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When to Plant Ageratum in USDA Zone 8b

Zone 8b Zone 8b June

June to-do list for Zone 8b

Here's what deserves your attention in Zone 8b this month. Everything below is tailored to Zone 8b and timed around your local frost dates.

Avg. last frost March 16
Avg. first frost November 13
  1. Bring in the ageratum

    The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.

July will be here before you know it — start on
  • First harvests: ageratum
Get your free Zone 8b 2026 Planting Guide →

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.

In Zone 8b, the average last spring frost is around February 25 and the first fall frost is around November 28, giving you a growing season of approximately 276 days.

Annual Blooms in Multi-season Pollinator-friendly Good for cutting
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Zone 8b Year-round
276 days
Last Spring Frost February 25
276 growing days
First Fall Frost November 28

Ageratum Planting Timeline — Zone 8b

Where Is USDA Zone 8b?

The map below highlights the states that contain Zone 8b. Click any state to see the Ageratum planting schedule for that location.

Prints a clean, ink-friendly version without maps or navigation.

Ageratum Planting Calendar — Zone 8b

Activity When Date Range
Start Indoors January 14 Jan 14 – Jan 28
Transplant Outdoors February 11 Feb 11 – Feb 25
Direct Sow February 11 Feb 11 – Mar 4
Bloom April 8 Apr 8 – Sep 9

· 8" apart · Rows 10" apart

Month-by-Month Timeline

MonthActivities
January Start Indoors
February Transplant Outdoors Direct Sow
March Direct Sow
April Bloom
May Bloom
June Bloom
July Bloom
August Bloom
September Bloom
October
November
December

Free Zone 8b Planting Calendar PDF

Know exactly when to plant every crop in your zone. Get a printable month-by-month calendar customized for Zone 8b with start dates, transplant windows, and harvest times.

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Growing Conditions

Sun

Full Sun (6-8+ hours)

💧 Water

Moderate — regular watering

Days to Maturity

60–75 days

Soil pH

6 – 7

Zone Temperature Range

15°F to 20°F average annual minimum

Growing Season

276 days (Zone 8b average)

Planting Specifications

Plant Spacing8 inches apart
Row Spacing10 inches between rows

Succession Planting Ageratum in Zone 8b

5
successive plantings in Zone 8b's ~276-day season

Sow every 6.9 weeks for continuous harvest throughout the season.

Growing Tips for Ageratum in Zone 8b

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

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Saving Ageratum Seeds

Recommended for Your Garden

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Seed Starting Trays $8-20

Start seeds indoors with reusable cell trays and humidity domes.

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Soil Test Kit $12-25

Test your soil pH, nitrogen, phosphorus, and potassium levels before planting.

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Garden Plant Markers $6-12

Keep your garden organized with durable, weather-resistant plant labels.

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Frequently Asked Questions

When should I plant Ageratum in Zone 8b?

In Zone 8b, plan your Ageratum planting around the average last frost date of February 25. Start seeds indoors around January 14. Direct sow outdoors around February 11. Transplant seedlings around February 11.

Can Ageratum grow in Zone 8b?

Yes, Ageratum can grow well in Zone 8b, hardy in USDA zones 3a through 11b. Zone 8b has a growing season of approximately 276 days, which is sufficient for Ageratum (60-75 days to maturity).

When can I harvest Ageratum in Zone 8b?

In Zone 8b, expect to harvest Ageratum from April 8 – September 9. Ageratum takes 60-75 days from planting to harvest.

What is the last frost date for Zone 8b?

The average last spring frost in Zone 8b is around February 25, and the first fall frost is around November 28. This gives a growing season of approximately 276 days. These are 50% probability dates — actual frost dates vary year to year.

What should I plant next to Ageratum?

Good companion plants for Ageratum include Marigolds, Zinnias, Petunias, Salvia. These companions can help with pest control, pollination, and nutrient sharing.

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Your Zone 8b Garden Planner — Free

A 22-page printable planner tailored to Zone 8b. Planting dates, monthly task lists, harvest log, seed inventory, and succession charts — everything you need to plan a full season.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals, University Cooperative Extension planting guides. Planting dates are estimates based on average frost dates — local conditions may vary. Last updated: June 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.