Buddleia

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Botanical Name

Buddleja davidii

Family

Buddlejaceae (buddleia)

Also known as

Butterfly bush

Where is it originally from?

China

What does it look like?

Deciduous (occasionally semi-evergreen) open, multi-stemmed shrub (<3+ m tall). Stems are bluntly angled, clad in tufts of easily-removed soft woolly hair (downy hairs when young), and become lax when long. Thin, willow-shaped leaves (6-20 x 3-8 cm) are usually hairless above, white or hairy grey underneath, and finely toothed. Distinctive, dense, cone-shaped hanging clusters (30 x 5 cm) made up of many fragrant purple or white flowers (5 mm diameter, Dec-Feb) with orange insides are followed by seed capsules (5-10 mm long).

Are there any similar species?

Several pink and mauve hybrids and cultivars are also sold.

Why is it weedy?

Establishes and grows quickly, and forms self-replacing thickets. Extremely ecologically versatile, tolerating a wide range of (especially poor) soils, hot to cold (likes frost), wet to moderately dry conditions, deep shade or open areas, damage, and wind.

How does it spread?

Seed is spread by wind and water, soil movement, and dumped vegetation. Plantation forest, wasteland, roadsides, gardens and parks are all sources of infestation.

What damage does it do?

Forms dense stands in wide range of habitats. In riverbeds it can alter water flow, causing silt buildup and flooding.

Which habitats is it likely to invade?

River beds, streamsides, disturbed forest and shrubland and margins, short tussockland, pumice, lava, and stony and bare land. Major pest, often only exotic species found in forests in mountain regions.

What can I do to get rid of it?

1. Physical removal - dig out small plants or excavate larger areas. Dispose or burn all plant material.

2. Cut and paste - Cut the stem/trunk as close to the ground as possible and cover the entire stump with herbicide as soon as possible after cutting.
Apply glyphosate gel (120g/L strength)
OR When a gel is inadequate apply commercial formulations (120g triclopyr/l of oil or product containing triclopyr and picloram 50ml/L water mix). Apply the mixture over the entire exposed surface of the cut stump, i.e. top and sides.

3. Basal spray - spray stems up to 20cm diametre with X-Tree Basal. Ensure the base is thoroughly covered at ground level.

4. Drill or frill - Drill downward sloping holes around the circumference of the trunk about 8-10 cm apart, or Frill (make deep cuts into the sapwood at regular intervals around the base of the tree, taking care not to ring-bark the plant). Fill the holes with undiluted 'neat' glyphosate (360g/L active ingredient) or saturate the frill cuts with glyphosate (360g/L active ingredient) mixed at 250ml/L

5. Foliar spray - Apply herbicide using a hand held sprayer/knapsack to plants <1m tall or gun and hose for larger infestations. Use the label recommended adjuvant.
Apply metsulfuron herbicide (600g/kg active ingredient at 5g/10L knapsack or 20g/100L gun and hose) plus organosilicone penetrant (3ml/L) Note: Metsulfuron overspray will kill other (desirable) broadleaf plants and has residual activity in the soil which aids in killing below ground parts.
OR picloram/triclopyr herbicide (picloram 100g/l and triclopyr 300g/l active ingredient at 6ml/L) plus organosilicone penetrant (1ml/L) to thoroughly wet all parts of plant. Note: Triclopyr and picloram herbicides are 'grass friendly' but overspray will kill other (desirable) broadleaf plants. Picloram has residual activity in the soil which may leach and kill other plants. Do not use under and around other (desirable) broadleaf plants.

6. Biocontrol - For further information regarding the buddleia leaf weevil please visit: https://www.landcareresearch.co.nz/discover-our-research/managing-invasive-species/weed-biocontrol/projects-agents/biocontrol-agents/buddleia-leaf-weevil

CAUTION: When using any herbicide or pesticide, PLEASE READ THE LABEL THOROUGHLY to ensure that all instructions and directions for the purchase, use and storage of the product, are followed and adhered to.