📍 Mount Wilson, CA · Zone 9a · Last frost Friday, February 20, 2026
✏️ ChangeWhen to Plant Blueberry in Mount Wilson, California (91023)
Location
Mount Wilson, California
ZIP Code
91023
USDA Zone
9a
Last Frost
Friday, February 20, 2026
📅 Your 2026 Planting Dates
Direct Sow Outdoors
Friday, January 23, 2026
Based on last frost Friday, February 20, 2026 · Zone 9a
Pro tip: Sow Blueberry directly outdoors 4 weeks before your last frost date.
🌿 Plant Details
☀️ Growing Requirements
☀️
Sun
Full Sun
💧
Water
Regular
Seeds typically germinate in 7-14 days
Ready to Plant Blueberry in Mount Wilson?
Get your seeds now so they're ready by Friday, January 23, 2026.
* Affiliate links — we may earn a small commission at no extra cost to you.
🛠️ Supplies You'll Need
* Affiliate links — we may earn a small commission at no extra cost to you.
Common Blueberry Varieties
Popular cultivars to look for at your local nursery or seed supplier.
Bluecrop
The most widely planted northern highbush variety; reliable yields and excellent flavor.
Sunshine Blue
Compact semi-dwarf variety that tolerates less acidic soil; great for containers.
Pink Lemonade
Novelty variety with pink berries and sweet, unusual flavor; ornamental and edible.
Tifblue
Leading rabbiteye variety for the South; heat-tolerant with excellent production.
Northblue
Half-high variety bred for northern gardens; survives to -30°F under snow cover.
Common Blueberry Problems
What to watch for — and how to fix it before it spreads.
Pests
Small fruit fly that lays eggs in ripening berries; larvae make fruit mushy and unmarketable.
Harvest frequently; use fine mesh netting (1mm); spinosad spray on a 5–7 day schedule.
Fly larva that tunnels through fruit; berries look normal outside but have white larvae inside.
Use yellow sticky traps with ammonium bait; harvest promptly.
Can strip a bush within hours of berries ripening.
Cover with bird netting before berries color up; remove netting after harvest to allow pollinator access.
Diseases
Fungal disease that shrivels berries to tan, mummified shells; spreads via spores on the ground.
Remove mummified fruit; mulch heavily in spring to cover spores; apply fungicide at bud break.
Gray mold on blossoms and young shoots in cool, wet spring weather.
Prune for airflow; avoid overhead watering in bloom; apply copper fungicide at bud swell.
Common Mistakes
Blueberries need soil pH 4.5–5.5; in higher pH, plants are chlorotic and produce little fruit.
Test soil before planting; lower pH with sulfur months in advance; use acidifying fertilizer.
Most blueberries need cross-pollination with a different variety for maximum yield.
Plant at least two different varieties that bloom at the same time.
Blueberries need 2–3 years to establish before producing significant fruit.
Remove all flowers in years 1–2 to direct energy into root and cane development.
🌾 Seed Saving Guide
🪴 Vegetative propagationPropagate vegetatively, not by seed
Propagate by softwood cuttings in late spring — seed-grown plants take many years and rarely match the parent.
Take 4-inch cuttings in June, dip in rooting hormone, and root in perlite under mist.
Frequently Asked Questions
When should I plant Blueberry in Mount Wilson, California? +
In Mount Wilson (Zone 9a), direct sow Blueberry outdoors around Friday, January 23, 2026.
What is the last frost date for Mount Wilson, California? +
The average last spring frost date for Mount Wilson, California (ZIP 91023) is around Friday, February 20, 2026. This is based on NOAA climate normals for USDA Zone 9a.
How long does Blueberry take to grow? +
Blueberry typically matures in about 730 days from direct sowing. In Mount Wilson, that means you can expect harvest around Friday, January 23, 2026 plus 730 days.
Should I start Blueberry indoors or direct sow in California? +
Blueberry does best when direct sown outdoors. In Mount Wilson, sow directly around Friday, January 23, 2026.
📚 More Blueberry Planting Guides
Other Plants for Mount Wilson
Growing Blueberry in Zone 9a
Blueberry (Vaccinium corymbosum) is a popular garden vegetable. In Mount Wilson, California, which is in USDA Hardiness Zone 9a, you should direct sow seeds around Friday, January 23, 2026.
Your average last frost date is Friday, February 20, 2026. Blueberry grows well when direct sown, as it doesn't transplant well or germinates quickly outdoors.