American bellflower
Campanulastrum americanum · Campanulaceae
American bellflower (Campanulastrum americanum) is a annual herbaceous plant in the Campanulaceae family. It is native to North America. USDA records it as hardy in zone 12 and warmer, down to about 52°F.
At a glance
| Type | forb-herb USDA |
|---|---|
| Lifecycle | annual USDA |
| Native status | native USDA |
| Mature height | 6 ft USDA |
| Light | shade USDA |
| Water need | medium USDA |
| Growth rate | rapid USDA |
| Soil pH | 5.5–7.5 USDA |
| Bloom | June–August USDA |
| Flower color | Blue USDA |
| Hardiness zones | 12 and warmer USDA |
| Guild layer | understory Derived |
| Nursery availability | Contracting Only USDA |
USDA quoted from the USDA PLANTS database · Derived computed by a fixed rule from those columns. No value on this page is estimated.
Growing conditions
It tolerates full shade. USDA rates it as having moderate water needs. It is recorded on soils from pH 5.5 to 7.5 — a broad range that spans acidic through mildly alkaline ground. Its cold limit is zone 12; USDA publishes no warm-end limit, so gardeners in warmer zones should check local heat tolerance separately.
Size and growth
At maturity it reaches about 6 ft, making it a low to knee-height plant. It grows quickly, which matters when you are timing a planting around the layers above it.
Bloom period
USDA records a bloom period of June through August. The flower color USDA records is blue. Bloom timing is how the Guild Builder overlaps flowering across a planting so something is in flower for as much of the season as possible.
Bloom period is a claim about when this plant flowers. It is deliberately not a pollinator rating — no dataset we trust publishes one, so we do not make that claim. See Data & sources.
Role in a guild
Understory. In a layered planting this is the layer beneath the canopy, tall enough to hold structure but shaded from above. We derive the layer from the plant's growth habit and mature height using a fixed rule, so the same inputs always produce the same layer.
Tags
Related plants
Similar role and hardiness
- wili wili Erythrina sandwicensis
- common sunflower Helianthus annuus
- foxtail millet Setaria italica
Where this data comes from
Every value on this page comes from the USDA PLANTS database record for symbol CAAM18, or is computed from those values by a fixed rule. Nothing here is estimated or model-generated. Where USDA publishes no value, this page omits the claim rather than filling the gap.
bloom_end— quoted from USDA PLANTSbloom_start— quoted from USDA PLANTScommercial_availability— quoted from USDA PLANTSduration— quoted from USDA PLANTSflower_color— quoted from USDA PLANTSgrowth_habit— quoted from USDA PLANTSgrowth_rate— quoted from USDA PLANTSguild_role— derived by rule from USDA columnsmature_height_ft— quoted from USDA PLANTSmoisture— quoted from USDA PLANTSnative_status— quoted from USDA PLANTSnitrogen_fixer— quoted from USDA PLANTSpet_safe— quoted from USDA PLANTSph_max— quoted from USDA PLANTSph_min— quoted from USDA PLANTSshade_tolerance— quoted from USDA PLANTStemperature_min_f— quoted from USDA PLANTSzone_min— quoted from USDA PLANTS
Read our full data sources and methodology.
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