Hippeastrelia: A Guide to Growing the "Impossible" Bulb

Oct 2, 2011
Peter Ashby

Hippeastrelia "Durga Pradhan" - Peter Ashby

Once thought of as an impossible hybrid to create, this stunning cross between Hippeastrum and Sprekelia is a garden flower sure to please.

The Scarlet Show-stopper

The hybrid bulb Hippeastrelia is one of those flowers that has the power to stop you in your tracks at first sight. In the height of Summer, bulb enthusiasts wait with anticipation as the sturdy flowering stems rapidly lengthen and the paired buds expand and flush deep red. Suddenly the petals flare wide, recurving into a shallow sculpted trumpet up to 14 cm across, asymmetrical but elegant. These incandescent blooms are perfectly complemented by long stamens loaded with pale gold pollen, and fountains of arching glossy foliage.

Unlikely origins of Hippeastrelia

This dazzling child is the progeny of two New World amaryllids, or plants that belong to the huge family Amaryllidaceae which also includes such familiar garden bulbs as the daffodils and snowdrops. The first parent is a red hippeastrum, one of a genus widely distributed throughout South America but best known for the showy hybrids often sold in boxes and given as presents at Christmas. These come in a great variety of reds, pinks, white, peach and bicolour types and are frequently though incorrectly known as Amaryllis.

The other parent is Sprekelia formossissima, the Aztec or Jacobean lily from Mexico. The genus Sprekelia was at one time thought to contain just two or three species but there may be others in Peru and elsewhere and futher research is required. The Aztec lily produces single, short-lived flowers but these are deep red with curled upper petals and the lower part of the bloom sweeps down to create a "lip". The result is so exotic that some growers have likened it to an orchid.

Crosses between Hippeastrum and Sprekelia have been made many times over the past few decades, but at one time standard horticultural thinking dictated that such a hybrid was impossible. We owe the very first one to the enterprising spirit of an Indian schoolboy, Udai Pradhan, who decided to prove the establishment wrong.

Today he is a celebrated plantsman and expert on Himalayan flora, but in the 1960s, while still at school, he decided to see what would happen if he crossed Sprekelia formossissima with a red hippeastrum (the identity of which is unfortunately unknown). The resulting offspring flowered when Udai was 13 years old and he named the plant in memory of his grandfather, a reknowned nurseryman. Hippeastrelia "Durga Pradhan" is still the best known hybrid but a browse through the listings of bulb merchants will reveal others such as "Red Beauty", "Mystique" and "Red Star".

The best of both worlds

All of the most popular crosses combine the characteristics of their parents in an elegant synthesis that is sometimes lacking in other plant hybrids. The glossy leaves are broader than those of Sprekelia but firmer and less easily damaged than the foliage of hybrid hippeastrums. The flower stems are shorter than Hippeastrum but carry two blooms instead of the single flower of Sprekelia. In form, the flowers have much broader petals than Sprekelia but have retained its unusual conformation.

Cultivating Hippeastrelia

Growing Hippeastrelia is simplicity itself. It is said to be hardier than its parents and in warmer areas with marginal frost it can be grown outside in a well-drained, sunny location where the bulbs can be protected in Winter if necessary. It is as a container plant that Hippeastrelia excels, however. One bulb normally produces offsets so prolifically that the expanding colony can easily deform or even break through the sides of a pot.

Nothwithstanding, container cultivation means that it can be moved to a suitable location indoors or out when in flower and brought into a greenhouse or conservatory during the winter. Hippeastrelia is remarkably unfussy regarding compost and is equally happy in a medium based on loam such as John Innes No. 3, or a compost with higher organic content to which some horticultural grit or sand has been added to improve drainage.

The rounded bulbs have a dark tunic and should be planted with the top of the neck barely visible. It is best to plant only one bulb in a 20 cm pot, transferring the plant into progressively larger containers as necessary. The plants are tolerant of high summer temperatures and light levels but must not be left in direct sun for long periods or the handsome foliage will scorch. It is better to use plastic pots in warm climates as clay pots are prone to drying out rapidly, and never use black containers as these absorb the heat instantly and will quickly burn succulent roots.

Given plenty of water and a weekly feed with general purpose liquid fertilizer, Hippeastrelia can flower more than once in a season. It frequently stays evergreen throughout winter, when the water can be reduced and feeding limited to perhaps once a month.

The next generation

As with many other bulbous plants, Hippeastrelia can be propagated by removing offsets from the parent bulbs. This is not always an easy task because after several years of healthy growth, offsets of different ages can be very tightly packed together. Eventually you will have to separate them out of sheer necessity to ensure the vigour of your plants.

If you are patient, growing from seed has the potential to bear some very interesting fruit. Hippeastrelia is usually self-fertile and there is a good chance that the F2 or second generation plants will differ from the parent. You can transfer the abundant pollen to the stigma with your fingertip: all being well, this should result in a three-chambered seed capsule that will ripen and split open 4 to 6 weeks after flowering. The flat black seeds are best sown within a few weeks, although if stored under cool conditions they remain viable for several months.

Sow the seeds thinly in pots of sterile seed compost rather than trays, and cover the seeds with no more than 5 mm of medium. Alternatively, float the seeds on the surface of a glass of water and plant them individually when you see the first root emerging. Whatever method you choose, maintain them between 22-24º C for optimum results.

Eventually you will have to separate and transplant the young plants into individual pots. They grow rapidly, but you are going to have a wait of up to seven years before the first flowers appear. Will it have been worthwhile? You will not know until the day your plant unfolds its first buds, but the satisfaction of nurturing Hippeastrelia and other bulbs from seed to maturity surely has to be one of the great joys of gardening.