When to Plant Ageratum in Oldham County, TX
Ageratum (Ageratum houstonianum), the floss flower, produces clusters of fluffy, powder-puff blooms in the rare sky-blue and lavender tones difficult to find among warm-season annuals. Compact mounding habit makes it ideal as a front-of-border edging plant. Blooms from early summer through fall with minimal deadheading; heat and humidity tolerant once established.
Oldham County, Texas is in USDA Zone 7a. The average last spring frost is April 19 and the first fall frost is October 18, giving you a growing season of approximately 182 days.
At an elevation of 2,350 feet, Oldham County receives approximately 56 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 94°F, providing good warmth for Ageratum during the growing season. Sandy soil warms quickly in spring — great for early planting — but Ageratum will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Ageratum root diseases.
Oldham County Soil Profile
Soil Type
Sandy Loam
Soil pH
7.2-8.3
Drainage
Well Drained
Monthly Watering Guide for Ageratum
Ageratum needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Ageratum Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 3.4" | 0" | ❄️ Dormant |
| Feb | — | 3.4" | 0" | ❄️ Dormant |
| Mar | — | 3.1" | 0" | ❄️ Dormant |
| Apr | 4.3" | 1.8" | 2.5" | 🚿 Regular watering |
| May | 4.3" | 1.3" | 3" | 🚿 Regular watering |
| Jun | 4.3" | 1.9" | 2.4" | 🚿 Regular watering |
| Jul | 4.3" | 10.4" | 0" | ✅ Rainfall sufficient |
| Aug | 4.3" | 12.7" | 0" | ✅ Rainfall sufficient |
| Sep | 4.3" | 6.7" | 0" | ✅ Rainfall sufficient |
| Oct | 4.3" | 4.7" | 0" | ✅ Rainfall sufficient |
| Nov | — | 3.1" | 0" | ❄️ Dormant |
| Dec | — | 3.6" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Oldham County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Ageratum Planting Timeline — Oldham County, TX
Ageratum Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 8 | Mar 8 – Mar 22 |
| Transplant Outdoors | April 19 | Apr 19 – May 3 |
| Direct Sow | April 19 | Apr 19 – May 10 |
| Bloom | June 14 | Jun 14 – Oct 4 |
· 8" apart · Rows 10" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Transplant Outdoors Direct Sow |
| May | Transplant Outdoors Direct Sow |
| June | Bloom |
| July | Bloom |
| August | Bloom |
| September | Bloom |
| October | Bloom |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
Moderate — regular watering
📅 Days to Maturity
60–75 days
🧪 Soil pH
Needs 6–7 · Your soil: N/A
🗺️ USDA Zone
Zone 7a
📆 Growing Season
182 days in Oldham County
Growing Tips for Oldham County
Start seeds indoors 6–8 weeks before last frost — do not cover seed; it needs light to germinate. Can be direct-sown after last frost once soil warms to 60°F. Transplant or thin to proper spacing after frost danger passes. Deadheading isn't strictly required but tidying spent clusters improves appearance. Provide consistent moisture; drought causes premature setting. Avoid deep shade — blooms best in full sun to light afternoon shade.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Ageratum in Other Locations
Frequently Asked Questions
When should I plant Ageratum in Oldham County, TX?
Oldham County is in Zone 7a with an average last frost of April 19. Plan your Ageratum planting based on this frost date — see the calendar above for exact timing.
What planting zone is Oldham County, TX?
Oldham County, Texas is in USDA Hardiness Zone 7a. The average last spring frost is April 19 and first fall frost is October 18.
Your Oldham County Garden Planner — Free
A 22-page printable planner built for Oldham County (Zone 7a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.