New Zealand Christmas Bush Metrosideros thomasii

Metrosideros thomasii is one of the compact small leaved forms, building into a dense, rounded evergreen small tree with a naturally tidy outline and very little bare stem. The leaves are dark above with a pale felted underside that shows when the wind turns them over. Summer brings heads of crimson stamens, which is what separates a true Metrosideros from the NSW Christmas bush, a Ceratopetalum that colours through its bracts instead. It gets used for coastal screens, clipped hedges and standards in courtyards.

Coastal exposure it shrugs off, and the cold it does not

Salt wind, sea spray and sandy ground suit it, and it holds dense growth on a front row boundary where softer hedging plants scorch. Full sun brings the heaviest flowering. Soil has to drain, so on clay plant into a raised, mounded row rather than a hole that collects water. For a screen or hedge, set plants roughly 60 to 80 cm apart and let them close before you start shaping a face. The limit on this plant is cold. Young stock is knocked about by hard frost, and a cold winter on wet heavy ground is what takes out newly planted rows in inland and highland gardens, where the plants brown off at the tips and never quite recover. Within a few kilometres of the coast this rarely comes up. Further inland, plant in spring rather than autumn, shelter the first two winters from frost and cold wind, and hold off the water through the cold months so the roots are not sitting wet while growth has stopped. Growth is moderate, so a clipped hedge takes time to fill, which is the argument for buying larger stock where a job has a deadline.

Boundary screen or courtyard ball

The other Metrosideros in this range, Little Dugald, is a compact shrub built for pots, low hedges and small courtyards. Thomasii is the larger framework plant: it carries a screen at boundary height, trains into a standard with a clean stem, and is stocked in advanced grades where a job needs structure from day one. Choose Little Dugald if you are working below window height or in containers, and thomasii if you need a hedge you can look up at, a windbreak on a coastal block, or a formal row of clipped specimens. The two do not mix in a single run: planted along one hedge line they clip at different heights and the face never resolves, so settle the finished height before you order.

Clipping without inviting rust

Clip once the summer flowering finishes, staying in leafy wood, since cuts made deep into bare old stems reshoot slowly and unevenly. In humid coastal districts, time the trim so the new flush hardens off before the muggiest part of the year, because myrtle rust takes hold on soft young Myrtaceae growth, and bin the clippings rather than composting them. Feeding is straightforward here, with no phosphorus restriction: a complete slow release fertiliser in spring is enough for a hedge, with a second application after clipping if growth is slow. Plants grown as standards need the stem rubbed clear of shoots two or three times a year to hold a clean trunk.

Choosing a size

This plant is available in 4 sizes, from 300mm up to 500mm, priced from $109.00 to $719.00 per plant. The size shown is the pot the plant arrives in, which is the rootball, not the height of the plant. Every size here is established stock rather than a starter plant, so this line is intended for immediate effect rather than for growing on. Not sure which to choose? Read our guide to fast growing screening plants.