What is that?! 10 Neat Things about fasciation
You’re walking through the garden when you spot something truly strange: a stem that’s flat like a ribbon, or a flower with way too many petals crammed into one odd shape. It’s not a new variety, and it’s not a disease. You’ve just discovered fasciation. It is a rare but natural mutation that can cause plants to grow in strange and unexpected ways. Stems may flatten, twist, or split; flower heads might double or become wildly oversized. Some gardeners find it alarming; others see it as a quirky curiosity of the plant world.
Here are 10 neat things to know about fasciation: the science behind it, the plants most likely to show it, and why it might be worth embracing when it shows up in your garden.
1. It’s a mutation, not a disease.
Fasciation is a developmental abnormality that occurs when a plant’s growing tip—called the meristem—starts producing cells in an irregular pattern. It isn’t caused by fungi, viruses or pests, and it doesn’t spread from one plant to another.
2. Flat stems are a classic sign.
Instead of growing upward from a single point, the meristem spreads laterally, creating stems that are flattened, ribbed, or fan shaped. These stems may twist or splitand often look like several stems fused together.
3. Flowers can look wild.
Fasciated blooms are often oversized, oddly shaped or doubled. A coneflower might show a fused or forked central cone; a sunflower could develop a flower head the size of a dinner plate with multiple centres. These strange shapes are usually sterile, but not always.
4. Some plants do it on purpose.
While most fasciation is random, a few plants have been bred to display it consistently. The crested form of cockscomb (Celosia cristata) is the most famous example; it features a ruffled, coral-like flower head that’s the result of a stable fasciated mutation.
5. It’s surprisingly rare.
Fasciation occurs in a very small percentage of plants—typically fewer than one in 10,000. Some species are more susceptible, including delphinium, hosta, foxglove, rudbeckia, and tomato; even then, most plants grow normally.
6. The causes are wide-ranging.
Fasciation may be triggered by physical damage, frost, hormonal imbalances, insect feeding or bacterial infection, especially from Rhodococcusfascians. Chemical exposure or genetic instability can also lead to the condition. Often, the exact cause is never known.
7. You might miss it in the garden.
Not all fasciation is dramatic. It can affect roots, underground stems or interior tissues, so a plant may be fasciated without showing clear symptoms. Sometimes, extra branching or denser growth is the only clue.
8. It can disappear as suddenly as it arrives.
A plant may produce one fasciated stem or bloom and never do it again. In other cases, fasciation recurs over several seasons, especially if environmental stressors are repeated. Many plants recover without any intervention.
9. It’s not necessarily bad.
Fasciated stems can be just as vigorous as normal ones and may produce more flowers or offshoots. While some gardeners find the look unsightly, others appreciate the unusual architecture and leave it alone unless it affects flowering or stability.
10. Scientists are still figuring it out.
Despite years of research, fasciation remains only partly understood. It continues to be a subject of study in plant biology, especially in relation to hormones like auxins and cytokinins, and how they influence cell division and meristem structure.
