Saturday, 16 September 2017

Growing Arisaema from Seed

Growing Arisaema From Seed 


Some species need no preparation, those that do will be noted below. The hard coated seeds often contain a germination inhibitor and this will need to be removed before germination will occur.  The simplest way to do this is by soaking and regularly changing the water.  The soaking period should be at least 48 hours with 6 changes.  With the final change, clean the seed completely by placing in a seive and then spraying with warm water for 10 minutes.  This is best done using a hand sprayer with a fine mist setting and spraying the seeds for 10 minutes with warm water.


Sow in a moist compost, covering the seeds with an equal depth of compost to match the width of seed - this generally means sowing on the surface and then covering with grit, sand or vermiculite (or a mix of all three).  It is entirely possible to use the same sowing mix to cover, I just prefer to use the mix grit/sand and a mica based medium to give a bit more control over emerging seedlings (plus it discourages surface diseases on the soil).

Depending on the species, germination may take a few weeks to several months.  What ever the species, never give up unless you are absolutely certain the seed has rotted away or otherwise lost.  Germination, especially in the more erratic species, may still occur a year after sowing - the seeds will grow when they are ready, this does not mean you have bad seeds or seeds that are not fresh - it is just natures way of ensuring conditions are correct for the crop of seedlings to emerge.

An alternative method, which allows several species to be kept together in a small space involves the following:

Get a damp paper towel - it should not be dyed and ideally not made from bleached paper
Place the seed evenly across the centre strip of the surface and fold in the edges to seal (you fold it twice efectively)
Place the folded towel in a ziploc bag and then place at the germination temperature.
Inspect the seeds weekly and any that show signs of sprouting treat as per growing on.
This way, more control is had and any 'bad' seeds can be removed before they spoil the batch.

Growing on.

The seeds will produce a leaf - just one.  It is this leaf that provides the energy that gets stored in the growing rhizome.  Keep this going as long as you can, feed it with a balanced feed in order to assist it in the early years.  Use this at 1/4 - 1/3 strength (so as not to scorch the roots and set the plant back).  Once it enters dormancy, overwinter cool and reasonably dry - they don't like being wet over the winter.  You can take this chance (dormancy) to re-pot your plant and inspect the rhizome (size and health checks).  Re-pot using a rich mixture containing a good deal of organic material and coarse material such as grit or vermiculite/perlite to open up the structure.

In subsequent years (pot growing), bring into growth in Spring and in later years, the flowers will be produced (often before the leaf).  The flowers last a week or so, sometimes longer and are followed by berries that turn orange, red or purple (species dependent).  For open grown plants, plant in a cool moist soil in the late Spring of the second or third year (when the rhizome is of a viable size and it is just coming into growth (it will be obvious).

Species                   Prep       Germination Strategy

A concinnum         Soak        Germinate Intermediate (15 - 18 C)
A consanguinem    Soak        Germinate Cool (10 C or less)
A costatum             Soak       Cold Stratify (4 Deg C - 8 - 12 weeks) Germinate Warm (21 C)
A flavum                Soak       Cold Stratify (4 Deg C - 8 - 12 weeks) Germinate Intermediate (15-18C)
A intermedium       Soak       Cold Stratify (4 Deg C - 8 - 12 weeks) Germinate Intermediate (15-18C)
A nepenthoides      Soak       Germinate Warm (21 C)
A speciosum          None       Germinate Intermediate (15-18 C)
A tortuosum           Soak       Germinate Warm (21 C)

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