When to Plant Coreopsis in Tillamook County, OR
Coreopsis (Tickseed) is a cheerful, long-blooming native perennial that produces a continuous flush of bright yellow, gold, or bi-colored daisy-like flowers from early summer well into fall. One of the most reliable cut-and-come-again bloomers in the perennial garden, it thrives in hot, dry, sunny conditions and poor soil where many competitors struggle. An invaluable nectar source for native bees and butterflies, and a butterfly host plant for several species.
Tillamook County, Oregon is in USDA Zone 9a. The average last spring frost is April 19 and the first fall frost is October 29, giving you a growing season of approximately 193 days.
At an elevation of 332 feet, Tillamook County receives approximately 40.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Coreopsis during the growing season.
Tillamook County Soil Profile
Soil Type
Silt Loam
Soil pH
5.3-6.5
Drainage
Well Drained
Monthly Watering Guide for Coreopsis
Coreopsis needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Coreopsis Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 5.4" | 0" | ❄️ Dormant |
| Feb | — | 4.1" | 0" | ❄️ Dormant |
| Mar | — | 4.1" | 0" | ❄️ Dormant |
| Apr | 4.3" | 3.4" | 0.9" | 💧 Light watering |
| May | 4.3" | 2.5" | 1.8" | 💧 Light watering |
| Jun | 4.3" | 1.8" | 2.5" | 🚿 Regular watering |
| Jul | 4.3" | 0.7" | 3.6" | 🚿 Regular watering |
| Aug | 4.3" | 0.8" | 3.5" | 🚿 Regular watering |
| Sep | 4.3" | 1.8" | 2.5" | 🚿 Regular watering |
| Oct | 4.3" | 3.7" | 0.6" | 💧 Light watering |
| Nov | — | 6.4" | 0" | ❄️ Dormant |
| Dec | — | 6.2" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Tillamook County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Coreopsis Planting Timeline — Tillamook County, OR
Coreopsis Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 22 | Feb 22 – Mar 8 |
| Transplant Outdoors | April 5 | Apr 5 – Apr 19 |
| Direct Sow | April 5 | Apr 5 – Apr 26 |
| Bloom | May 31 | May 31 – Nov 1 |
Plant 0.1" deep · 18" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | Start Indoors |
| April | Transplant Outdoors Direct Sow |
| May | Bloom |
| June | Bloom |
| July | Bloom |
| August | Bloom |
| September | Bloom |
| October | Bloom |
| November | Bloom |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
Low — drought tolerant
📅 Days to Maturity
60–80 days
🧪 Soil pH
Needs 5.5–7.5 · Your soil: N/A
🗺️ USDA Zone
Zone 9a
📆 Growing Season
193 days in Tillamook County
Growing Tips for Tillamook County
Start seeds indoors 8–10 weeks before last frost or direct sow after last frost. Seeds germinate easily without stratification. Thrives in poor to average, well-drained soil — rich soil promotes foliage over flowers. Drought tolerant once established; overwatering is the most common mistake. Deadhead spent blooms to maintain continuous flowering through the season. Shear plants by one-third in midsummer for a fresh flush of late-season blooms. Year 2+ plants bloom most heavily. Divide every 2–3 years in early spring to rejuvenate crowded clumps.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Coreopsis in Other Locations
Frequently Asked Questions
When should I plant Coreopsis in Tillamook County, OR?
Tillamook County is in Zone 9a with an average last frost of April 19. Plan your Coreopsis planting based on this frost date — see the calendar above for exact timing.
What planting zone is Tillamook County, OR?
Tillamook County, Oregon is in USDA Hardiness Zone 9a. The average last spring frost is April 19 and first fall frost is October 29.
Your Tillamook County Garden Planner — Free
A 22-page printable planner built for Tillamook County (Zone 9a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.