Cameron & Rhoda McMaster's

The germination habits of
Crinum campanulatum

By Cameron McMaster.

Crinum campanulatum is endemic to the Eastern Cape, occurring in widely scattered seasonal pans or vleis between Bathurst and East London and as far inland as Peddie. Its dependence upon seasonal standing water to flower means that the reproductive cycle of this crinum is opportunistic and is
completed only if and when sufficient rains fall to fill the vleis. During most of the summer and all winter, the vleis are dry and heavily grazed by livestock, and there is little visible trace of the plants. If sufficient rain falls to fill the vleis to a depth of 30 -50cm, the plants are protected against livestock, which are reluctant to enter the water, and within a few weeks successful flowering and seed production is achieved. The bulbs are rooted very deeply in the mud of the vleis - often 20cm and more deep. This affords them protection through the periods when the vleis are dry and also prevents them from being uprooted by grazing livestock.

Growth, flowering and seed production can occur any time when it rains during the summer.  We have collected seed at various times between November and July. When conditions are suitable, dense stands of flowers occur, making a spectacular display. Fresh flowers are mainly light pink, darkening to deep
carmine as they get older. Only in one vlei have we observed pure white plants. In this particular vlei there is a wide colour variation, from light to deep pink, with approximately 5% of the population being pure white. 
The white plants also tend to have green stems and fruit, in comparison with the normal plants which are red and purple.

As the fruit matures, the stems fall and float on the water. After some time the membranous seed capsules disintegrate and the seeds float. The seeds
remain dormant while floating in the water.  Apparently they will only
germinate when they dry off, which occurs as the water in the vlei evaporates and the seeds come to rest on the mud. We have observed that seeds
germinate almost immediately after being removed from the water. 

To test this  I did a simple trial with seed I collected near Peddie on 8 July this year. On 10 July I took a random sample of 20 seeds that had not started
germinating.  I placed ten in a glass of water and ten on a dry punnet.
Within four days 9 of the ten dry seeds had germinated and had roots up to 2 cm long. At this stage I removed the ten seeds that had remained floating in
water (with no sign of germination) and left them to dry. On 18 July, just four days later, they all started to germinate.  It is clear that while the seeds of
Crinum campanulatum remain wet, germination is inhibited, but is stimulated as soon as they dry. To delay germination after collecting seeds, keeping them wet is clearly a solution. Once they dry, germination and rapid development of the radicle is inevitable, even if kept in a fridge.

We have found
Crinum campanulatum very easy to germinate and grow, even in normal outdoor seedbeds. In cultivation it seems not to be necessary for the plants to be submerged in water to develop, and normal nursery or garden conditions are fine to produce bulbs.  In cultivation they tend to remain evergreen. We are not yet sure how long plants take to reach flowering size and if they will flower without the stimulation of submersion in water. Perhaps there are IBSA members who can enlighten me.

I do know that they make excellent water features and grow very well if planted in containers in a pond. I grew them successfully for many years in mud retained by bricks in my fish pool - the mud being kept just at water level.  I grew them together with
Cyrtanthus mackenii under these conditions - the bulbs of both species being continually below water level.  They both thrived and flowered well. In its natural habitat along the streams in coastal bush, C. mackenii grows like this at the waters edge with bulbs often permanently immersed.