Saturday 23 May 2015

Alcantarea Propagation By Division.

 Alcantarea were once very expensive & almost unobtainable bromeliads only seen in the hands of a few enthusiasts. Thanks to tissue culture they can now be obtained with little difficulty at a reasonable price. Most are sizeable plants tolerant of sun and exposed conditions; they often rot if grown with too much shade & moisture. I like to use them instead of the common Agave attenuata that became popular around the turn of the century.

Alcantarea heloisae & extensa.
 
 
Alcantarea imperialis
 
 
Over the last decade I have managed to obtain 10 or so varieties of these plants, flowering 4 types. As with virtually all bromeliads, plants die from the flowering growth and commence new shoot production at the base, forming large offsets or pups:-
 
 
This is one of 3 large pups removed from the Alc. extensa plant pictured flowering in the first photo around 2 years from blooming, ready for potting. It  has been quite happily sitting upright wedged between other plants for around 8 months.
 This Alc. heloisae pup was potted last autumn & is well on its way to maturity:-
 
 
One unusual characteristic of this group of bromeliads is their ability to produce small offsets from the base of the plant before maturity, commonly called grass pups. Here is an example of this type of growth on an Alc. imperialis rubra:-
 
 
Grass pups can be carefully removed from the parent plant provided a section of the parent plants' stem is taken at the same time. Large pups are easiest to remove; they are more fully formed as plants in their own right, with little attachment to the parent. Some growers slide a fork between the pup & parent before cutting to aid in removal. I find waiting for the grass pup clusters to grow in size gives the best result, rather than removing at a smaller size.
 
 
The plant pictured above after pup removal.
Note the section of stem removed. Small pups left behind can be seen at the base of the wound & to the right, green in colour, along with a reddish pup that received more light. These will be left to grow larger before separation.
The removed growths are shown below:-
 
 
The top row consists of pups taken from the front of the stem; note that the bases are intact giving a good chance of root production & growth. The lower row of pups were taken from the right side & have been cut through; they should have been left longer on the plant to increase in size. Such plants can be left to seal over & planted on their side; tiny new growths often form at the base of the cut that can then grow on, preventing waste of propagation material. In this case they were discarded as plenty of pups were available, but highlights the importance of being patient!
 
Smaller pups are best potted as groups:-
 
 
Here are two group plantings after removal of larger pups for potting as single plants in 200mm pots (see below).
 
 
Grass pups can even form on plants at this growth stage:-
 
 
This is the base of one of the plants in the back row of the above group.
 
Larger plants that rot in the centre will also proliferate in pups as growth is directed into the plants' basal eyes, such as with this Alc. glaziouana:-
 
 
These can be removed & potted singly or as a group.
 
Happy Gardening!
Russell.