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The Xeric Zone > Foundations :: Plant Sources: Choosing the Best Provenance

 

 

 

Plant Sources: Choosing the Best Provenance

David Cristiani

Summary: With increases in large-scale native plant growing, it can be important to plant success for species to be grown from sources most similar to the environment of the final project site.

There are many regional plant nurseries now growing plants native to the southwestern US, and it is becoming easier to use those water-thrifty species on projects, thanks to these efforts on increasingly large scales. Some plants grow in native stands across a large geographic area, including saltbush, desert willow, mesquite, and penstemon. Most times, the grower will select such wide-ranging species from near their own facility, though those same plants may be eventually sold to contractors or other nurseries far away, often at higher with different environments.

 

Some growers are starting to collect seed and cuttings from their plants from a variety of sources, such as locales with unique temperature, precipitation, or elevation patterns, so that they will make a better impact in the final landscape they are destined for. While few individual places are exactly alike, there are also definite patterns that are similar between certain different places, whether in the same state, country, or even globally. These similar places are called ecoregions or biomes by botanists and ecologists, while they are commonly called provenances in horticultural circles. When the grower and seed or cutting collector understands this in regards to where and who they are marketing their plants to, they are able to service the end user better. Admittedly, intensive research is lacking on the relationship between plant provenance and plant hardiness for every species, but there are some plants that seem to exhibit preferences by their ability to thrive best in certain provenances.

 

A great example is Texas honey mesquite, Prosopis glandulosa var. glandulosa, which grows natively from the high plains of Baca and Las Animas Counties of southern Colorado southward into the more humid and subtropical lower plains of the Gulf Coast in northeastern Mexico. I have witnessed severe winter damage on trees originally salvaged from south Texas when grown in Albuquerque, even where not over-watered. Meanwhile, trees from seed collected in Carlsbad or southwest Texas have performed mightily in Albuquerque.

 

One exception to that provenance issue is the commonly used red yucca, Hesperaloe parviflora. It has a narrow natural range, only found in parts of south and west Texas into Chihuahua and Coahuila in northern Mexico. It has proven to consistently perform well across a far wider range of places than its natural range would suggest, though, such as Denver, Phoenix, and Dallas…and it may even work in sunny spots throughout the south and east as far north as Kansas City and New York, where it usually would get the heat it needs in summer and mild enough winters.

 

Finally, some plants, such as the fragrant creosote bush, Larrea tridentata, seems to grow erratically wherever it is adapted, even with careful irrigation. Soil may be the factor in this case, while more precise consideration to duration of heat or timing of moisture may prove to offer another clue. Plants known to have started from seed collected near Phoenix have thrived in Albuquerque, while others grown on seemingly perfect soils for creosote (deep and well-draining, with some caliche) failed miserably in the same city or even the same property. A few may have died from an extremely cold winter at their northern reaches, but reports on this have been unreliable.

 

 

Landscape Locale

Provenance for Likely Success

Provenance for Unlikely Success: be cautious

Provenance for Likely Failure

 

 

Albuquerque, Bernalillo, Belen, Laguna

Colorado Plateau below 5000 feet; Chihuahuan Desert of southern NM / Trans Pecos TX; southern high plains; Mojave Desert

Chihuahuan Desert of Mexico; northern Great Basin Desert; Rocky Mountains above 7500 feet; central US high plains

Sonoran Desert (Phoenix, Tucson, Palm Springs); south TX plains

 

 

Roswell, Lubbock, Clovis

Southern high plains; Chihuahuan Desert of southern NM / Trans Pecos TX

Texas Hill Country; Colorado Plateau below 5000 feet; Mojave Desert

Great Basin Desert; Sonoran Desert; south TX plains

 

 

Santa Fe, Edgewood, Ruidoso

Central US high plains and highlands; Great Basin Desert; Rocky Mountains below 7500 feet

Southern high plains; Rocky Mountains above 10000 feet; Chihuahuan Desert; Mojave Desert; Colorado Plateau below 5000 feet

Sonoran Desert; Texas Hill Country; south TX plains

 

 

Las Cruces, El Paso, Alamogordo, Carlsbad

Chihuahuan Desert; Mojave Desert; southern high plains; Colorado Plateau above 5000 feet

Sonoran Desert; Great Basin Desert; Texas Hill Country; south TX plains

Rocky Mountains; central US high plains

 

 

Tucson, Carefree, north Scottsdale

Sonoran Desert; Chihuahuan Desert; Mojave Desert; Texas Hill Country; south TX plains

Southern high plains; Colorado Plateau below 5000 feet

Great Basin Desert; Rocky Mountains; central US high plains

 

 

 

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