Winter Behavior of Inca and Princess Lilies (Alstroemeria) in Sacramento Zone 9a

Hardiness and Winter Response

Inca lilies (Alstroemeria aurantiaca) are hardy to Zone 7, tolerating brief dips to 10°F. Princess lilies (dwarf Alstroemeria) share similar hardiness but are evergreen only in mild climates. In Sacramento (Zone 9a), both will likely remain evergreen or experience only brief dormancy during cold snaps.

Winter Care Recommendations

• Mulch heavily (3–4 inches of straw or shredded leaves) after first frost to insulate crowns.
• Ensure excellent drainage — wet winter soil causes rot more than cold.
• Do not cut back foliage until spring; it protects the crown.

Varietal Differences

Some cultivars (e.g., ‘Sweet Laura’) are hardy to Zone 5. Check specific variety tags. Cornell notes that many Alstroemeria cultivars lack reliability in colder zones, but your Zone 9a location is well within their comfort range.

Long-Term Performance

With good drainage and winter mulch, both Inca and Princess lilies will thrive and spread slowly via rhizomes, forming colorful, long-blooming clumps for years.