By Robin Y Rivet, for Let's Talk Plants! December 2021.
Desert Willow in bloom – Chilopsis linearis 'Timeless Beauty' cultivar © photo by Robin Rivet (used with permission).
Typically, the word “willow” conjures up deciduous, riparian tree species, encountered in ample rainfall, high humidity regions of the US. The Salix genus includes the iconic weeping willow, as well as numerous local native California species like the arroyo, red pacific and Gooding’s willows. Our native willows make fine host plants for butterfly larvae, but also crave moist growing conditions. Considering that Salix babylonica (the Chinese native weeping willow), drinks too much for our Mediterranean climate, and our CA native riparian willows have been perishing by the 1000’s in the Tijuana river valley from KSHB pest issues; these are seldom useful as urban garden trees.
Are there suitable substitutes? There are divergent answers. You could try growing corkscrew willow - S. matsudana ‘Tortuosa’ in a very, large pot to lure in local butterflies, perhaps even harvesting its twisted limbs for floral arrangements. Regardless, thirsty trees grown in containers require constant vigilance. I tried and failed.
However, if you’re primarily seeking habitat-friendly species, many plants called “willows” do fit that bill - and are highly adapted to our region’s urban forest. Many have comparable weeping habits to willows – with similar architecture, but better drought adaptability.
My first suggestion for wildlife habitat is our own deciduous CA native desert “willow” - Chilopsis linearis. I recently propagated 40 cuttings from my own hybrid cultivar ‘Timeless Beauty’, which is cross-referenced as ‘Monhews’. Although not a true willow, it is a spectacular, small-scale beauty, whose large blooms produce profusely for almost six months in San Diego County’s Sunset Western Zones 21-23, although I’m unsure how well they’d adapt to our coastal Zone 24. In my case, knowing it was a rare cultivar that did not set seed, all my cutting-grown starts went to random recipients who pledged to plant and nurture these one-gallon seedlings to maturity. ‘Timeless Beauty’ attracts many birds and butterflies (and human adoration) - all season long.
There are also three “willow-named” species from Australia. Nichol’s willow-leafed peppermint – Eucalyptus nicholii; the Australian “willow” – Geijera parviflora; and “willow” acacia – Acacia salicina. All of these species are evergreen and need much less liquid to keep them afloat. Nonetheless, each has characteristics to explain their common name moniker. Another western Australian evergreen species is called a ‘willow myrtle”, and is not a willow either, but it is a myrtle. Agonis flexuosa or peppermint tree, tolerates wetter conditions, but is drought tolerant, if a bit frost-sensitive in our coldest regions - mostly when immature. Plus, there is a burgundy-leaved cultivar ‘Jervis Bay Afterdark’.
Willow acacia - Photo: SelecTree. UFEI. "Acacia salicina Tree Record." 1995-2021. Cal Poly State University, San Luis Obispo. Accessed on Nov 15, 2021.
If you don’t care a whit about names, but desire a worthy, weeping tree that attracts wildlife, is low-water use, has well-behaved roots, and tolerance for alkaline soils: there are a few more choices. Callistemon vinimalis - or weeping bottlebrush is one. Another is the weeping acacia – Acacia pendula, and then there’s two conifers: the weeping blue atlas cedar, and Tolleson’s green weeping Rocky mountain juniper. Like willows, all these species have weeping or semi-weeping habits, but they are beautiful, tough evergreen trees, providing all-season shelter for local wildlife.
Photo: SelecTree. UFEI. Juniperus scopulorum 'Tollesons Green Weeping' Tree Record. 1995-2021. Cal Poly State University, San Luis Obispo. Accessed on Nov 15, 2021.
Or - If you prefer harvesting food from a pendulous selection yourself, consider the deciduous weeping mulberry.