Regenerating shrublands and open scrub provide good habitat for many orchids. Spring and summer is the time to find many in flower on dry clay banks, especially the sun orchids (Thelymitra species), Petalochilus species, and the horned orchid (Orthoceras novae-zeelandiae).
Pterostylis tasmanica, a rare species found in a few scattered places from the Far North to Wellington, is also in flower during spring. Aporostylis bifolia, with two unequal-sized leaves, enjoys a damp habitat in high altitude scrub and sends up a stem bearing a small white flower in summer.
Acianthus sinclairii, a gnat orchid with heart-shaped leaves, flowers in winter, as does the common spider orchid Nematoceras trilobum.
Many orchids flourish beside lakes and streams, and in swamps, bogs and damp grasslands. Pink-flowered Spiranthes novae-zelandiae is found in wet dunes as well as damp alpine grasslands. It is New Zealand’s only spiral orchid, a group more common in the northern hemisphere, where they are known as ladies’ tresses.
Thelymitra cyanea, a swamp-dwelling sun orchid, produces vivid blue flowers with dark stripes each summer. Waireia stenopetala is an alpine orchid, favouring wet scrub and bogs. Its leathery hood is large enough to cover and protect the delicate flower parts against the elements.
A few orchids have a tenuous hold in New Zealand, growing in a single colony, or a few scattered sites. Because they are common in Australia, it is likely that they are recent arrivals in New Zealand: their seeds would have been blown across the Tasman Sea or carried by migrating birds. Among them are:
- Paracaleana minor, a small flying duck orchid that does not do well in New Zealand, and now survives in a single colony by a Rotorua hot spring.
- Cryptostylis subulata, a recent Australian arrival, which has survived and even flourished in Northland swamps because its Australian wasp pollinator arrived with it.
- Calochilus paludosus, a swamp orchid rare in New Zealand, but widely scattered. Known as a beardie, its lower petal (lip) is covered in colourful hairy growths.