Once upon a time velvetleaf
was not considered a big problem in row crops, especially in corn. In the early 1960's
trifluralin was introduced and soybean acres and production increased rapidly throughout
the midwest US. Trifluralin allowed farmers to get effective broad spectrum weed control,
especially with their grasses. But, as this was occurring, velvetleaf spread and increased
throughout this region, causing some growers to be convinced that the trifluralin cans
contained velvetleaf seed. It was a good example of a population shift induced by
eliminating previous weedy competitors or velvetleaf, and allowing this bare ground to be
exploited by the new species. This is a theme that has been reinacted over and over again
since after WWII.
It is called velvetleaf because the leaves and stems have a very soft, downy, feel to the touch. This softness is caused by many fine, small hairs (pubescence). It goes by other names including buttonweed and witch's teat. The mallow family includes cotton.
Explore the menu below to find out more about this fascinating and very competitive weed: Velvetleaf Adaptation & Stress
Seed of velvetleaf is relatively large for a weed species. It relies on a thick, tough, hard seed coat to survive in the soil seed bank. It can live in the soil easily for 50 or more years, one of the longer soil longevities amongst weed species. The seed:
Leaves of velvetleaf are very large, capturing much sunlight (left), even when very young (middle), as well as being covered with a fine, soft hairs (right):
On the left is a velvetleaf mutant, as indicated by the yellow sectored leaves. This type of mutant is called a leaf chimera, meaning it has different genes in different tissues. The yellow sectors arise because some parts of the leaf don't get the right message during development and cells in those areas don't form properly (missing leaf cell layers or chlorophyll).
The seedheads, or capsules develop at the stem-leaf junctions on the upper part of the plant:
Flowers of velvetleaf are a bright yellow, very beautiful if you don't think about what they imply:
The capsules can hardly be considered beautiful:
Below is a closer look at one section of the capsule that I separated out: