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When to Plant Ageratum in USDA Zone 10b

Zone 10b Zone 10b June

Zone 10b gardeners: here's your June plan

Welcome to June in Zone 10b. These are the moves that will have the biggest impact on your growing season.

Avg. last frost February 13
Avg. first frost November 27
  1. Pick ageratum

    Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.

Looking ahead to July
  • First harvests: ageratum
Send me my free Zone 10b 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 10b, the average last spring frost is around January 1 and the first fall frost is around December 31, giving you a growing season of approximately 364 days.

Annual Blooms in Multi-season Pollinator-friendly Good for cutting
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Zone 10b Year-round
365 days
Last Spring Frost No frost
365 growing days
First Fall Frost No frost

Ageratum Planting Timeline — Zone 10b

Where Is USDA Zone 10b?

The map below highlights the states that contain Zone 10b. 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 10b

Activity When Date Range
Start Indoors November 20 Nov 20 – Dec 4
Transplant Outdoors November 20 Nov 20 – Dec 4
Direct Sow November 20 Nov 20 – Dec 11
Bloom January 15 Jan 15 – Aug 13

· 8" apart · Rows 10" apart

Month-by-Month Timeline

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

Free Zone 10b Planting Calendar PDF

Know exactly when to plant every crop in your zone. Get a printable month-by-month calendar customized for Zone 10b 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

35°F to 40°F average annual minimum

Growing Season

365 days (Zone 10b average)

Planting Specifications

Plant Spacing8 inches apart
Row Spacing10 inches between rows

Succession Planting Ageratum in Zone 10b

7
successive plantings in Zone 10b's ~365-day season

Sow every 6.9 weeks for continuous harvest throughout the season.

Growing Tips for Ageratum in Zone 10b

Zone 10b offers a long growing season (~365 days). You can plant Ageratum earlier and may get multiple harvests.

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.

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Saving Ageratum Seeds

Recommended for Your Garden

☀️
Garden Shade Cloth $15-35

Reduce heat stress and sun scorch in hot climates with UV-stabilized shade cloth.

🌱
Seed Starting Trays $8-20

Start seeds indoors with reusable cell trays and humidity domes.

🧪
Soil Test Kit $12-25

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

Related Plants

Frequently Asked Questions

When should I plant Ageratum in Zone 10b?

In Zone 10b, plan your Ageratum planting around the average last frost date of January 1. Start seeds indoors around November 20. Direct sow outdoors around November 20. Transplant seedlings around November 20.

Can Ageratum grow in Zone 10b?

Yes, Ageratum can grow well in Zone 10b, hardy in USDA zones 3a through 11b. Zone 10b has a growing season of approximately 364 days, which is sufficient for Ageratum (60-75 days to maturity).

When can I harvest Ageratum in Zone 10b?

In Zone 10b, expect to harvest Ageratum from January 15 – August 13. Ageratum takes 60-75 days from planting to harvest.

What is the last frost date for Zone 10b?

The average last spring frost in Zone 10b is around January 1, and the first fall frost is around December 31. This gives a growing season of approximately 364 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.

🌱

Your Zone 10b Garden Planner — Free

A 22-page printable planner tailored to Zone 10b. 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.