Hawthorn
Crataegus monogyna
DESCRIPTION
Hawthorn was originally imported from Europe and used in NZ as a very popular hedge plant. As is usually the case with imports, hawthorn did so well in its adopted land that it became a problem invader.
It’s a deciduous shrub or tree, and can reach a height of 10 metres. It has many branches & stems, coloured red/brown when young and silver grey when mature. The branches are heavily adorned with very sharp thorns (spines) to 12mm in length.
Leaves are hairless and triangular, about 50mm x 45mm across, and have deep lobes. The hawthorn leaf is often attacked by slugs, and such damage is very commonly seen on hawthorn plants in NZ.
Flowers are usually white, occasionally pink, with 5 petals, and up to 15mm diameter individually. They grow in clusters containing 6-12 flowers, appearing October to November.
The fruit is bright red and shiny; looking somewhat like a cherry in shape and size, but not so dark red as a cherry. The fruit is eaten, and the stone inside subsequently spread, by birds. Fruit appears in late summer and early autumn.
Seen in all parts of NZ, hawthorn prefers roadsides, disturbed sites of old hedges and fences, deserted sites, burnt land, shrubland and forest margins, tussock land and cliffs.
Hawthorn is very tolerant of extreme and marginal conditions; dry or wet, hot or cool, shade, high wind, salt environments, and virtually all soil types.
MANUAL CONTROL
You can dig out smaller hawthorn at any time of year. The removed plants may be stacked and left to rot down on site.
HERBICIDES TO CONTROL HAWTHORN
Non-spraying Techniques, effective year-round:
Stump Swabbing Herbicides to Kill Hawthorn
- Cut stem right through and apply 5g/L of MSF600 liberally to the fresh-cut stump surface.
- Cut'n'Paste MetGel applied as a paste on the cut stems is a simple and effective control
- GrassMate XTRA 1 part GrassMate XTRA with 20 parts of water or diesel.
Cut & Squirt Weedkiller to Kill Hawthorn
Make cuts with a small axe or machete every 15cm around the trunk and squirt into each a dollop of thin paste made with MSF600 and water.
Injection Herbicides to Kill Hawthorn
Drill holes downwards at an angle into trunk, into the sapwood level, at 15cm intervals around the lower trunk. Using a drench gun or similar squirt a slurp of G-360 GLYPHOSATE – 300ml/L water or undiluted GrassMate, or a MSF600 slurry/paste into each hole.
Spraying Herbicides to Kill Hawthorn
Spray with MSF600 at 5g per 15L knapsack, or 35g/100L by handgun. Spray only during ideal growth conditions; Nov–Mar. Works best on bushes to 3M height. Thorough coverage of all foliage is essential. Use SuperWetter – 10ml/10L water to aid penetration.
