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Buddleja, Genus, spp., Multiple species,

Genus
Multiple species

butterfly bushes and allies

Scrophulariaceae The Americas, Asia, and Africa

Attracts Pollinators Attracts Butterflies Attracts Hummingbirds Drought Tolerant Fragrant (moderate)

SunFull Sun

WaterLow · drought-tolerant

HardinessZones 5–9

Overview

Buddleja is a genus of about 100 species of shrubs, with a few small trees and climbers, in the family Scrophulariaceae, native to the Americas, Africa, and Asia. The plants are mostly fast-growing, with arching stems 3–15 feet (1–5 m) tall and paired, often grey-green leaves that are felted beneath in many species. Small tubular flowers are massed into dense, often cone-shaped panicles and carry a honey scent that draws butterflies, bees, and moths; flower colour ranges through purple, lilac, white, pink, and the orange-yellow of B. globosa. Among the species, B. davidii blooms from summer into autumn on the current season's growth. That same vigour and the production of large amounts of wind-blown seed have made B. davidii an invasive weed in parts of Europe, North America, and New Zealand, where it colonises railways, riverbanks, and waste ground. Most species are deciduous in cold climates and evergreen in warm ones. Plants grow in full sun and well-drained soil and tolerate poor, dry ground once established. After hard frost, top growth of the shrubby species may die back and regrow from the base.

Native Range

Buddleja is native to the Americas, Asia, and Africa, with major concentrations in China and in the Andes of South America. Species grow on rocky slopes, riverbanks, forest edges, and disturbed open ground.

Suggested Uses

Buddleja is planted in shrub borders, wildlife and pollinator gardens, and on dry banks for its scented, nectar-rich flowers. Compact cultivars are grown in containers and small gardens. In regions where B. davidii is invasive, sterile or low-seeding cultivars are used in place of the wild form.

How to Identify

Identify Buddleja by its dense, elongated or rounded panicles of small tubular flowers and its paired leaves, which are often grey and felted on the underside. The four-lobed flowers carry a sweet scent and a small eye of contrasting colour at the throat. Arching stems and rapid regrowth after cutting are typical of the shrubby species.

Appearance

Size & Dimensions

Height3' - 15'

Width/Spread3' - 12'

Colors

Flower Colors

Foliage Colors

Fall Foliage Colors

Bloom Information

Bloom Period

~10 weeks

Flowers: June–September

Summer Fall

Most shrubby species flower from early summer into autumn, with B. davidii blooming on growth made the same season. Spring-flowering species such as B. globosa bloom on the previous year's wood. The long flowering period and nectar-rich blooms draw butterflies, bees, and moths over many weeks.

Detailed Descriptions

Flower Description

Purple, lilac, white, pink, or yellow

Foliage Description

Green to grey-green

Growing Conditions

Sun Requirements

SunFull Sun

Requires 6-12 hours of direct sunlight daily

• Full Sun: 6+ hours of direct sunlight

• Partial Shade: 3-6 hours of direct sunlight

• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range5.5 - 7.5 (Acidic to alkaline)

3579

Soil Types

loam sand chalk

Drainagewell drained

Water & Climate

Water Needs

Low

Frost Tolerance

hardy

Drought Tolerance

Drought tolerant when established

Care & Maintenance

Care Guide

Grow Buddleja in full sun in any well-drained soil, including poor, dry, and chalky ground. Plants need little water once established and tolerate drought, though they flower more freely with occasional summer moisture. Shrubby species that flower on new wood are cut back hard in late winter to keep them compact and to promote strong flowering stems. Most are hardy in USDA zones 5 to 9, with top growth sometimes killed by hard frost and regrowing from the base. Removing spent flower heads before they seed limits the heavy self-seeding that makes B. davidii invasive in some regions. The shrubs are short-lived and can become woody and sparse without regular hard pruning.

Pruning

Species that flower on the current season's growth, including B. davidii, are cut back to a low framework in late winter or early spring. Spring-flowering species such as B. globosa are pruned lightly after flowering instead, as they bloom on old wood. Removing faded panicles through summer reduces seeding and can prompt further flowers.