Dicksonia antarctica - Soft Tree Fern, Man Fern, Tasmanian Tree Fern
Dicksonia antarctica is part of the family Dicksoniaceae. Members
of this family are the tree ferns. They are terrestrial ferns and have an erect
rhizome forming a trunk, large spreading fronds and are very hairy at the bas
of the stipe. There are only one genera and three species in Australia
with D. antarctica being the largest.
D. antarctica is wide-spread species growing from south-eastern Queensland, through the NSW and Victoria coast and in Tasmania. This species is endemic to Australia. In the wild this species likes to live in moist areas with high water content in wet sclerophyll forests, along creek beds, in gullies and occasionally at high altitudes in cloud forests. [1]
Dicksonia antarctica has many advantages over almost all the other tree fern species. It is nearly hardy in cool temperate climates. It is incredibly easy to grow. It is able to live through being shipped from Australia to Europe, which takes seven weeks in a container. Most remarkable of all, it can survive being saw off at ground level as a mature tree up to 6m (20 feet) in height. The severed plant has no roots apart from those an the trunk. When, in due course, the trunk in planted on the other side of the world, it produces new fronds in 4-6 weeks and with a year has rooted into its new growing medium. The survival rate is estimated to be 99% and the failures were down to mistakes by the growers. [2]
The condition D. antarctica thrives in is in filtered
sunlight, loose well drained soils with lots of organic matter and lots of
water. However, this species can still withstand some drying out and can
survive in drier conditions.
D. antarctica is relatively easy to grow, the most important thing is to keep it
moist and the base covered with mulch to keep it moist and supplied with
nutrients. It is a valuable species in the garden as it can be used as a host
for epiphyte ferns, orchids and bryophytes. It also provides shelter for more
delicate fern species to flourish underneath. Other benefits of this species is
that the mature specimens can be easily transplanted and it can be grown both
in and out of doors.
Also, it can be used as a food source with the pith of the plant being eaten either cooked or raw and is a very good source of starch. [1]
Description: Dicksonia antarctica is probably the best known of all the
treeferns.
Dicksonia antarctica can grow to 15 m in height, but more typically grow
to about 4.5-5 m. The large, dark green, roughly-textured fronds spread in a
canopy of 2-6 m in diameter.
They can be cut down and, if they are kept moist, the top portions can
be replanted and will form new roots. The fern grows at 3.5 to 5 cm per year
and produces spores at the age of about 20 years.
The plant can grow in acid, neutral and alkaline soils. It can grow in
semi-shade. It strongly resents drought or dryness at the roots, but does best
in moist soil.
In winter protect the crown by wrapping it up with straw or dead fronds. [2]
Gardening: Dicksonia antarctica is hardy to zone 8 and it will thrive
outdoors only protected or it have to be kept in a conservatory all year round.
This tree fern must be watered abundantly in hot weather during the growing
period. They also need water from time to time, especially if the conservatory
is heated. The outdoors specimens plunged in pots into the garden from spring
to autumn and then moved inside into a protected environment for winter. This
is especially important for smaller tree ferns, around 60cm (2 feet) which are
less hardy than taller, older ones. Also they are lighter and not too difficult
to move around.
Larger tree ferns can be left out over winter but need protection in zone 8 or
colder. The ring of fronds at the top of the trunk forms a funnel that leads
down into the trunk very nearly as low as the meristem (the bud tissue in the
crown). This funnel will readily collect water. To prevent this from happening,
stuff it with straw to about 15cm (6 inch) above the top of the trunk. This
keeps the meristem warmer and excluded the worst of the winter wet, greatly
reducing the risk of a block of ice forming in the crown. In mild winter this
is sufficient protection for large plants of 1.2m (4 feet) or taller. For
shorter, younger tree ferns in addition to the straw should be wrapped in
insulating material around the top of the trunk. It can be used a belt of
polystyrene plant trays, tied together and cushioned from the trunk with more
straw – the straw is stuffed behind the trays and keep them secure. Tie a
circular piece of polystyrene over the crown, which helps divert rainwater away
from the meristem, offering protection against cold and keeping it dry. In
severe weather, further layers of insulation, perhaps sacking or straw bales,
can be tied around trunk. Other insulation materials could be garden fleece or
bubble wrap.
If the specimen is purchased as a log, soak the base of the trunk for a
few minutes prior planting. If it is to be planted out in the garden, select a
shady spot, protected by the wind; in less suitable conditions these tree fern
tends to produce shorter fronds. Plant the log so that as little as possible is
buried, while ensuring that it will not topple over – as these tree ferns are
priced according to the length of the trunk.. Once the trunk is firmly in
position, water it copiously all over and around the trunk. It is not
recommended to fill the crown with water, especially if the weather is cold and
damp as this practice could encourage rot. Keep the log watered daily if
possible until the new leaves have emerged and expanded. A well watered tree
fern produces larger fronds and generally will better set up for the next
season.
To grow a tree fern in a pot, plant the log as shallowly as possible.
Water copiously and within six months the log should rooted and become secure.
Use a pot as small as possible for the log at first. There are several reasons
for this: because the tree fern needs to be watered so much over the first few
months, the potting mixture inevitable become very wet and a smaller pot has a
better chance to dry out a little between waterings; the unrooted log if very
difficult to secure in a large pot unless it is planted unacceptably deep;
smaller plants are easier to move around and more economical on potting
mixture. After one full year in a small pot – the next spring – the tree fern produced
roots that will apear out of the drainage holes. When this happens it is time
to pot it on.
Feed the tree ferns only after roots are fully developed. If it is fed
too much nitrogen, there is a risk that a lot of foliage will be produced with
little or no root, possibly stressing the plant if it is allowed to dry out at
all. Feeding with a high potash and low nitrogen fertiliser to encourage root
growth may be fine but not necessary. [2]
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