Grass trees grow very slowly, approximately 1 cm per year.  A plant,
which is harvested from its natural habitat at a height of 2 metres, can
be anywhere between 100 to 200 years old, depending on prevailing conditions
and climate.  Grass trees form part of Australia’s hard-leaved,
fire adapted vegetation and occur mainly on soils which are very free draining,
and consequently low in nutrients.  They have a wide and relatively
shallow root system, about 600 mm deep and up to about a metre wide.  

Cultivation

• Choose a plant which has healthy, dark green foliage and select your
  planting site carefully. Tie the leaves of the plant into a bunch using
  soft cord before transporting or planting as the end of each leaf is quite
  sharp and you will find it much easier to deal with the plant if the leaves
  are confined.
• Grass trees need to be in full sun.  They require very free draining
  soil and an open position with good air circulation.  If you can’t
  provide these conditions in the garden, then it may be best to transplant
  the grass tree into a suitable container.
• If planting into the ground, the planting hole must be prepared before
  you remove the grass tree from the container.  The hole should be wider,
  and deeper than the container, this will allow room to incorporate a mixture
  of coarse sand, gravel and some of the existing soil below and around the
  root ball of the plant.  The grass tree should be planted at the same
  depth as it was in the container.
• If the planting area does not have good drainage it will be necessary to
  raise the bed by about 50cm.
• Do NOT tease out the roots when the plant is removed from its container.  It
  is important that the roots are disturbed as little as possible.
• Do NOT put any fertiliser in the planting hole, or around the plant.
• If planting into a container, use a good quality, free draining mix, such
  as ‘native’ potting mix.  The container should be quite
  wide and will need to be up, off the ground, on pot feet or bricks, so that
  the drainage holes in the pot remain clear.  You may also need to drill
  extra drainage holes in the pot.
• Water in well after planting to remove any air pockets in the soil,
  and apply ‘Seasol’ at
  the recommended rate.  ‘Seasol’ is a liquid plant tonic
  which encourages root growth. Continue to apply ‘Seasol’ at
  2 weekly intervals for a couple of months.
• The plant will require small amounts of water frequently for about the
  first month after planting.  After the first month, watering should be reduced
  to about once a week during the warmer months. 
• It is not really necessary to fertilise grass trees but if you wish to
  do so, then once a year is sufficient, using a fertiliser for native plants.

Grass trees can be rejuvenated by fire, but this can only be done every
5 years as this process consumes the stored reserves of the plant.  After
burning a plant may take between 3 to 6 months to develop new foliage.  Grass
trees sometimes appear to flower after a fire but this is not always the
case.  Each species of grass tree will flower only at a particular
time of year, and only if they have sufficient stored reserves to do so. 
Grass trees also flower as a reaction to stress.

Pests & Diseases

Phytophthora cinnamoni – this is a fungal disease which causes root
rot.  Usually present in damp or poorly drained areas.  Grass
trees are quite susceptible to this problem.
Scale on foliage – treat with pest oil or white oil when conditions
are cool.

Ann Costelloe