Blooming Crinum natans

The aquatic plants of the genus Crinum have interested me ever since seeing them in the wild in Cameroon and Gabon.  These aquatic onions have a reputation in the hobby of being difficult and slow growing.  While I agree with slow growing, I do nto think that they are all that hard to work with.  Probably the biggest detractor is their size.  Very few species are available in the hobby, and all of them can grow to large for most aquariums.  The most common varieties (from west Africa) are C. calamistratum and C. natans.  The former is a smaller plant with very narrow leaves… almost like wrinkled strings.  C. natans can grow into a real monster.  I have several of both, and the individual in this video I have had around my fish room since 2008.

The aquarium in the video is a 75-gallon aquarium that I started in June, 2010.  I used a very nutrient rich layered soil substrate, which I credit for the incredible growth of this crinum.  The plant dominates the tank with huge leaves that fill the space from pane to pane.  Around our house we have nicknamed it ‘The Kraken’.  The aquarium is lit by four 48″ HO T5 tubes (2 x 6700K and 2 x 10,000K) for 10 hours a day.  The tank holds a LOT of plants, so I fertilize with an all-purpose liquid fertilizer every other day.  I also supplement the heavy root feeders (like The Kraken) with commercial potted plant food sticks (one every 3-4 months).  CO2 is provided by a yeast bottle, and the aquarium gets a 50% water change each week.  There is not heater in the tank, and in the summer the temperature averages 76-78 F, and in the Winter that average drops to 70-72.

Other plants include crypts (wendtii, becketii, blassii, pontederifolia, balansae), Aponogeton ‘lace’, Nypheaea lilies, jungle val and a large red rubin sword plant.  The only fish in the tank are a colony of Skiffia bilineata and a few Sycidium sp. gobies (for algae control).

The blooming of the crinum started on July 21, 2012.  I have never seen a crinum bloom inside before.  I do not really know if this is much of an accomplishment or not, but I am certainly enjoying it!  I am going to try to pollinate the blooms, but I am not sure if they will self-pollinate or not.  Hopefully I will have another video soon of the seed pods and seed germination….

6 Replies to “Blooming Crinum natans”

    1. It is a little fragrant, but you have to stick your nose into it to smell it. The second blossom opened yesterday, and the first is losing its rigidity today. I tried cross pollinating both blooms with each other. We’ll see….

  1. Dear Ted,
    I am having trouble getting my 3 aquatic onions to grow (2 natans, 1 calamistratum)…they are a light green color and one has lost its leaves…I have small rock gravel, 2 HO t5 (10, 000k each) about 18 inch from substrate, no co2 supplement, about 5 fish, and give micro nutrients once a month in liquid form. Also, filtration is excellent. Any advice?

    1. Hi Nick,

      I can think of two things to consider. First, Crinum are heavy root-feeding plants, so try a root tab or other root zone fertilizer that you can slip directly under the plants. Second, 10,000K is not the best color temperature for plants. Replace one of the tubes with a 6500 K tube, and the plants will photosynthesize better.


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