Succulents can change colors throughout the year based on factors such as water, length of the day, heat, fertilizer, soil, etc. Like other plants, they absorb water and carbon dioxide and transform them into glucose and oxygen through photosynthesis. In this process, pigments called chlorophyll (shows the color green), carotenoid (shows the color yellow to orange), and anthocyanins (shows the color red or purple) play an important role.
Most succulents turn green when grown in the shade because chlorophyll is responsible for capturing sunlight to keep the photosynthesis process going. When placed in the sun or at extreme temperatures, the anthocyanins are in higher concentration in the plant cells. The anthocyanins act as antioxidants that protect plants against overexposure to UV lights and extreme temperatures. It is also known that anthocyanins are more stable at a lower temperature. That is why we often see succulents green in summer and color up during fall and winter.
Like other plants, succulents grow longer stems in the shade, and the leaves are more spread-out. That is simply because all plants want to get more exposure to the sunlight by making themselves broader and closer to the sun.
Overwatered succulents tend to grow leggy stems and spread-out leaves. So, resisting the temptation to water your plant too often is the most efficient way to maintain its size and rosette shape.
Also, many people wonder why the leaves of their succulents are so thin and long and different from plants grown by "experts." That is because when you overwater, your plant tends to grow larger and stretched out, while experts are waterless, and their plants have to store water in their leaves. That is why leaves are fatter and juicier with less water.
Not enough sunlight can make your succulents look green and leggy, yet too much sunlight can cause sun damage. As sun exposure increases, anthocyanins are in higher concentration to protect the plant from sun damage. However, if your local UV rating is too high, you can also protect your plant with a layer of shade cloth with less than 50 % UV block. Alternatively, put the plant in a spot with morning sun and afternoon shade.
The temperature usually goes hand in hand with sunlight. With extreme temperatures, over 90 °F (32 °C) and below 32 °F (0 °C) in most cases, plants can go dormant to adapt to the environment. The growth slows dramatically as they go dormant in summer, and leaves turn into vibrant colors. Also, most rosette succulents close their leaves to a ball shape to reduce evaporation. In winter, when some succulents die back or lose some leaves to protect the root system, some will close up and change color, such as Sempervivums, to protect themselves from the cold winter (darker color attracts heat). If they survive, they will put out new growth when the temperature warms up.
Fertilization is usually not that big of a concern, as most succulents can do well with little to no fertilizer added. However, most succulents will do best when fertilized using water-soluble fertilizer once every two months to encourage growth. The plants may put out new growth and turn green for a while but quickly turn back to vibrant color with enough exposure to sunlight.
- Succupedia: Browse succulents by Scientific Name, Common Name, Genus, Family, USDA Hardiness Zone, Origin, or cacti by Genus