Black-Eyed Susan vs Onion

Side-by-side plant comparison — which is right for your garden?

Black-Eyed Susan

Rudbeckia hirta

Asteraceae · flowers

Deer ResistantDrought TolerantLow Maintenance

Onion

Allium cepa

Amaryllidaceae · vegetables

EdibleDeer ResistantLow Maintenance

Hardiness Zone Range

Black-Eyed Susan (Zones 3-9)

Onion (Zones 3-9)

Overlap: Both grow in zones 3–9

Detailed Comparison

Feature	Black-Eyed Susan	Onion
Scientific Name	Rudbeckia hirta	Allium cepa
Family	Asteraceae	Amaryllidaceae
Category	flowers	vegetables
Sun	☀️ Full Sun	☀️ Full Sun
Water	💧💧 Medium	💧💧 Medium
Soil	Well-drained	Rich, Well-drained
Height	3'	1' 6"
Spread	1' 6"	4"
Bloom Season	Summer-Fall	Summer
Bloom Color	Yellow	White
Growth Rate	Fast	Medium
Native Region	Eastern North America	Central Asia
Maintenance	Low	Low

Special Traits

Black-Eyed Susan

No — EdibleYes — Deer ResistantYes — Drought Tolerant

Onion

Yes — EdibleYes — Deer ResistantNo — Drought Tolerant

Care Tips

Black-Eyed Susan

✓Deadhead spent blooms to encourage reblooming.
✓Divide clumps every 3-4 years.
✓Tolerates poor soil and drought once established.

Onion

✓Match variety to your latitude — long-day for north, short-day for south.
✓Plant sets or transplants for easiest results.
✓Stop watering when tops fall over.
✓Cure for 2 weeks before storing.

Which Plant Is Right for Your Garden?

Choose Black-Eyed Susan if you want a low-maintenance plant, need drought tolerance, and want deer resistance. It thrives in full sun with medium water in zones 3–9.

Choose Onion if you want a low-maintenance plant, and want deer resistance. It thrives in full sun with medium water in zones 3–9.

Plant them together? Both overlap in zones 3–9. They share similar sun requirements (full sun), making them potential garden companions.

View Black-Eyed SusanProfile →View OnionProfile →

Frequently Asked Questions

Can Black-Eyed Susan and Onion grow in the same hardiness zone?

Black-Eyed Susan grows in USDA zones 3-9, while Onion grows in zones 3-9. Both plants can grow together in zones 3 through 9.

Do Black-Eyed Susan and Onion have the same sun and water needs?

Black-Eyed Susan needs full sun and medium water, while Onion needs full sun and medium water. They share similar growing requirements and can be planted in the same bed.

Which grows taller, Black-Eyed Susan or Onion?

Black-Eyed Susan grows taller at 3' compared to Onion at 1' 6". Black-Eyed Susan spreads 1' 6" while Onion spreads 4".

Are Black-Eyed Susan and Onion deer resistant?

Yes, both Black-Eyed Susan and Onion are considered deer resistant, making them excellent choices for gardens in areas with deer pressure.

Which is easier to maintain, Black-Eyed Susan or Onion?

Both Black-Eyed Susan and Onion have low maintenance requirements. They need a similar level of care including regular attention to watering, pruning, and soil health.

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Detailed Comparison

Feature	Black-Eyed Susan	Onion
Scientific Name	Rudbeckia hirta	Allium cepa
Family	Asteraceae	Amaryllidaceae
Category	flowers	vegetables
Sun	☀️ Full Sun	☀️ Full Sun
Water	💧💧 Medium	💧💧 Medium
Soil	Well-drained	Rich, Well-drained
Height	3'	1' 6"
Spread	1' 6"	4"
Bloom Season	Summer-Fall	Summer
Bloom Color	Yellow	White
Growth Rate	Fast	Medium
Native Region	Eastern North America	Central Asia
Maintenance	Low	Low

Care Tips

Black-Eyed Susan

✓Deadhead spent blooms to encourage reblooming.
✓Divide clumps every 3-4 years.
✓Tolerates poor soil and drought once established.

Onion

✓Match variety to your latitude — long-day for north, short-day for south.
✓Plant sets or transplants for easiest results.
✓Stop watering when tops fall over.
✓Cure for 2 weeks before storing.

Which Plant Is Right for Your Garden?

Choose Black-Eyed Susan if you want a low-maintenance plant, need drought tolerance, and want deer resistance. It thrives in full sun with medium water in zones 3–9.

Choose Onion if you want a low-maintenance plant, and want deer resistance. It thrives in full sun with medium water in zones 3–9.

Plant them together? Both overlap in zones 3–9. They share similar sun requirements (full sun), making them potential garden companions.

Frequently Asked Questions

Can Black-Eyed Susan and Onion grow in the same hardiness zone?

Black-Eyed Susan grows in USDA zones 3-9, while Onion grows in zones 3-9. Both plants can grow together in zones 3 through 9.

Do Black-Eyed Susan and Onion have the same sun and water needs?

Black-Eyed Susan needs full sun and medium water, while Onion needs full sun and medium water. They share similar growing requirements and can be planted in the same bed.

Which grows taller, Black-Eyed Susan or Onion?

Black-Eyed Susan grows taller at 3' compared to Onion at 1' 6". Black-Eyed Susan spreads 1' 6" while Onion spreads 4".

Are Black-Eyed Susan and Onion deer resistant?

Yes, both Black-Eyed Susan and Onion are considered deer resistant, making them excellent choices for gardens in areas with deer pressure.

Which is easier to maintain, Black-Eyed Susan or Onion?

Both Black-Eyed Susan and Onion have low maintenance requirements. They need a similar level of care including regular attention to watering, pruning, and soil health.