When to Plant Ageratum in Malheur County, OR
June in the garden — Malheur County, Oregon
Here's what deserves your attention in Malheur County, Oregon this month. Everything below is tailored to Zone 6b and timed around your local frost dates.
To set up a strong July, finish these tasks
- Starting indoors: ageratum
- First harvests: ageratum
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.
Malheur County, Oregon is in USDA Zone 6b. The average last spring frost is May 18 and the first fall frost is September 29, giving you a growing season of approximately 134 days.
At an elevation of 2,676 feet, Malheur County receives approximately 17.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 90°F, providing good warmth for Ageratum during the growing season. With low rainfall, drip irrigation is essential for growing Ageratum successfully. Mulch heavily to conserve soil moisture.
Malheur County Soil Profile
Soil Type
Silt Loam
Soil pH
5.4-6.3
Drainage
Well Drained
Ageratum Planting Risk Windows
Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.
Soil Compatibility in Malheur County
How your county's soil matches Ageratum's growing requirements.
Soil pH
Your soil pH (5.4–6.3) is more acidic than Ageratum prefers (6.0–7.0). Add garden lime to raise pH.
Soil Texture
The silt loam soil in Malheur County is excellent for Ageratum — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Drainage is adequate for Ageratum.
Organic Matter
Organic matter is excellent (5.6%) — Ageratum will thrive.
How to Plant Ageratum
Succession Planting Ageratum
Sow every 6.9 weeks. Last sowing by Jul 16 to harvest before frost.
Ageratum Water Budget
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 | — | 2.4" | 0" | ❄️ Dormant |
| Feb | — | 1.7" | 0" | ❄️ Dormant |
| Mar | — | 1.9" | 0" | ❄️ Dormant |
| Apr | — | 1.2" | 0" | ❄️ Dormant |
| May | 4.3" | 0.9" | 3.4" | 🚿 Regular watering |
| Jun | 4.3" | 0.7" | 3.6" | 🚿 Regular watering |
| Jul | 4.3" | 0.3" | 4" | 🚿 Regular watering |
| Aug | 4.3" | 0.3" | 4" | 🚿 Regular watering |
| Sep | 4.3" | 0.8" | 3.5" | 🚿 Regular watering |
| Oct | — | 1.4" | 0" | ❄️ Dormant |
| Nov | — | 2.6" | 0" | ❄️ Dormant |
| Dec | — | 3.2" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Sep in Malheur County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Ageratum Heat Requirements (GDD)
What are Growing Degree Days (GDD)?
Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.
Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.
Ageratum Planting Timeline — Malheur County, OR
Ageratum Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 30 | Mar 30 – Apr 13 |
| Transplant Outdoors | May 18 | May 18 – Jun 1 |
| Direct Sow | May 18 | May 18 – Jun 8 |
| Bloom | July 13 | Jul 13 – Oct 26 |
· 8" apart · Rows 10" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Start Indoors |
| May | Transplant Outdoors Direct Sow |
| June | Transplant Outdoors Direct Sow |
| July | Bloom |
| August | Bloom |
| September | Bloom |
| October | Bloom |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1"/week · 2-3 times/week
📅 Days to Maturity
60–75 days
🧪 Soil pH
Needs 6–7 · Your soil: too_acidic
🗺️ USDA Zone
Zone 6b
📆 Growing Season
134 days in Malheur County
Growing Tips for Ageratum in Malheur County
Direct sow Ageratum outdoors after May 18 in Malheur County when soil has warmed and frost danger has passed.
Common pests for Ageratum in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.
Malheur County receives only 18" of rain annually. Ageratum needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.
General growing tips
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 Malheur County, OR?
Malheur County is in Zone 6b with an average last frost of May 18. Plan your Ageratum planting based on this frost date — see the calendar above for exact timing.
What planting zone is Malheur County, OR?
Malheur County, Oregon is in USDA Hardiness Zone 6b. The average last spring frost is May 18 and first fall frost is September 29.
Your Malheur County Garden Planner — Free
A 22-page printable planner built for Malheur County (Zone 6b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.