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Some observations on Blandfordia (Christmas Bells)

Florence Treverrow

I have been trying to grow Blandfordia grandiflora commercially for the last 12 years and along the way I have made a detailed study of thousands of different plants. This article briefly outlines my observations and conclusions to date.

The problem with try to grow and understand Blandfordia is that they are adapted for survival and therefore behave in unpredictable ways in cultivation. As with other species, this survival depends first on individual survival and second on species survival.

Illustration of Blandfordia grandiflora by Edward Minchen (1862-1913) From: 'The Flowering Plants and Ferns of New South Wales - Part 5' (1896) by J H Maiden, NSW Government Printing Office (Published as: Blandfordia flammea. From Australian National Botanic Gardens

In the wild Blandfordia live in a very harsh environment in poor soils that are deficient in most nutrients. They are poor competitors and it is known that they only flower well after a fire. The main effect of fire is probably to reduce competition and to recycle nutrients. It therefore seems likely that their survival strategy is firstly to wait out the bad times and be ready to take maximum advantage when conditions improve.

Blandfordia usually take at least 3 years to flower from seed, although some may take less. After flowering the plant dies off and is replaced by a new plant that grows between the leaves, from the corm, mostly at the time of flowering. The new plants then take one or more years to mature. The time to maturity of secondary plants is not related to the initial time to flower. To save confusion from now on I will refer to the initial and following plants that originally derive from a single seed as a clone.

In cultivation, a clone may appear to flower every year. This is sometimes because new plants take only a year to mature, and sometimes because some clones have plants of different ages at any one time. For example, if the plants of a clone take two years to flower, one plant flowers and produces a new plant at the time the other plant is one year old. If plants take more than a year to mature and the clone only produces one new plant each time then the clone is only able to flower every second year. At the other extreme are clones that produce 2 or more plants with each flowering and each of these plants takes a year, or less, to mature.

My observations have led me to conclude that flower initiation in most plants takes place in late summer to early autumn, possibly due to decreasing daylength. If conditions are favourable (i.e. sufficient nutrients and water are available), the flower spikes start to develop in late winter to early spring, probably in a response to increasing day length. The length of this developmental stage may be affected by temperature, but at least in cultivation, the time of flowering of a clone is about the same each year.

Some clones have 2 distinct flowering times and it appears that this is often because 2 spikes are initiated together in the same plant but start developing at different times. Some clones sometimes have the ability to initiate and develop their flower spikes as soon as the plant reaches a larger enough size, and this is why some flowers will be seen at almost any time of the year.

My conclusions about flower initiation are contrary to an earlier study which suggested that flower initiation occurs in spring and that it is necessary to have 500 hours below 10 degrees (i.e. chilling requirement) for initiation to occur. However, in the 10 years that I have been observing Blandfordia (since my first plants flowered) I have found no evidence to support this view.

It takes about 6 weeks for the spike to grow from the time it is visible in the centre of the plant to the time the first flower opens irrespective of spike height or other spike characteristics. After flowering, a lot of seed is produced (up to about 170 in a seed pod) and it takes about 6 weeks for the seed to mature. The time taken for these stages seems to be largely unaffected by environmental factors except for very late flowers.

Seeds germinate readily if there is enough moisture and plants are gradually pulled down by contractile roots, thereby protecting the growing point, whether it be vegetative or reproductive, from adverse conditions. In the couple of years following a fire other kinds of plants gradually take over and Blandfordia revert to a state of semi dormancy and wait for their next opportunity to grow and flower.

Clones in the wild may have corms over 30cm long and, given that even in cultivation (with much better conditions) corms grow very slowly, it seems reasonable to assume that clones in the wild may be a hundred years old (or more) and in that time may have only flowered 10 to 15 times.

Blandfordia grandiflora Click for a larger image

The second survival strategy of Blandfordia is the huge diversity of forms. No two clones of Blandfordia are exactly the same. There are layers of complexity built into every one. For every feature of the flower, the flower spike and the plant there is diversity and these are all influenced to some extent by the environment. For example, the maximum height of the flower spike for a given clone is fixed by its genetic makeup at between 30cm and 145cm but this height will only be reached if environmental factors such as nutrition and water availability are at an optimum for that particular clone.

Flower colour

This is determined by

1. base yellow (4 shades)
2. overlying red or orange colour about 4 or 5 shades)
3. how far down the bell the overlying colour goes

and the intensity and pattern of the overlying colour.

People often say that all Christmas bells are beautiful but when you have seen as many as I have you realise that this is not so.

Some colour combinations are absolutely stunning and sometimes the flowers even appear to be luminescent. Most colour combinations are good, but when a light shade overlies one of the darker shades, especially with stripes, the result is not very appealing at all.

Flower shape

Although most flowers do have a bell shape, flower shape can vary from long and thin (like a fuschia) to short and fat (like a poppy).

Flower number

Most spikes have between 4 and 25 flowers. Sometimes there may be less than this and one clone once had a plant with 34 flowers.

So, as you can see, some progress has been made in understanding and cultivating Australia;s best wildflower over the last 12 years but there is still a long way to go.

From the newsletter of Far North Coast Group of the Australian Plants Society, New South Wales, June/July 2000.

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Australian Plants online - December 2002
Association of Societies for Growing Australian Plants