close during the day, and open at night. A subtype of nyctinasty is familiar to anyone who has grown a sensitive plant. The leaves close when you touch them. This movement in response to touch or vibration is known as seismonasty.
Why plants that move in this way is not fully understood. The mechanism of the movement comes from changes in pressure and turgor in the cells of the pulvinis. The pulvinis is the fleshy point at which the leaf attaches to the stem.
Types of Nyctinastic Plants
There are many examples of plants that are nyctinastic. Legumes are nyctinastic, closing up leaves at night, and include:
Other examples of nyctinastic plants include flowers that open and close include:
- California poppy
- Morning glory
Some other plants you can put in your garden that will move from day to night and back again include silk tree, wood sorrel, prayer plant, and desmodium. It may be tough to actually see the movement happening, but with nyctonastic plants in your garden or indoor containers, you can observe one of the mysteries of nature as you watch leaves and flowers move and change position.
Welcome the Plants That Move on their Own
By Joe Dysart
May 16, 2019
Researchers are creating cybernetic life-forms that incorporate plants with robotics, which could be used for a variety of applications.
Credit: Sun Tianqi
Robotics entrepreneurs are designing interfaces that enable everyday houseplants to move on wheels, amble on robotic crab legs, and more.
Researchers at the Massachusetts Institute of Technology (MIT), for example, have designed an interface that enables a houseplant atop computerized wheels to command those wheels to move it towards light. The result is a startling display in which the wheeled houseplant moves towards a light in a few seconds, rather than over the course of a few days, when that light is switched on.
The researchers created the ‘cybernetic life-form’ by attaching electrodes to the plant to monitor its chemical reactions and enable it to signal to the computerized wheels to move when it detects light.
“The agency of such movements rests with the plant,” says Harpreet Sareen, an assistant professor at the Parsons School of Design who developed the experiment with MIT professor Pattie Maes.
Similar research is under way by Sun Tianqui, founder of Beijing-based robotics company Vincross who engineered a plant atop six robotic legs that crawls towards a light source (and crawls away from the light when it has had its fill).
Tianqui says he developed motions for the crab-like plant robot using Vincross’ MIND SDK. “In fact, for many of the motions, I only need to call the motion library of the MIND SDK, so it is very simple to develop,” Tianqui says. He also used a distance sensor, accelerometer, soil moisture sensor, and 720p camera.
“Originally, I did not plan to commercialize,” Tianqui says, “but based on the interest I’m hearing, I see that people are interested in adding robotics into their homes with a product such as this. So maybe we better get building.”
Yet another research project in the same space is flora robotica, which is based by the European Union’s Horizon 2020 research and innovation program, and is coordinated by Heiko Hamman, a professor of service robotics at Germany’s University of Luebeck. That ongoing experiment uses a combination of sensors and computers to grow plants into shapes dreamed up by the researchers. The purpose of the project is to investigate symbiotic relationships between robots and plants, “and to explore the potentials of a plant-robot society able to produce architectural artifacts and living spaces,” according to the project website.
Hamman says the team uses an everyday Raspberry Pi single-board computer programmed with Python to pull-off its plant/machine collaboration. “In addition, we use a number of state-of-the-art machine learning tools, such as LSTM networks and neuroevolution to automatically generate data-driven holistic plant models and robot controllers.”
With MIT’s ‘houseplant-on-wheels,’ Sareen says one of the greatest challenges was to translate the plant’s bioelectric reaction to light, given that the reaction only generates an electric signal of a few millivolts. The solution: “We use two levels of operational amplifiers and instrumental amplifiers to make these signals detectable, along with hardware signal filtering to isolate electrical spikes.
“We also isolate the plant for a day, not varying anything in terms of external environment, and then only change the light. This isolation helps us get a single signal which can be co-related to change of light.”
Sareen and Maes are now looking into developing a commercial kit based on their research, which scientists and others could use to manipulate plant electrochemical reactions. In the longer term, they’d like to develop a variety of commercial kits that would capture and manipulate a full spectrum of electrochemical signals naturally generated by plant and animal life.
“It is a piece of thought-provoking work,” says Ping Ma, an assistant professor of statistics at the University of Georgia, of Sareen and Maes’ work. “The research manifests a perfect merger of natural intelligence” and machine technology.
Manoj Karkee, an associate professor in the Biological Systems Engineering Department of the Center for Precision and Automated Agricultural Systems at Washington State University, agrees: “This work is intuitive and unique, something that has a huge potential for commercial adoption.”
Computer scientists and others working in the space anticipate attempts to combine plant life with machines in many different applications.
Washington State’s Karkee, for example, envisions scientists leveraging plant robotics for practical purposes, such as employing robots to sense when new branches emerge on fruit trees.
Meanwhile, the University of Luebeck’s Hamman says his team is looking into practical ways to commercialize flora robotica, such as harnessing the technology to grow plants on the walls of buildings, and away from doorways and windows. “Another idea could be to target for the consumer market with a device that grows plants in your living room without you having to care for it. You could even define the direction to which it should grow or not grow.”
“We will see robotics fused with many different subparts of science to facilitate our daily lives and help build a sustainable community,” says Laura Blumenschein, a Ph.D. candidate with the Collaborative Haptics and Robotics in Medicine (CHARM) Lab at Stanford University, agrees: “I think that before long, we will have robots that can grow useful structures on demand or that can ‘live’ with plants in order to monitor soil condition, weather, and other phenomena over long stretches of time.”
Adds Kasper Stoy, a robotics and embodied artificial intelligence researcher serving as associate professor in the Software and Systems Section of the IT University of Copenhagen, “I think it would be interesting to see technology forming a symbiotic relationship with each other to extend the lifetime of both and the usefulness of both.”
Josh Bongard, an associate professor in the College of Engineering and Mathematical Sciences of the University of Vermont, sees the ultimate rendering of plant with machine incorporating many of the most invigorating advances in computer science of late. “Whatever the ‘killer app’ in five years’ time will be, it will probably be some combination of the cloud, brain-computer interaction, and robots fused with organic material,” Bongard says.
“Life grows exceedingly complex, yet robust forms from simple seeds, or eggs, while machines can do certain tasks very, very quickly and accurately,” he adds. “Discovering how to combine these two systems to create hybrid systems that are better than either alone is a daunting yet exciting prospect.”
Equally hopeful about plant robotics R&D is University of Luebeck’s Hamman, although he is more conservative on how quickly the tech will develop. “In a short period of five years, I wouldn’t expect too much change,” Hamman says. “We are still at the beginning; we have just created the basic methodology.”
Still, says University of Vermont’s Bongard, “It’s only a few short steps from plants and robots to deep philosophical questions about the nature of thought.”
Joe Dysart is an Internet speaker and business consultant based in Manhattan, NY, USA.
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Yes we can brood over the old definition where plants were described to be non-motile in comparison with animals, which is now null and is a thing of past. Unlike what we were told at our kindergartens, not only plants possess various movements like kinesis, tropism, taxis and nastic movements which are too slow for us to observe but some do possess rapid movements that surprise us and make us touch them time and over again. Here is a collection of 10 most beautiful plants with such rapid kinetic activities.
Orchidaceae, commonly referred to as the Orchid family, is a morphologically diverse and widespread family containing a number of beautiful dazzling flowering plants that possess rapid movement due to their strong highly specialized pollination behavior associated to them. Orchids generally have simple leaves with parallel veins but are well known for the many structural variations in their flowers. In orchids that produce pollinia, pollination happens as some variant of the following. When the pollinator enters into the flower, there are a series of contractions and relaxations as that of a muscle occurs with the flower seen by naked eye and similar activity occurs when the pollinator enters another flower thus pollinating it. The possessors of orchids may be able to reproduce the process with a pencil, small paintbrush, or other similar device.
9. Witch Hazel
Witch-hazel (Hamamelis) are deciduous shrubs or (rarely) small trees growing to 3–8 m tall, rarely to 12 m tall. They are popular ornamental plants, grown for their clusters of rich yellow to orange-red flowers which begin to expand in the autumn as or slightly before the leaves fall, and continue throughout the winter. The horticultural name means “together with fruit”; its fruit, flowers, and next year’s leaf buds all appear on the branch simultaneously, a rarity among trees.H. virginiana flowers in the fall of the year. The flowers of the other species are produced on the leafless stems in winter, thus one alternative name for the plant, “Winterbloom”.Each flower has four slender strap-shaped petals 1–2 cm long, pale to dark yellow, orange, or red. The fruit is a two-part capsule 1 cm long, containing a single 5 mm glossy black seed in each of the two parts; the capsule splits explosively at maturity in the autumn about 8 months after flowering, ejecting the seeds with sufficient force to fly for distances of up to 10 m, thus another alternative name “Snapping Hazel”
8. Sandbox Tree
The Sandbox tree, also known as Possumwood and Jabillo, is an evergreen tree that can grow to 30 m. It is recognized by the many dark, pointed spines and smooth brown bark. These spines have caused it to be called Monkey no-climb. The red flowers have no petals. Male flowers grow on long spikes; female flowers are solitary in axils. The fruit is a large capsule with explosive dehiscence. When ripe, pods catapult the seeds as far as 100 meters (300 ft). It has also been known as the Dynamite tree, so named for the explosive sound of the ripe fruit as it splits into segments.
Stylidium< (also known as triggerplants is a genus of plants that derive its name from Stylos, which refers to the distinctive reproductive structure that its flowers possess like a column or a pillar. Pollination is achieved through the use of the sensitive “trigger”, which comprises the male and female reproductive organs fused into a floral column that snaps forward quickly in response to touch, harmlessly covering the insect in pollen. They have beautiful flowers, and although species of the genus represent a very diverse selection of plants but most easily identified by their unique floral column, in which the stamen and style are fused. The column—also commonly called a “trigger” in this genus—typically resides beneath the plane of the flower.
6. Sensitive Partridge Pea
Healthy Home Gardening
Chamaecrista nictitans (Sensitive Partridge Pea, Small Partridge Pea or Wild Sensitive Plant) is a herbaceous species of legume widely distributed through the temperate and tropical Americas. It is an annual plant capable of rapid plant movement—its leaflets fold together when touched.
Here’s How Flowers Move—and Why
It may not surprise you that sunflowers have something of a thing for the sun. OK, that’s true of all plants, which is why they orient their flowers and leaves to follow the sun as it moves across the sky. But it’s sunflowers that are the most obvious about it, craning their big yellow heads atop their long green stalks toward the east in the morning and due west by sundown. Even at night they’re hankering for the light, turning their faces back east in the dark so they’ll be ready to catch the first rays the moment dawn breaks.
What botanists have long wondered is just how the sunflower and similar types of flowers manage this mobility. In a study published in Science, a team of researchers at last answer those questions, finding the solutions partly in genes, partly in hormones and partly in the sunflower’s need to make friends with its favorite pollinator—the bee.
What makes the sunflower such a puzzle is that it belongs to a group of flowers that lack what is known as a pulvinus—a thickening at the base of a leaf or other structure that changes its rigidity in response to light. As the sun moves across the sky, different amounts of water flow into different parts of the pulvinus, nudging the leaf in the sunniest direction. The sunflower, with no such structure, should be immobile.
To determine how it moves all the same, a team of investigators headed by plant biologist Hagop Atamian at the University of California began by messing with the sunflower’s mind—or at least its rhythms. Potted sunflowers growing outside were turned 180 degrees as soon as the sun went down. Having bent to face west throughout the day, the flowers would now be facing east and ready for the morning. If they remained pointed that way it would mean that something in the environment was telling them how they were oriented and that they could remain still. If they bent the other way—effectively the wrong way for morning—it would mean that their circadian clock was dictating their motion and that the plants had no idea where they were.
That second possibility was what played out, as the confused plants worked all night to change their direction like they ordinarily would, only to wake up, as it were, and find they were facing the wrong way. So score one for the circadian system.
But light sensitivity—or heliotropism—plays a role too. At the summer solstice, sunflowers move more slowly than they do all year, taking the full 16 hours of available daylight to follow the sun from east to west. In winter, sunflowers grown in greenhouses speed through their daily calisthenics, going east to west in just the eight hours the sun is out. When it’s cloudy, the entire system slows down.
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That awareness of the light has limits, though. Under artificial lighting, the researchers found that they could effectively train plants to follow the peak summer pattern indefinitely, bending east to west over 16 hours to follow a moving light source and then reorienting themselves east during the eight hours of darkness. When the plants were switched from a 24- to a 30-hour cycle, however, they lost their way, unable to track properly until they were returned to a shorter, natural day. In this case, the researchers concluded, circadian rhythms and light sensitivity were in competition, and neither one won.
Determining the mechanism of the motion was the most complex part of the study. Plant genes are known to regulate the level of a hormone called auxin, which causes stems and shoots of plants to lengthen. During the part of a day that a sunflower is tracking west, the auxin-promoting genes are more active on the east side of the stem, pushing the plant the other way. At night, as the plant shifts east, the pattern reverses itself.
The investigators, however, found that auxin does not work alone. Another hormone, called gibberlin, is also in play. One species of sunflower is known to be deficient in gibberlin, leaving it with short stems and unable to track the sun effectively. When the investigators extracted the hormone from full-sized sunflowers and applied it to the dwarf variety, they grew normally and became good sun-trackers.
And how do the bees figure into this? For them it’s mostly about the heat and less about the light. Thermal readings of sunflowers revealed that those that faced the sun in the morning were, no surprise, warmer than those that had been rotated the other way. Bees preferentially landed on those warm sides. When the investigators used space heaters to warm up the cooler flowers, the bees began to land there too—though still not in the same numbers they did on the sun-facing flowers.
All of this, it’s fair to guess, is bigger news to botanists than it is to the rest of us. Still, it was millions of years ago that the sun, the flowers and the bees began their cyclic dance. It’s nice, at last, to be able to follow their story.
Write to Jeffrey Kluger at [email protected]
Types of Flowers That Open With the Sun
morning glory vine image by tomcat2170 from Fotolia.com
Flower gardens come in all shapes and sizes and so do the plant in them. Some flower gardens even include plants whose blooms open in the morning only to close at night. These plants are responding to temperature and light changes. In addition, flowers that open in the daylight often do so as part of the plant’s pollination process. Either way these plants add interest, texture and color to any landscape.
gazania image by leiana from Fotolia.com
Gazania Harlequin Hybrids, also known as Mexican daisies, are often planted as ornamentals along borders or in rock gardens. Gazania daisies produce a ground-hugging ground cover with bright yellow, orange and red flowers that open in the sun and close at night or in overcast conditions. They prefer dry and acidic soil, and full sun. In addition, the University of Florida Cooperative Extension Service notes gazania daisy is a perennial grown in hardiness zone 8 through 11. However, other zones north of zone 8 may use Gazania daisies as an annual. Gazanias can also be used as cut flowers and due to their vivid colors attract butterflies.
volubilis image by Arraial from Fotolia.com
Morning glories, Ipomoea, are one of the most commonly grown flowers that open in the sunlight. These old-fashioned plants grow prolifically throughout the U.S. in hardiness zones 3 through 10 and often self-seed. Morning glories are a fast-growing, climbing annual. They have large funnel shaped flowers and dark green heart shaped leaves. Morning glories prefer well-drained sandy soil and full sun. Morning glories will tolerate some shade but this often produces less blooms. According to the American Horticultural Society, morning glories should be protected from cold and dry winds as well and should not be put out until all threats of frost have passed.
elegant california poppy image by Bettina Baumgartner from Fotolia.com
California poppies, Eschscholzia californica, produces leathery blue-green foliage and vivid orange flowers that open in the sun. These perennials tolerate poor soil conditions and are resistant to drought. However, they do need full sun to flower. California poppies are often used in roadside landscaping, rock gardens as well as hilly landscapes. Because of their adaptability the California poppy is one of the most common poppy cultivars found in North America. The California Poppy is grown in hardiness zones 3 through 9.
Do all flowers close up at night?
Although many flowers close up at night, not all of them do. Those that open their petals during the day and then close them at night are reacting to light or temperature changes. Other flowers, such as tudaylilies, remain open for twenty-four hours. Other flowers have unusual opening and closing habits. Crocuses, poppies, and morning glories, for example, open as the temperature increases during the day and close as the day gets cooler in the late afternoon. The flower called the four-o’clock closes in the morning and opens again late in the afternoon, right around four o’clock. Moonflower, night-blooming jasmine, evening primrose, angel’s trumpet, night phlox, and night-blooming cereus open only at dusk or at night. Some plants also react to touch and close up their leaves and “play dead” if a hand or twig brushes against them. For example, if you touch a mimosa plant, it will fold its leaves and the stalk will droop.
Flowers close their petals at night because they are protecting the pollen and other reproductive parts of the plant that are inside from the cold and rain. Also, many flowers are pollinated by insects and birds that are active during the day, so there is no reason to be open at night. However, some types of flowerssuch as some types of tropical fruit plants and varieties of cactus flowers and related plantsare pollinated by bats at night, and these flowers will be open at night and closed during the daytime.
Why do some flowers close at night?
Categories:Ecology Garden Questions
Many plant species open their flowers in the morning and then close them for the evening. Other species only have their flowers open at night. The term for this trait is nictonasty. The answer may be in the photograph of the California poppy directly below.
Pollen in poppy flower
It is most likely to protect the pollen.
California poppy flowers open to reveal pollen that is small and delicate. Notice how the lower petals cradle the pollen that has fallen from the anthers. The theory is that some plant species have evolved to ensure their flowers are open when the insects that pollinate them are active.
Flowers that close at night include poppies, tulips, crocus, and hibiscus.
A strong case for pollen protection as the reason for nictonasty can be made when one considers many plant species that depend on animals active at night for their pollination close during the day and open at dusk. If a flower is pollinated by bats or moths there is no point in being open when these animals are not active.
Charles Darwin had another idea. He theorized nictonasty was to protect the flowers from freezing. Charles Darwin was fascinated by movement in the opening and closing of plants in response to light. In 1877, Darwin wrote about Oxalis and Euphorbias in his sleep movement research.
How plants open and close their flowers
There are a few different methods plants use. Some plants, such as kalanchoe, actually grow new cells to facilitate petal movement. New cells are produced on the inside of the flower to open it and on the outside of the flower to close it. Other plants grow their lower petals faster than their upper petals, thus forcing the flower to close. This second method is most likely driven by cooler temperatures at night, suggesting to me a response to temperature as opposed to light.
In the case of poppies and most plants that exhibit nictonasty, they do it by pumping water out of the flowers. It is a clever case of wilting, actually. We’ve all seen plants wilt and it is normally a sign we need to water them. Or it may be because of root rot and the plant simply can’t deliver water to the stems and leaves.
What is particularly remarkable about plants that use this method to close their flowers is the only part of the plant affected is the flowers themselves.
It is hard to take a hike this time of year without seeing a new bouquet of flowers. If your hike is late enough in the evening you might find what appears to be sleepy flowers. The petals on these flowers close up tight for the evening. But unlike you and me, these flowers are not sleeping the night away.
Pasqueflower in bloom one early evening in late April. Several of the flowers in this bunch have started to close for the evening.
Why the petals of some flower species close at night is not completely understood. One leading theory is by closing the flower’s pollen and eggs are protected from predators. Another possibility is that the pollen of a closed flower is not weighed down by the accumulation of dew. The advantage of dry pollen is that it is lighter and more easily distributed by insects.
How petals open and close is better understood. Opening and closing is driven by the plant pumping water into cells to expand and contract the size of cells on the inside and outside of the petal. In other words, expanding cells on the outside of the petal while contracting those in the inside will close the flower. The timing of when to open and close is driven by a special internal clock. A light-sensing molecule within the plant alternates between a daytime and nighttime form which establishes a strong internal clock. Pretty cool.