Ambrosia dumosa aka Bur Sage

Ambrosia dumosa is a small, round shrub. It belongs to the Asteraceae family. It is native to the southwestern United States and northwestern Mexico. Kew places it in deserts or dry shrubland. Virginia Tech gives its height as under 3 feet [0.91 metres]. Its round form and low height give it its shape. The sources describe a shrub of dry land with small leaves. It may shed its leaves in drought, leaving bare branches. A plant with no leaves can still match this species.

The leaves grow in turns along stems, not in pairs. Their shapes vary, so they do not all look alike. Some are simple leaves, while others have deep lobes. Others are multi-pinnately compound: they split into parts, which split again. The edges have coarse teeth or cuts like a saw. Both sides are green beneath a thick coat of pale hairs. These hairs play a key role in how leaves look. The leaves are tiny and may be absent in drought. Leaf shape alone does not show the full range described here.

The thin, stiff twigs have a coat of gray hairs. Narrow scars show where leaves once grew on the twigs. These traits still help when the plant has no leaves. The bark is reddish brown and grows smooth and shiny. Bark and twigs thus give you different traits to check. The bark feels smooth, while hairs cover the thin twigs. These traits and the round shape help describe the shrub. They also give you things to check when flowers are absent.

The dull yellow-green flowers grow in small groups. These groups sit along a spike, not in one large bloom. Virginia Tech gives the bloom time as late winter through early spring. The fruit is a bur with thin spines. It grows to about 0.03 feet [0.01 metres] long. Flower color, spike shape, and spiny fruit also help identify it. The sources give no garden care or hardiness range. They give no basis to judge food use or toxicity. They also do not report pest or disease risks. These gaps do not mean the plant is safe to eat.