Buddleja macrostachya (Long Spiked Butterfly Bush)


Michael's Opinion

Buddleja macrostachya is an interesting plant known for its vibrant colour and its sweet, honey-like scent. Commonly used as an ornamental garden plant this species is considered weedy in many parts of the United States. Its flowers and fruit can be poisonous to humans if ingested but many gardeners plant it anyway because it attracts such wildlife such as hummingbirds, bumble bees and especially butterflies.

Botanical Information

FamilyScrophulariaceae
GenusBuddleja
Speciesmacrostachya
SynonymsBuddleia
CategoryWoody
TypeShrub (deciduous)
ReferencesLi, P. T. & Leeuwenberg, A. J. M. (1996). Loganiaceae, in Wu, Z. & Raven, P. (eds) Flora of China, Vol. 15. Science Press, Beijing, and Missouri Botanical Garden Press, St. Louis, USA. Grierson, A. J. C., & Long, D. G. (1983). Flora of Bhutan: Including a record of plants from Sikkim. Edinburgh: Royal Botanic Garden.
OriginChina and Vietnam.

Details

USDA Hardiness Zone5 - 10
USDA Hardiness Ref.
Canadian Hardiness Zone6 - 10
Canada Hardiness Ref.
RHS Hardiness ZoneH5
RHS Hardiness Ref.
Temperature (°C)1 - 39
Temperature (°F)34 - 105
Height6 m
Spread6 m
GrowthFast
Flowering PeriodApril, May

Description and Growing Information

General DescriptionThis plant is a large deciduous shrub with dark green leaves, exfoliating bark on older branches and beautiful flower panicles with clusters of cream coloured petals which bloom in the late spring and persist generally into the first winter frost.
ID CharacteristicLarge conical shaped clusters of tubular, four petaled flowers. Very noticeable sweet scent emanates from the nectar of the flowers. Older branches have exfoliating bark.
ShapeVertical, tall growing, weeping shrub that could potentially be a small tree in optimal conditions.
LandscapeBuddleja macrostachya is commonly used as a garden plant for its beautiful white/cream coloured flower panicles and its ability to recover from harsh pruning. The sweet smelling nectar attracts many species of wildlife ranging from butterflies to hummingbirds as well as some moths and honey bees.
PropagationIt can be propagated through seeds or through a semi-hard wood cuttings. If propagated through seed (main form of propagation) it must be sown in the early spring in loose, well-drained soil with added compost and ample space as the plant grows fast and will shade out other plants.
CultivationThis plant is hardy and is not particular about soil conditions, making it easy to grow along roadways and poor to lean soils. However it does best in well drained but soil moist with a slightly alkaline pH. It should be planted in full sun.
PestsThis plant is very disease resistant but attracts pests such as capsid caterpillars and red spider mites. Red spider mites seem to become more of a problem in greenhouse cultivated plants or if the plant is under stress or drought.
Notable SpecimensWestonbirt, The National Arboretum, Tetbury, Gloucestershire, England.
HabitatTypically found in areas of well drained but moist soils, around rivers or slow streams where it can grow in dense clusters and out compete other naturally growing vegetation.
Bark/Stem DescriptionStems are small and square with younger growth showing brown striping and older bark exfoliating.
Flower/Leaf Bud DescriptionBuds are small, generally 3 - 4 mm, and grow in clusters.
Leaf DescriptionElliptical to narrowly elliptical shaped leaves ranging in size from 1.5 - 7 cm with dark, glossy green colour on top and a lighter grey on the bottom coated in small, fuzzy hairs. Leaf margins are finally crenate - serrate with lateral venation.
Flower DescriptionFlowers are tubular in shape with four petals and grow in conical clusters that range from 10 - 30 cm long. The petals are a cream colour on top with an orange throat and anthers. Blooming period takes place in late spring and the flowers will remain until the first frost of winter. This plant has adapted to suit avian pollinators such as hummingbirds.
Fruit DescriptionSmall, capsule shaped fruits, generally 1 cm long and 2 mm wide containing many seeds making it easy for the plant to spread naturally.
Colour DescriptionBuddleja macrostachya is a very colourful plant. Throughout the growing season it is decorated with large panicles of cream and orange coloured flowers and rich green foliage but after the dormant season begins this plant has an interesting brownish grey exfoliating bark that holds winter interest.
Texture DescriptionThis plant has a medium to rough texture.

Photographs