Narrowleaf Willow

Salix exigua

Native to:
Canada, Mexico, United States

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Taxonomy

Division:
Magnoliophyta | - Flowering plants
Family:
Salicaceae
Genus:
Salix
Species:
Salix exigua
USDA Symbol:
SAEX

Growth Characteristics

Life Cycle:
Perennial
Growth Habit:
Shrub , Tree
Height:
600 cm
Light Requirements:
Full Sun,Part Shade
Drought Tolerance:
Low
Bloom Months:
apr,may,jun
Bloom Colors:
yellow
Landscaping Shrub:
Yes

Wildlife Benefits

Bees:
★☆☆☆☆ Documented bee visitation (GBIF)
Butterflies & Moths:
★☆☆☆☆ Documented Lepidoptera association (GBIF)
Caterpillars:
★★★☆☆ Recorded caterpillar host plant (HOSTS Database)

Keystone Species Ranking

Caterpillar Keystone:
★★★★★ Butterfly & moth species supported by this genus (NWF)
Pollen Specialist Bee Keystone:
★★★★★ Native pollen specialist bee species supported by this genus (NWF)

Host Plant for Caterpillars

Aristotelia fungivorella, Aristotelia salicifungiella, Buck Moth (Hemileuca maia), Caloptilia stigmatella, Ceanothus Silkmoth (Hyalophora euryalus), Cecropia moth (Hyalophora cecropia), Columbia silk moth (Hyalophora columbia), Elegant Sheep Moth (Hemileuca eglanterina), Io moth (Automeris io), Kaslo silkmoth (Hyalophora "kasloensis"), Lebeau's silk moth (Rothschildia lebeau), Mendocino saturnia moth (Saturnia mendocino), Micrurapteryx salicifoliella, Nevada buck moth (Hemileuca nevadensis), Nevada buckmoth (Hemileuca nevadensis-complex), Phyllonorycter salicifoliella, Polyphemus moth (Antheraea polyphemus), Saturnia homogena, White-lined sphinx moth (Hyles lineata), Acadian Hairstreak (Satyrium acadicum), Mourning Cloak (Nymphalis antiopa), Sylvan Hairstreak (Satyrium sylvinum), Viceroy (Basilarchia archippus), Weidemeyer's Admiral (Basilarchia weidemeyerii), Western Tiger Swallowtail (Papilio rutulus)

Reported Fauna Sightings

Butterflies:Lorquin's Admiral (Limenitis lorquini), Mourning Cloak (Nymphalis antiopa), Viceroy butterfly (Limenitis archippus)

Garden & Ecology Notes

Wildlife Value:
birds, bees, butterflies, small mammals
Fall Color:
yellow
Fire Ecology:
Fire adapted — tolerates or benefits from fire
Fire Notes:
Resprouts vigorously from root crown and extensive root system following fire or mechanical disturbance.

Soil Requirements

Soil Type:
sandy, nutrient-poor, well-drained
pH:
5.5 - 8.0 (slightly acidic to neutral)
Drainage:
tolerates poor drainage
Moisture:
consistently moist
Notes:
Commonly found along riverbanks and floodplains

Propagation & Germination

Stratification:
None required
Germination Time:
7–21 days
Notes:
Seeds are short-lived and must be sown fresh on moist soil; no pretreatment required. Light enhances germination.

The above propagation data sourced from Claude AI

Pre-treatment: For seeds, no stratification is required and they should be sown immediately. For cuttings, they should be 20 cm in length and 7 mm in caliper, with the base recut and 1/3 of leaves or buds removed. Cuttings should be placed in a 2 minute fungicide bath to remove surface pathogens and treated with 1000 ppm liquid IBA.

Establishment: Salix exigua is easily produced by either softwood or hardwood cuttings. Salix has latent preformed root initials present in the stems. The most critical factor in the collection of viable Salix seed is frequent observation of catkin development. For this reason, establishment of stock plants in the nursery provides significant advantages over wild-land collections.

Source: npn.rngr.net