Certain flowers have the remarkable ability to change colour during their lifecycle, creating a visually striking transformation in gardens. This colour shift occurs for various reasons, including changes in soil pH, temperature fluctuations, light exposure, and the flower’s age. Hydrangeas , for instance, can change colour depending on the acidity or alkalinity of the soil, while flowers like morning glories and hibiscus shift shades as they age or in response to environmental conditions.
These changes are not just for aesthetic appeal—many flowers use colour shifts to attract pollinators or signal that they’ve already been pollinated. This captivating process demonstrates the complexity of nature, as flowers adapt their appearance to better survive and reproduce, providing an ever-changing beauty to those who observe them. How do flowers change their colour? The phenomenon of colour-changing flowers occurs due to a combination of biological, chemical, and environmental factors.
Here’s how these fascinating transformations happen: pH levels Many flowers, such as hydrangeas and butterfly peas, change colour in response to the pH levels in the soil or other environmental conditions. In hydrangeas, acidic soil (with a pH below 6) produces blue flowers, while alkaline soil (pH above 7) turns them pink. The pH alters the availability of aluminium ions, which in turn influences the pigments in the petals, called anthocyanins.
Age of the flower Some flowers, like hibiscus and lantana, change colour as they age. This is due to the breakdown of pigments in the petals. For example, the bright pigments may degrade over time, causing a shift from vibrant red or pink to lighter colours such as pale yellow or white.
Temperature and light exposure Morning glories and magnolias change colour throughout the day due to temperature fluctuations and light exposure. Cooler temperatures and increased sunlight can affect the pigmentation, especially in flowers that contain anthocyanins, which are sensitive to environmental conditions. Pollination signals Colour-changing flowers like lantana use their shifting hues as signals to pollinators.
Younger flowers may display a colour attractive to pollinators, such as yellow or white, and once pollination has occurred, they change to a different colour, like pink or red. This transition signals to pollinators that the flower has already been visited, allowing them to focus on unpollinated blooms. Pigment production Many flowers have pigments like anthocyanins and carotenoids, which give them their colour.
These pigments can change due to chemical reactions triggered by various environmental factors. Anthocyanins, responsible for reds, purples, and blues, are highly reactive to changes in pH and temperature, leading to the colour variations seen in flowers like petunias or daylilies. List of flowers that change their colour Hydrangea Hydrangeas are famous for their ability to change colour based on soil pH.
In acidic soil, their flowers turn blue, while alkaline soil causes them to bloom in pink. This incredible variation allows gardeners to experiment with soil treatments for different colours. Morning Glory The blooms of morning glory flowers are known for their daily colour shifts.
They typically open in a vibrant shade of blue or purple in the morning, fading to pink or lavender by the end of the day due to light and temperature changes. Hibiscus Hibiscus flowers can start off one colour and transition to another as they mature. Some varieties change from bright red or pink to a pale yellow or white, a transformation that adds beauty to their already eye-catching blooms.
Four O’Clocks As their name suggests, Four O’Clock flowers open in the late afternoon and display different colours on the same plant. One flower can even showcase multiple shades simultaneously, ranging from yellow to pink and red. Lantana Lantana blooms start as one colour, such as yellow, and gradually transition to pink or orange as they age.
This colour-changing quality makes them a dynamic and vibrant addition to any garden. Rose of Sharon This hibiscus relative changes colours throughout the day. It may begin with a pink hue in the morning, then shift to blue or violet by evening.
These subtle transitions add to its charm. Bougainvillea Bougainvillaea may not change colours as dramatically as other plants, but their bracts (leaf-like structures) can change from pink to magenta or orange to red depending on the plant's maturity and environmental factors. Iris Certain iris varieties, especially hybrid types, are known to change colours as they grow older.
A single bloom may shift from pale yellow to a deeper gold, adding complexity to their graceful appearance. Butterfly Pea (Clitoria ternatea) The butterfly pea flower is another plant that changes colour based on pH. It starts as a bright blue, but when exposed to acidic conditions, the flower can change to pink or purple, making it a popular choice for teas that change colour when lemon juice is added.
Petunia Some varieties of petunias undergo a gradual shift in colour as they bloom. Starting with bright shades like white or yellow, they can transition to pink or violet, creating an ever-evolving garden display. Magnolia Magnolia blossoms, particularly those from certain hybrid species, change from white or pale pink to darker shades of pink or purple as they age.
Their elegant appearance is accentuated by these delicate colour shifts. Virginia Spiderwort The Virginia spiderwort has flowers that can change from blue or violet to a bright magenta depending on the temperature and soil conditions. This makes it a visually interesting choice for gardens.
Balloon Flower (Platycodon) This unique flower begins as a large balloon-shaped bud in white or pale blue. As the balloon opens, the flower can shift to a deeper shade of blue or pink, depending on the variety and environmental factors. Daylilies Many daylilies display colour-changing blooms that start off in one hue and fade to another by the end of the day.
Depending on the variety, you may see shifts from yellow to peach or from orange to pink. Carnations Certain carnation varieties, particularly hybrids, can change colours as they mature. They may begin with light shades like white or pale pink and gradually transition to darker pink, red, or purple, offering beautiful layers of colour.
Also read: List of flowers that do not have any fragrance.
