Nature’s Notebook

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Photo for species Larrea_tridentata

The oldest living plant is a creosote bush in the Mojave Desert that is estimated to be between 9,400 and 11,000 years old! Also, the creosote bush is host to over 120 different bee species, with 22 of these species exclusively using this pollen as their food source.

Photo Credit:
© R.A. Howard, Courtesy of Smithsonian Institution, Dept. of Systematic Biology, Botany.

Larrea tridentata

creosote bush
What does this species look like?
What does this species look like?: 

Creosote bush is a multi-stemmed, evergreen shrub generally growing no more than 12 feet tall. Its small, yellow, somewhat showy flowers have both male and female parts and are pollinated by insects or are occasionally self-pollinated.

Creosote bush grows best in gravelly to sandy soils that are well-drained. It is highly drought-tolerant and can tolerate a wide range of temperatures (5 to 120 degrees Fahrenheit). Its typical habitats are valley plains, mesas, arroyos, alluvial fans, and gentle slopes of the southwest deserts.

Where is this species found?
States & Provinces: 
AZ, CA, NM, NV, TX, UT
Which phenophases should I observe?
Leaves

Do you see...?

Young leaves
One or more young, unfolded leaves are visible on the plant. A leaf is considered "young" and "unfolded" once its entire length has emerged from a breaking bud, stem node or growing stem tip, so that the leaf stalk (petiole) or leaf base is visible at its point of attachment to the stem, but before the leaf has reached full size or turned the darker green color or tougher texture of mature leaves on the plant. Do not include fully dried or dead leaves. For Larrea tridentata, young leaves are slightly more glossy than mature leaves.

How many young leaves are present?

Less than 3;3 to 10;11 to 100;101 to 1,000;1,001 to 10,000;More than 10,000

Flowers

Do you see...?

Flowers or flower buds
One or more fresh open or unopened flowers or flower buds are visible on the plant. Include flower buds or inflorescences that are swelling or expanding, but do not include those that are tightly closed and not actively growing (dormant). Also do not include wilted or dried flowers.

How many flowers and flower buds are present? For species in which individual flowers are clustered in flower heads, spikes or catkins (inflorescences), simply estimate the number of flower heads, spikes or catkins and not the number of individual flowers.

Less than 3;3 to 10;11 to 100;101 to 1,000;1,001 to 10,000;More than 10,000

More...

Open flowers
One or more open, fresh flowers are visible on the plant. Flowers are considered "open" when the reproductive parts (male stamens or female pistils) are visible between or within unfolded or open flower parts (petals, floral tubes or sepals). Do not include wilted or dried flowers.

What percentage of all fresh flowers (buds plus unopened plus open) on the plant are open? For species in which individual flowers are clustered in flower heads, spikes or catkins (inflorescences), estimate the percentage of all individual flowers that are open.

Less than 5%;5-24%;25-49%;50-74%;75-94%;95% or more

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Fruits

Do you see...?

Fruits
One or more fruits are visible on the plant. For Larrea tridentata, the fruit is capsule-like and fuzzy with white hairs, and changes from green to dark brown and splits apart into five sections.

How many fruits are present?

Less than 3;3 to 10;11 to 100;101 to 1,000;1,001 to 10,000;More than 10,000

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Ripe fruits
One or more ripe fruits are visible on the plant. For Larrea tridentata, a fruit is considered ripe when it has turned dark brown and has split into five sections.

What percentage of all fruits (unripe plus ripe) on the plant are ripe?

Less than 5%;5-24%;25-49%;50-74%;75-94%;95% or more

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Recent fruit or seed drop
One or more mature fruits or seeds have dropped or been removed from the plant since your last visit. Do not include obviously immature fruits that have dropped before ripening, such as in a heavy rain or wind, or empty fruits that had long ago dropped all of their seeds but remained on the plant.

How many mature fruits have dropped seeds or have completely dropped or been removed from the plant since your last visit?

Less than 3;3 to 10;11 to 100;101 to 1,000;1,001 to 10,000;More than 10,000

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