Woolly Tidestromia

Tidestromia lanuginosa

About the Plant

Woolly tidestromia is an annual that grows with the monsoon rains. Its leaves are covered with white hairs, making the plant look almost like a white rug on the ground. Each plant can be 3+ feet wide. The older stems are a bright, deep pink, a striking contrast to the rest of the plant. Though you may get a sense of yellow-ness about the plant when the flowers appear, it is always the white leaves you will notice first.

Woolly tidestromia is native to the Southwest, growing in a wide variety of soils and habitats, at elevations below 5,000 feet. It will grow in full sun but also tolerates part shade. This plant needs no care but make sure to let it go to seed naturally if you want the plant in future years. Seeds are not available commercially.

Notes:

  • Woolly tidestromia is also known as honeymat. It does form a mat upon the ground. The reason for "honey"mat is not clear.
  • "lanuginosa" in the scientific name means woolly or downy, a good description of the leaves.

Wildlife value:

  • Woolly tidestromia attracts small insects, including butterflies. A dainty sulfur is shown in the photo below.

More Information

Map of distribution in US

Technical botanical description from SEINet

ID Characteristics

This plant is in the Amaranthaceae - the amaranth or pigweed family.
Woolly tidestromia is a ground-hugging plant with stems reaching to 1.5 feet or more, creating a plant 3+ feet in width. It grows only a few inches high.
The stems are highly branched. Initially covered in white hairs, the older stems lose these hairs, allowing the very deep pink, almost red, coloration to show.

The leaves are opposite and have a petiole up to an inch long. The blade is oval to elliptic and can also be an inch long. Many leaves, especially under the flowers, are small than this.
The leaves are covered in white hairs. On the smaller leaves and young stems the hairs are very close together, making the leaves look white. On the larger leaves, the hairs are more widely spaced and the green can show through. The older stems and leaves may lose these hairs with time as well, appearing much more deep pink and green, respectively, than the younger parts of the plant.
The underside of the leaves have fewer hairs and appear more green than the upper side. Look closely at those hairs (click on photo to enlarge). They are branched, a condition that distinguishes Tidestromia from other native species in the amaranth family.
The flowers of woolly tidestromia are very small, only a bit more than 1/10 of an inch across. There are 5 yellow tepals* and directly opposite them 5 stamen. The flowers are always in a leaf axil, with several flowers clustered together. Click photo to enlarge.
*Older literature calls these sepals, noting that the flowers have no petals. Current literature such as the Flora of North America calls them tepals.