When to Plant Sunflower in Hill 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.
Hill County, Texas is in USDA Zone 8b. The average last spring frost is March 12 and the first fall frost is November 19, giving you a growing season of approximately 252 days.
At an elevation of 2,597 feet, Hill County receives approximately 54.7 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.
Hill County Soil Profile
Soil Type
Clay
Soil pH
7.3-7.7
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 | — | 1.5" | 0" | ❄️ Dormant |
| Mar | 4.3" | 3.6" | 0.7" | 💧 Light watering |
| Apr | 4.3" | 5.9" | 0" | ✅ Rainfall sufficient |
| May | 4.3" | 6.7" | 0" | ✅ Rainfall sufficient |
| Jun | 4.3" | 9.7" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 7.3" | 0" | ✅ Rainfall sufficient |
| Aug | 4.3" | 7" | 0" | ✅ Rainfall sufficient |
| Sep | 4.3" | 4.8" | 0" | ✅ Rainfall sufficient |
| Oct | 4.3" | 3.5" | 0.8" | 💧 Light watering |
| Nov | 4.3" | 2" | 2.3" | 🚿 Regular watering |
| Dec | — | 1.4" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Mar–Nov in Hill County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Sunflower Planting Timeline — Hill County, TX
Sunflower Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 19 | Feb 19 – Mar 5 |
| Transplant Outdoors | February 26 | Feb 26 – Mar 12 |
| Direct Sow | February 26 | Feb 26 – Mar 19 |
| Bloom | May 21 | May 21 – Oct 8 |
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
252 days in Hill County
Growing Tips for Hill 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 Hill County, TX?
Hill County is in Zone 8b with an average last frost of March 12. Plan your Sunflower planting based on this frost date — see the calendar above for exact timing.
What planting zone is Hill County, TX?
Hill County, Texas is in USDA Hardiness Zone 8b. The average last spring frost is March 12 and first fall frost is November 19.
Your Hill County Garden Planner — Free
A 22-page printable planner built for Hill 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.