5 tips for out-growing gorse

Gorse plants live for around 30 years and reach a maximum height of 5m; a native such as kānuka can live for more than 70 years, reaching 16m. Gorse seeds can't germinate in shade, so if you're patient, eventually the natives win.

That's backed up by research. One study found gorse was vigorous in 10-year-old scrub (eg, mānuka, kānuka), senile in 34-year-old scrub, and dead in 40-year-old scrub.

Other studies have found:

• Native tree seedlings have a higher survival rate in gorse than in kanuka stands, probably because of openings in the canopy and the lower density of hares and rabbits.

• Woody native trees establish best when gorse is low in density, with a shallow litter layer underneath (mostly gorse stands over 25 years old). They're far less likely to establish in gorse plots younger than 25 years, probably because it has a coarse-textured, deep, slow-to-decompose, dry litter layer than older gorse.

• If you use seed ‘bombs' to help establish natives, the best seeds to use are larger ones which more easily germinate under shade than ones with tiny seeds. Options will depend on where you are in NZ, but include karaka, taraire, and pūriri.

• Once gorse starts to be shaded out (70% light or less), its growth rate falls significantly.

Read more: how to make seed bombs thisnzlife.co.nz