Pungas & Fernery.

I have always loved the look of NZ native tree ferns. It is a plant that always reminds me of home here in New Zealand and its native bush. They give the bush here a Primordial sort of vibe of a time before humans roamed the earth. Tree ferns are colloquially known in New Zealand as “Pungas”. This appears to be an English corruption of “Ponga”, a Maori name specific to Cyathea dealbata (silver fern). The unfolding fronds of the tree fern are represented in the Koru, now pretty much a symbol of our country & its Maori heritage. Punga trunks are commonly seen for sale but are not actually Ponga but Wheki (Dicksonia squarrosa). These are often used to make fencing or for garden retaining walls and often have a reasonable chance of coming back to life. 

When we first planted out our garden, we have one area of the yard that is heavily shaded from our Fig Tree and the neighbouring property's fence. We decided that this would be an area perfect for our "Fernery". We had a vision of eventually having a "Punga Forest" of sorts that would remind us of the great stands of Punga & native Ferns that we see out on our hikes in the NZ bush.
Most (but not all) ferns are shade lovers so in general you need to avoid planting in a windy spot and in full sunlit areas. Pungas (aka Tree Ferns) are very much in this category and one thing i have learned during my Fernery experience is that Pungas either need to be planted in the shade or at the very least under the protecting shadow of a larger pioneer tree. The other important thing to keep in mind if that they love moist soil and loath drying out in Summer. To avoid them drying out, apply lots of mulch over the root system to conserve soil moisture in summer. The idea is to try to simulate the bush conditions in which tree ferns grow best, giving them moist soil and high humidity.

There are two main groups of tree ferns in New Zealand: Cyathea and Dicksonia. They are easily distinguished since Cyathea is scaly and Dicksonia is hairy. The most frequently seen species of tree fern in New Zealand are Cyathea dealbata (silver fern), C. medullaris (Mamaku or black tree fern), C. smithii (katote), and Dicksonia squarrosa (wheki).

In terms of NZ native tree ferns there are about 9 varieties, they fall into 2 distinct species -

1. Dicksoniaceae (Dicksonia for short) are distinctive due to long woody trunks and crown of fronds on the top. The two common varieties are:
Dicksonia Squarrosa (Whekī)
Dicksonia squarrosa is common throughout New Zealand, except in the coldest of habitats. It is particularly abundant around streams and other wet areas. Trunks of Dicksonia squarrosa often arise in close proximity, and the dead orange-brown fronds often give it a scruffy appearance. However, unlike D. fibrosa, D. squarrosa does not retain a skirt of dead fronds. The frond stalks of D. squarrosa are bristly-hairy, dark-brown, and comparatively long. Dicksonia squarrosa has buds on its trunk, and it can resprout if the main crown in damaged. Most “punga” trunks for sale are D. squarrosa. 

Dicksonia Fibrosa (Whekī-ponga)

D. fibrosa is a slow-growing plant which has a very thick, soft and fibrous rusty brown trunk. It holds on to its dead leaves producing a distinctive pale brown skirt, distinguishing it from the related Dicksonia squarrosa. D. fibrosa can reach a height of 6 metres (20 ft).

2. Cyatheaceae (Cyathea for short) - different from the Dicksonia due to long hairs on the trunks. The two common varieties are:
Medullaris (Mamaku or Black Tree Fern)
The mamaku is one of the world's largest tree ferns, sometimes reaching over 18 metres and with individual fronds up to 6 metres, making a huge feathery umbrella. Mamaku like lots of light and are not found in dense bush, but rather on the moist fringes of forests, river banks or in light gaps such as old slip sites or road cuttings.

Dealbata (Silver Fern or Ponga)
The silver tree fern is easily distinguished from the mamaku, by having a distinctive silvery white underside to its fronds. It does not grow as tall, rarely exceeding 8-9 m and with upright fronds, like a shuttlecock, up to about 3.5 m. Unlike mamaku, these ferns prefer some light shade and also grows in drier spots. If grown in an open situation its fronds can become ragged and untidy and neither species will do well, or look attractive in very windy sites.

Smithii (Kātote) 

It produces masses of very soft and delicate looking fronds which spread horizontally from the crown and reach 2 – 2.5m in length. The fronds rather than uncurling in the manner of most tree ferns, in which the main frond stalk unrolls almost to its full length before the "frondlets" (pinnae) unroll, the fronds tend to expand all at once up the length of the frond. The trunk is covered in chestnut coloured scales, and while it can reach up to 8m in height it is fairly slow growing. The old fronds hang down to form a skirt around the trunk, which helps protect it from pests and maintain some humidity.

Cunninghamii (Gully Tree Fern)

C. cunninghamii is an uncommon and slow-growing tree fern. It grows in damp forest, often emerging from stream gullies and riverbanks. The erect trunk may be 20 m tall and is usually 6-15 cm in diameter, occasionally as much as 20 cm. Fronds are tri- to tetrapinnate and 3 m or more in length. The branches are slender, black brown, warty and scaled. To do well in cultivation, C. cunninghamii needs a lot of moisture & shade. Rich humus is a good growing medium. Plants should be protected from the wind.

There are seven Cyathea species native to New Zealand. Five are endemic to New Zealand, with Cyathea cunninghamii also occurring in Australia and C. medullaris being recognised from several Pacific Islands. Two of the New Zealand species are confined to the subtropical Kermadec Islands: C. kermadecensis and C. milnei.