When to Plant Ageratum in Union County, NJ
Your June planting checklist for Union County, New Jersey
Here's what deserves your attention in Union County, New Jersey this month. Everything below is tailored to Zone 7a and timed around your local frost dates.
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It's harvest week for ageratum
Don't tug. Use scissors or pruners for clean cuts — torn stems invite disease.
July prep starts now
- 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.
Union County, New Jersey is in USDA Zone 7a. The average last spring frost is March 29 and the first fall frost is November 12, giving you a growing season of approximately 228 days.
At an elevation of 814 feet, Union County receives approximately 49.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 93°F, providing good warmth for Ageratum during the growing season.
Union County Soil Profile
Soil Type
Silt Loam
Soil pH
4.8-6.5
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 Union County
How your county's soil matches Ageratum's growing requirements.
Soil pH
Your soil pH (4.8–6.5) is more acidic than Ageratum prefers (6.0–7.0). Add garden lime to raise pH.
Soil Texture
The silt loam soil in Union County is excellent for Ageratum — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Drainage is adequate for Ageratum.
Organic Matter
Organic matter is moderate (3.1%). Annual compost additions will help Ageratum.
How to Plant Ageratum
Succession Planting Ageratum
Sow every 6.9 weeks. Last sowing by Aug 29 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 | — | 3" | 0" | ❄️ Dormant |
| Feb | — | 3.2" | 0" | ❄️ Dormant |
| Mar | 4.3" | 4.3" | 0" | ✅ Rainfall sufficient |
| Apr | 4.3" | 4.8" | 0" | ✅ Rainfall sufficient |
| May | 4.3" | 4.2" | 0.1" | 💧 Light watering |
| Jun | 4.3" | 4.3" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 5.4" | 0" | ✅ Rainfall sufficient |
| Aug | 4.3" | 4.4" | 0" | ✅ Rainfall sufficient |
| Sep | 4.3" | 4.1" | 0.2" | 💧 Light watering |
| Oct | 4.3" | 3.9" | 0.4" | 💧 Light watering |
| Nov | 4.3" | 3.7" | 0.6" | 💧 Light watering |
| Dec | — | 4" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Mar–Nov in Union 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 — Union County, NJ
Ageratum Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 15 | Feb 15 – Mar 1 |
| Transplant Outdoors | March 29 | Mar 29 – Apr 12 |
| Direct Sow | March 29 | Mar 29 – Apr 19 |
| Bloom | May 24 | May 24 – Sep 13 |
· 8" apart · Rows 10" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | Start Indoors Transplant Outdoors Direct Sow |
| April | Transplant Outdoors Direct Sow |
| May | Bloom |
| June | Bloom |
| July | Bloom |
| August | Bloom |
| September | Bloom |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1"/week · Natural rainfall sufficient
📅 Days to Maturity
60–75 days
🧪 Soil pH
Needs 6–7 · Your soil: too_acidic
🗺️ USDA Zone
Zone 7a
📆 Growing Season
228 days in Union County
Growing Tips for Ageratum in Union County
Direct sow Ageratum outdoors after March 29 in Union 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.
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 Union County, NJ?
Union County is in Zone 7a with an average last frost of March 29. Plan your Ageratum planting based on this frost date — see the calendar above for exact timing.
What planting zone is Union County, NJ?
Union County, New Jersey is in USDA Hardiness Zone 7a. The average last spring frost is March 29 and first fall frost is November 12.
Your Union County Garden Planner — Free
A 22-page printable planner built for Union 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.