Light Needs
Mature Height
Mature Spread
Growing Zones
The True Blue Butterfly Bush is an impressive shrub with deep blue flowers. The bell-shaped blue flowers have orange eyes for added visual interest. The flower clusters have a pyramidal form and gently arch in a breeze. Also known as Buddleja x 'Bostulu', this shrub has attractive, silvery-green foliage.
The True Blue Butterfly Bush is appealing to pollinators and fits nicely into a butterfly garden or makes a lovely flowering hedge. Use this impressive flowering plant as a focal point or part of a mass planting for pollinators. Grow True Blue in a container for flexible placement options on a deck or outdoor entertaining area. The True Blue Butterfly Bush grows in zones 5 through 10.
True Blue Butterfly Bush Care
Plant this butterfly bush in full sun. The ideal location will receive at least 6 hours of direct sunlight. Provide fertile, moist, well-drained soil. Water when the top layer of soil feels dry, and apply a thick layer of mulch to prevent the soil from drying out quickly. Feed the plants every few weeks using a balanced fertilizer.
Trim growth by one-third in the spring when new growth appears. Cutting the branches back cleans up the appearance and encourages a bushier form. Avoid cutting back the shrub in fall, which leaves the shrub more vulnerable to winter damage.
True Blue Butterfly Bush Spacing
True Blue Butterfly Bush plants reach 4 to 6 feet tall and 6 feet wide. Create a continuous hedge and space these plants 4 to 6 feet apart.
True Blue Butterfly Bush Plant Facts
Growing Conditions
- Hardiness ZonesGrowing Zones
- USDA Zones 5 to 10 (perennial); grown as an annual elsewhere (outdoors year-round); grown indoors elsewhere (outdoors year-round); grown in containers elsewhere (grown as a seasonal crop)
- Sun Exposure
- Full Sun (6+ Hours Direct Sun)
- Mature Height
- 4-6 Feet
- Mature Spread
- 6 Feet
- Growth Habit
- , Upright
Flowers & Foliage
- Flower Colors
- , Blue
- Flower Description
- Blue
- Bloom Time
- Summer to Frost
- Blooms On
-
New Wood
?
"Blooms on" tells you which stems produce flowers, which decides when it's safe to prune.
- New Wood: Flowers form on stems that grow this season. Prune in late winter or early spring without losing blooms.
- Old Wood: Flower buds form on last year's stems. Prune right after flowering. Pruning in fall or early spring removes next year's blooms.
- Both New and Old Wood: Blooms on last year's stems and again on new growth, so it flowers even after a hard winter or a mistimed pruning. Prune lightly after the first flush of blooms.
- When to Prune
- Late winter to early spring, before new growth starts
- Foliage Color
- , Green, Silver
- Foliage Description
- Green, Silver
- Foliage Type
- , Deciduous, Variegated
- Seasonal Interest
- , Summer Flowering, Fall Flowering, Fall Interest, Winter Interest
Garden Benefits
Plant Overview
- Common Name
- True Blue Butterfly Bush
- Also Known As
- Summer Lilac
- Botanical Name
- Buddleia hybrid 'Bostulu' PP 25,708
Simple Plant Spacing Calculator
Please Note: The pictures below are to give a general representation of the different container sizes. The actual size/ages of plants are estimates and will vary based on type of plant, time of year, last pruning & many other factors.
Also Known As:
Quart
Plant Age:
~ 6 months - 1 year
Plant Size:
~ 4"-8"
Pot Size:
~ 4.75"H x 4.5"W
Volume:
1.50 quarts
Also Known As:
2.5 Quart Pot
Plant Age:
~ 1 - 2 years old
Plant Size:
~ 8"-12"
Pot Size:
~ 6.5"H x 6.5"W
Volume:
2.20-2.30 quarts
Also Known As:
#1 Container
1 Gallon
Plant Age:
~ 1 - 2 years old
Plant Size:
~ 10"-14"
Pot Size:
~ 7"H x 7.75"W
Volume:
2.26-3.73 quarts
Also Known As:
#2 Container
2 Gallon
Plant Age:
~ 1.5 - 3 years old
Plant Size:
~ 12"-18"
Pot Size:
~ 9.5"H x 9.5"W
Volume:
1.19-1.76 gallons
Also Known As:
#3 Container
3 Gallon
Plant Age:
~ 2 - 4 years old
Plant Size:
~ 12"-30"
Pot Size:
~9.5"H x 11"W
Volume:
2.32-2.76 gallons
Also Known As:
#5 Container
5 Gallon
Plant Age:
~3-4 years old
Plant Size:
~ 20" - 60"
Pot Size:
~11" H x 10 1/2” W
Volume:
3.5 - 4 gallons
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We want your plants to arrive in great condition! If you notice any issues upon delivery, contact us within 3 days.
Starting January 1, 2026 all bushes, perennials & trees purchased come with an extended 1-year warranty for added confidence. If your plant dies due to a health issue within a year, we’ll make it right.
Plants that are currently in stock typically ship within 2-7 business days after your order is placed.
Plant Addicts ships to the lower 48 states within the U.S. Unfortunately, we do not currently ship to Alaska, Hawaii, or internationally.
This plant cannot be shipped to the following states: Oregon, AK, HI. These restrictions apply only to this specific plant due to agricultural regulations or other limitations. Other plants may still be available for shipping to these states.
If you have any questions about shipping restrictions, feel free to reach out to our team!