When to Plant Sunflower in Bosque County, TX
Sunflower (Helianthus annuus) is a fast-growing North American native annual famous for its towering stems and brilliant yellow heads. It thrives in full sun and heat, producing large, pollen-rich blooms that attract bees, butterflies, and seed-eating birds. Varieties range from 18-inch dwarfs to 12-foot giants and nearly every color except blue.
Bosque County, Texas is in USDA Zone 8b. The average last spring frost is March 14 and the first fall frost is November 16, giving you a growing season of approximately 247 days.
At an elevation of 1,846 feet, Bosque County receives approximately 64.5 inches of rainfall annually with predominantly clay soil. Summer highs average 93°F, providing good warmth for Sunflower during the growing season. Clay soil retains moisture well for Sunflower, but amend with compost to improve drainage and prevent root rot. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Sunflower root diseases.
Bosque County Soil Profile
Soil Type
Clay
Soil pH
6.8-7.9
Drainage
Well Drained
Monthly Watering Guide for Sunflower
Sunflower needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Sunflower Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.5" | 0" | ❄️ Dormant |
| Feb | — | 2.2" | 0" | ❄️ Dormant |
| Mar | 4.3" | 3.9" | 0.4" | 💧 Light watering |
| Apr | 4.3" | 6.8" | 0" | ✅ Rainfall sufficient |
| May | 4.3" | 8.2" | 0" | ✅ Rainfall sufficient |
| Jun | 4.3" | 10.7" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 9.1" | 0" | ✅ Rainfall sufficient |
| Aug | 4.3" | 7.9" | 0" | ✅ Rainfall sufficient |
| Sep | 4.3" | 6.7" | 0" | ✅ Rainfall sufficient |
| Oct | 4.3" | 4.1" | 0.2" | 💧 Light watering |
| Nov | 4.3" | 1.8" | 2.5" | 🚿 Regular watering |
| Dec | — | 1.7" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Mar–Nov in Bosque County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Sunflower Planting Timeline — Bosque County, TX
Sunflower Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 21 | Feb 21 – Mar 7 |
| Transplant Outdoors | February 28 | Feb 28 – Mar 14 |
| Direct Sow | February 28 | Feb 28 – Mar 21 |
| Bloom | May 23 | May 23 – Oct 10 |
Plant 1" deep · 18" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors Transplant Outdoors Direct Sow |
| March | Start Indoors Transplant Outdoors Direct Sow |
| April | — |
| May | Bloom |
| June | Bloom |
| July | Bloom |
| August | Bloom |
| September | Bloom |
| October | Bloom |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
Low — drought tolerant
📅 Days to Maturity
70–100 days
🧪 Soil pH
Needs 6–7.5 · Your soil: N/A
🗺️ USDA Zone
Zone 8b
📆 Growing Season
247 days in Bosque County
Growing Tips for Bosque County
Direct-sow 1 inch deep after last frost; germination takes 7-14 days at 65-75°F soil. Sunflowers dislike root disturbance so direct sowing is strongly preferred over transplanting. Plant in succession every 2 weeks for extended bloom. Stake tall varieties. Avoid overwatering — they tolerate drought once established. Birds will self-deadhead seed heads; leave them up through fall for wildlife.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Sunflower in Other Locations
Frequently Asked Questions
When should I plant Sunflower in Bosque County, TX?
Bosque County is in Zone 8b with an average last frost of March 14. Plan your Sunflower planting based on this frost date — see the calendar above for exact timing.
What planting zone is Bosque County, TX?
Bosque County, Texas is in USDA Hardiness Zone 8b. The average last spring frost is March 14 and first fall frost is November 16.
Your Bosque County Garden Planner — Free
A 22-page printable planner built for Bosque County (Zone 8b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.