Blue morning glory
Also known as
Blue dawn flower, blue bindweed, blue convolvulus, morning glory, Ipomoea learii, I. congesta
Where is it originally from?
Throughout tropical areas
What does it look like?
High climbing vine with tough, hairy, twining, running stems with tough fibrous roots without rhizomes. Leaves (5-18 x 5-16 cm) are usually 3-lobed and silky-hairy underneath. From late spring to early winter, groups of 3-12 deep blue-purple flowers that are pink at the base and wither in the midday sun are produced. Little or no seed is produced in New Zealand.
Are there any similar species?
Exotic species: Purple morning glory (I. purpurea), great bindweed (Calystegia silvatica), field bindweed (Convolvulus arvensis). Native species include: railway creeper (I. cairica, I. palmate), pink bindweed or convolvulus (Calystegia sepium), shore bindweed (Calystegia soldanella) and Calystegia tuguriorum.
Why is it weedy?
Very fast growth rate, longevity, dense smothering habit and ability to climb to top of high canopy makes this the dominant vine wherever it occurs. Tolerates hot to cool temperatures, and damp to dry conditions.
How does it spread?
Creeping stems spread this plant locally, and stem fragments are moved in dumped vegetation. Sources are gardens and wasteland.
What damage does it do?
Climbs over all other species, ultimately killing them. Can replace forest with low weedy blanket, and is the last species in many cases when a bush area totally succumbs to weeds.
Which habitats is it likely to invade?
Most warmer habitats except swamps and coastline.
What can I do to get rid of it?
Firstly establish that the species is not a valued native plant.
1. Hand pull, dig out roots (all year round). Dispose of roots and stems at a refuse transfer station or bury deeply.
2. Cut down and paint stump (all year round): glyphosate (100ml/L) or metsulfuron-methyl 600g/kg (1g/L).
3. Cut vines at waist height (summer-autumn) and spray foliage below: glyphosate (10ml/L + penetrant) or metsulfuron-methyl 600g/kg (2g/10L + penetrant (knapsack) or 20g/100L + penetrant (spraygun)). Follow up to check that slashed stems have not resprouted.
What can I do to stop it coming back?
Slashed stems resprout. Cut plant material can reprout. Eliminate from bush edges and dumps. Limited follow-up required.