Riparian Plants: Blue Elderberry - Sambucus mexicana
Blue elderberry is found in Valley oak woodlands and mixed riparian forests. Blue elderberry is common on moderate and high elevation floodplains where it can grow in sandy to silt loam soils. The roots of elderberry do not have to reach the water table. Blue elderberry is drought deciduous, which means it drops its leaves once the roots no longer have access to adequate moisture, and the shrub remains dormant until soil moisture increases. However, blue elderberry does not tolerate long flooding events.
Blue elderberry can grow in association with many tree and shrub species. Competition for shade and possibly nutrients with other plants affects the growth form of elderberry shrubs. For example, they tend to grow as broad, dense and multi-stemmed shrubs under an open canopy, and more like single stemmed trees under a closed canopy.
Elderberry shrubs provide structure for nests and cover. As a large shrub 2 to 10 meters in height, elderberry shrubs contribute to a midstory layer in riparian plant communities. Frequently these shrubs are highly branched, and the multiple stems of varying sizes provide dense cover for small mammals, birds and reptiles. Blue elderberry is the sole host plant for the Federally Threatened Valley elderberry longhorn beetle. Elderberry foliage, berries and flowers are important food sources for wildlife. The berries provide a late summer food source important for riparian wildlife, especially migratory and resident songbirds.
For more information about the ecological tolerances and structure of riparian plants, see Gaines 1977, Conard and others 1977, Holstein 1984, Sacchi and Price 1988, Faber and Holland 1996, Cooper and others 1999, Vaghti 2003, Fremier and Talley 2009, and Vaghti and others 2009.
Blue Elderberry dimensions