There are many beautiful flowers that start with the letter I that you can add to your garden. This list of plants ranges from cold weather to hot weather species, so everyone should be able to find something that will suit their garden.
We included the important information you need to decide if you can grow these plants yourself in this list of flowers.
To learn more about the various flowers available for your garden, make sure to check out our list of “Flower Names A to Z”.
Flowers That Start With I:
Quick Look
1. Iberis (Candytuft)
- Scientific Name: Iberis sempervirens
- Sun: Full sun
- Water: Keep soil moist
- Size: 9-12 inches (22-30 centimeters)
- Lowest Temperature: -35°F (-37.2°C)
- Toxicity: None
- Colors: Pink, white
2. Ice Blue Calathea
- Scientific Name: Calathea burle-marxii
- Sun: Partial shade, full shade
- Water: Keep soil moist; best suited for humid conditions
- Size: Up to 5 feet (1.5 meters)
- Lowest Temperature: 30°F (-1.1°C)
- Toxicity: None
- Colors: Blue, white
3. Ice Plant
- Scientific Name: Delosperma cooperi
- Sun: Full sun
- Water: Drought tolerant, keep soil dry, needs good drainage
- Size: 3-6 inches (7-15 centimeters)
- Lowest Temperature: -10°F (-23.3°C)
- Toxicity: None
- Colors: Pink, purple, lavender
4. Iceland Poppy
- Scientific Name: Papaver nudicaule
- Sun: Full sun, afternoon shade in hot climates
- Water: Keep soil evenly moist
- Size: 1-2 feet (30-60 centimeters)
- Lowest Temperature: -50°F (-45.5°C)
- Toxicity: None
- Colors: Pink, orange, yellow, white
5. Ilex (Holly)
- Scientific Name: Ilex aquifolium
- Sun: Full sun, partial shade
- Water: Allow soil to dry between waterings
- Size: 30-50 feet (9-15 meters)
- Lowest Temperature: -15°F (-26.1°C)
- Toxicity: Low
- Colors: Green, white
6. Impatiens
- Scientific Name: Impatiens walleriana
- Sun: Partial shade, dappled shade, deep shade
- Water: Keep soil moist
- Size: 0.5-2 feet (15-60 centimeters)
- Lowest Temperature: 30°F (-1.1°C)
- Toxicity: None-
- Colors: Pink, red, burgundy, orange, purple, lavender, white
7. Incarvillea
- Scientific Name: Incarvillea
- Sun: Full sun, partial shade, dappled sunlight
- Water: Keep soil slightly moist
- Size: 1.5-2 feet (45-60 centimeters)
- Lowest Temperature: -15°F (-26.1°C)
- Toxicity: None
- Colors: Pink
8. Inch Plant
- Scientific Name: Tradescantia zebrina
- Sun: Full sun, partial shade
- Water: Keep soil moist, reduced watering in winter
- Size: 6-9 inches (15-22 centimeters)
- Lowest Temperature: 10°F (-12°C)
- Toxicity: None
- Colors: Purple, lavender, white
9. Indian Blanket
- Scientific Name: Gaillardia pulchella
- Sun: Full sun, partial shade
- Water: Keep soil slightly dry
- Size: 1.5-2 feet (45-60 centimeters)
- Lowest Temperature: 2a -50°F (-45.5°C)
- Toxicity: None
- Colors: Red, burgundy, orange, yellow, gold, purple, lavender, brown, copper
10. Indian Paintbrush
- Scientific Name: Castilleja coccinea
- Sun: Full sun
- Water: Keep soil moist
- Size: 0.5-2 feet (15-60 centimeters)
- Lowest Temperature: -30°F (-34°C)
- Toxicity: None
- Colors: Pink, red, yellow, gold, white
11. Indian Pink
- Scientific Name: Lobelia cardinalis
- Sun: Full sun, partial shade
- Water: Keep soil moist, occasionally wet
- Size: 4-5 feet (1-1.5 meters)
- Lowest Temperature: -35°F (-37.2°C)
- Toxicity: Medium, only if eaten in large quantities
- Colors: Pink, red, burgundy, white
12. Indian Shot
- Scientific Name: Canna indica
- Sun: Full sun, partial shade
- Water: Keep soil moist
- Size: 1.5-8 feet (0.3-2.5 meters)
- Lowest Temperature: 15°F (-9.4°C)
- Toxicity: None
- Colors: Red, burgundy, orange, yellow, gold
13. Indigo Plant
- Scientific Name: Indigofera incarnata
- Sun: Full sun, partial shade
- Water: Drought tolerant, allow to dry between waterings
- Size: 1-2.5 feet (30-76 centimeters)
- Lowest Temperature: 0°F (-17.7°C)
- Toxicity: None
- Colors: Pink, purple, lavender
14. Inula
- Scientific Name: Inula helenium
- Sun: Full sun
- Water: Keep soil moist
- Size: 2-6 feet (0.6-1.8 meters)
- Lowest Temperature: -35°F (-37.2°C)
- Toxicity: Low
- Colors: Yellow, gold
15. Ipheion uniflorum (Springstar)
- Scientific Name: Ipheion uniflorum
- Sun: Full sun, partial shade
- Water: Keep soil slightly moist
- Size: 3-16 inches (7-40 centimeters)
- Lowest Temperature: -5°F (-20.5°C)
- Toxicity: None
- Colors: Blue, purple, lavender, white
16. Ipomoea (Morning Glory)
- Scientific Name: Ipomoea
- Sun: Full sun, partial shade
- Water: Keep soil moist
- Size: Vines reaching up to 15 feet (4.5 meters)
- Lowest Temperature: -50°F (-45.5°C)
- Toxicity: Low
- Colors: Pink, blue, purple, lavender, white
17. Ipomopsis (Standing Cypress)
- Scientific Name: Ipomopsis rubra
- Sun: Full sun, partial shade
- Water: Drought tolerant, keep soil slightly moist
- Size: 3-6 feet (0.91-1.8 meters)
- Lowest Temperature: -5°F (-20.5°C)
- Toxicity: None
- Colors: Red, burgundy
18. Iris
- Scientific Name: Iris
- Sun: Full sun
- Water: Drought tolerant, allow to dry between waterings
- Size: Up to 3 feet (91 centimeters), depending on variety
- Lowest Temperature: -35°F (-37.2°C), depending on variety
- Toxicity: Low
- Colors: Pink, red, burgundy, orange, yellow, gold, blue, purple, lavender, white, black
19. Ironweed (Little Ironweed)
- Scientific Name: Cyanthillium cinereum
- Sun: Full sun
- Water: Keep soil moist
- Size: Up to 1 foot (30 centimeters)
- Lowest Temperature: -30°F (-34°C)
- Toxicity: None
- Colors: Purple, white
20. Isatis
- Scientific Name: Isatis tinctoria
- Sun: Full sun
- Water: Keep soil moist
- Size: 2-4 feet (60-121 centimeters)
- Lowest Temperature: -30°F (-34°C)
- Toxicity: None
- Colors: Yellow
21. Isoplexis
- Scientific Name: Isoplexis canariensis or Digitalis purpurea. Both plants are incredibly similar. Some sources identify them as separate plants while others consider them to be the same.
- Sun: Full sun, partial shade
- Water: Keep soil moist
- Size: 2-5 feet (0.6-1.5 meters)
- Lowest Temperature: -30°F (-34°C)
- Toxicity: Highly toxic; consuming any part of the plant can be fatal
- Colors: Pink, purple, lavender, cream, tan, white
22. Italian Aster
- Scientific Name: Aster amellus
- Sun: Full sun
- Water: Keep soil moist
- Size: 1-2 feet (30-60 centimeters)
- Lowest Temperature: -20°F (-28°C)
- Toxicity: None
- Colors: Yellow, blue, purple, lavender
23. Ivy
- Scientific Name: Hedera helix
- Sun: Full sun, partial shade, dappled sunlight, deep shade
- Water: Keep soil moist, occasionally wet
- Size: Vines reaching up to 80 feet (24 meters)
- Lowest Temperature: -25°F (-31.6°C)
- Toxicity: Medium; some varieties cause skin irritation
- Colors: Yellow, gold, green
24. Ivyleaf Geranium
- Scientific Name: Pelargonium peltatum
- Sun: Partial shade
- Water: Keep soil moist
- Size: 1-2.5 feet (30-76 centimeters)
- Lowest Temperature:
- Toxicity: Low; minor skin irritation; poisonous to cats
- Colors: Pink, yellow, gold, white
25. Ixia
- Scientific Name: Ixia
- Sun: Full sun, partial shade
- Water: Keep soil moist
- Size: 10-20 inches (25-50 centimeters)
- Lowest Temperature: 10°F (-12°C)
- Toxicity: None
- Colors: Pink, red, burgundy, yellow, gold, purple, lavender, cream, tan, white
26. Ixiolirion tataricum (Siberian Lily)
- Scientific Name: Ixiolirion tataricum
- Sun: Full sun, partial shade
- Water: Keep soil moist
- Size: 12-16 inches (30-40 centimeters)
- Lowest Temperature: -30°F (-34°C)
- Toxicity: None
- Colors: Purple, lavender
27. Ixora
- Scientific Name: Ixora coccinea
- Sun: Full sun, partial shade
- Water: Keep soil moist
- Size: Up to 3 feet (91 centimeters)
- Lowest Temperature: 35°F (1.6°C)
- Toxicity: None
- Colors: Pink, red, burgundy, orange, yellow, gold
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