|
the XERIC ZONE |
|
Quercus : : : 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 |
|
|
Copyright
© 2006 Quercus; Usage Policy |