Botany Photo of the Day

Larrea tridentata - Z8 - RHS Index of Garden Plants, Griffiths
Larrea tridentata - Z8-10 - A-Z Encyclopedia of Garden Plants, Brickell, Cole, Zuk

Learn something new every day! I always thought creosote was the buildup remainder from burning wood; I didn't realize it was a plant, itself! Thanks for the continuing education!

I had understood the spacing to be due to a growth inhibitor secreted by the roots; it inhibits the growth of other members of the species as well as of other plants. The inhibitor is apparently water soluble, which is why no grasses or other forbs grow near the plants most of the year, but during the rainy season the ground may be covered between and right up to the individual plants. It was further implied that this inhibitor and its solubility was significant in the preference of the creosote bush for soils with a caliche layer, which was theorized prevented the inhibitor from leaching away too quickly to be useful. I first encountered this explanation in a book (sorry, I do not at this time recall author or title; it was at least thirty years ago) solely and specifically devoted to the creosote bush, its characteristics and economic uses. The reference to the preference for caliche was in a not much more recent issue of _Desert Plants_, the periodical of the Boyce Thompson Arboretum in Arizona.

Beautiful photograph, Daniel. As a person who has spent a lot of time in the desert and Death Valley, I can heartily agree with your comment about the aromatic quality of creosote bush, which is especially noticeable after a light rain. I've never thought it smelled especially like creosote, more like paint thinner to me. Many people don't care for the smell, but I love it. It's plants like this and California bay and California sagebrush that really demonstrate "nasal botany." You might also say something about the clonal characteristic of Larrea tridentata, which in terms of individual plants is one of the oldest around, along with bristlecone pine and another clonal species, Populus tremuloides, the quaking aspen. Thanks for sharing this with us.

It seems to me that I've read somewhere that when creosote bushes have been planted in controlled situations where there was plenty of water, they do not exhibit this degree of spacing, which implies that it is not due to any chemicals produced by the plant, but I can't provide a source for that piece of information either.

How nice.. this photo really shows more than a day-time photo would, I bet. Interesting facts too. Thanks again.

Ah, I'm sorry - this is a black-and-white of a daytime scene. It certainly has that night-time look about it, though! What's missing is the lack of shadows from the moon.

Gorgeous photo. Beautiful depth. I thought I had read - sometime in my distant past - about the use of this plant as a potential fuel source, but now the only articles I can find refer to it as a possible source of 'biomass' because it can be grown on otherwise 'unproductive' land. Ah well.

Does the spacing make the stands immune to having a fire cycle? Is this another reason for longevity of individuals, or clones across a landscape?

Regarding the use as a fuel: Never heard of that one! But it was studied for use as something to do with paint and as an antioxidant for foods during WW2, and it has been used for treating skin infections (apparently verified by testing) and for the external treatment of skin cancers. As to its occurrence on "otherwise unproductive lands," I have a recollection of a publication either by NMSU or by the Jornada Experimental Range describing an experiment where this plant, yucca, and mesquite were hand-cleared from a section of rangeland, which I think was then seeded with native grasses but which in any case did finally sustain a native grass population without intervention. The conclusion suggested was that the problem wasn't unproductive soil but that left to themselves, these shrubs seem to act like a climax population.

Spruce trees in peat bogs in Northern Ontario exhibit a similar wide spacing - it's as if someone drew out a 20 or 30 m grid and planted a tree at each intersection.