FlowersAgeratum
Ageratum houstonianum
Ageratum is a frost-tender annual with fluffy blue, pink or white flower clusters that is usually started from seed indoors about 8 to 10 weeks before the last spring frost.
How to grow ageratum
Side by side
Pick two or three seeds to see how they grow, side by side: sprouting, spacing, sun, water, frost and pet safety in one table.


Comparing Ageratum vs. Balloon Flower vs. African Daisy
The comparison
| Fact | ![]() | ![]() | ![]() |
|---|---|---|---|
| Difficulty | Easy | Moderate | Moderate |
| Life cycle | Annual | Perennial | Not yet verified |
| Germination time | 7–21 days | Not yet verified | Not yet verified |
| Germination temperature | 24–27 °C75–81 °F | Not yet verified | 18 °C64 °F |
| Sowing depth | On the surface | Not yet verified | Not yet verified |
| Sun | Full sun, partial shade | Full sun, partial shade | Full sun |
| Water | Moderate | Moderate | Low |
| Containers | Yes | Not yet verified | Yes |
| Frost tolerance | Tender (no frost) | Not yet verified | Half-hardy (light frost) |
| Links |
Up close
What each one is, in a few lines, with the full growing guide one click away.
FlowersAgeratum houstonianum
Ageratum is a frost-tender annual with fluffy blue, pink or white flower clusters that is usually started from seed indoors about 8 to 10 weeks before the last spring frost.
How to grow ageratum
FlowersPlatycodon grandiflorus
Balloon flower (Platycodon grandiflorus) is a perennial that is easy to grow from seed in full sun to partial shade. Plants are slow to establish and emerge late in spring.
How to grow balloon flower
FlowersOsteospermum ecklonis
Osteospermum ecklonis, the African daisy, is an evergreen shrub with daisy flowers that have dark blue centres and white-to-indigo petals. It likes full sun and can be sown in spring at 18 °C (64 °F).
How to grow african daisyKeep comparing
Add a third seed, or swap one for a close relative from the same category.

Ageratum vs. African MarigoldAgeratum against another flower
Balloon Flower vs. African MarigoldBalloon Flower against another flower
African Daisy vs. African MarigoldAfrican Daisy against another flower
Ageratum vs. Alpine AsterAgeratum against another flower
Balloon Flower vs. Alpine AsterBalloon Flower against another flower
African Daisy vs. Alpine AsterAfrican Daisy against another flowerThe table, row by row
Every row is a fact from each seed's own profile, lined up so the differences stand out.
Germination time and temperature
How many days the seeds take to sprout, and the temperature range they sprout in.
Sowing depth and spacing
How deep to sow each seed and how far apart the plants should grow. “On the surface” means the seed isn't covered.
Days to maturity and life cycle
How long until the plant is ready, counted from sowing or from transplanting (each value says which). Annuals live one year, biennials two, perennials longer.
Sun and water
Full sun means 6 or more hours of direct sun a day, partial shade a few hours. Water needs are rated low, moderate or high.
Containers, frost tolerance and soil pH
Whether it grows in a pot, with the smallest pot when it's known. Frost tolerance runs from tender (no frost) to hardy. Soil pH 7 is neutral.
Toxicity to cats and dogs
Whether the plant is toxic to cats and dogs.
Quick wins
Days from sowing until the first shoots appear, in good conditions.
Pet friendly
Listed as non-toxic to both cats and dogs. Each seed's page has the details.
Not safe for pets: borage, buckwheat, caraway, carnation and 14 more.
Comparing
Each seed's page explains how to grow it from seed, with facts researched and reviewed by our editors.