Plant of the Month September 2006

Begonia rex hybrids

Begonias belong to the Begoniaceae family which consists of an enormous range of tropical  and sub-tropical species. Begonias are botanically divided into three basic groups such as rhizomes, tubers and fibrous-rooted types.  This enormous genus is further grouped as Cane-stemmed, Rex-cultorum, Rhizomatous, Semperflorens, Shrub-like, Tuberous/Semi-tuberous and Thick-stemmed.  The genus Begonia is given in honor of the French patron of Botany, Michel Begon.

There are some varieties of Begonias which grow well in our climate such as the Begonia semperflorens which bears clusters of pink flowers and the cane-stemmed variety B. coccinea commonly known as 'Angel's Wings' which is capable of growing up to 6ft tall.  This beautiful plant has spotted leaves, clusters of hanging flowers and fruits.

The flowering tuberous types such as the B. tuberhybrida, B. multiflora which have beautiful rose-like flowers are not suitable to be grown in  our climate.

The original Begonia rex came from India and sadly this species does not exist anymore.  The Rex-Cultorum Begonias which are imported from Holland and Malaysia are hybrids of the original and related species.  This type of Begonias are suitable to be grown as potted houseplants in a balcony or corridor.

Light

Begonias like filtered light but no direct sunlight.  The correct amount of light is necessary to  produce the colorful leaves.  As Begonias tend to grow towards the light, turning the pot every now and then may be necessary.

Water/Moisture

Begonias need well-drained soil and lots of moisture.  Allow the soil to dry slightly in between watering and spray-mist the air surrounding the plant but do not spray at the plant directly.  Never spray on the leaves as this will cause it to rot easily.  Placing Begonias on a pebble tray to provide moisture is highly recommended.

Fertilizer

Feed regularly with a liquid flowering houseplant fertilizer. Foliar feeding and leaf shine sprays are not recommended for Begonias.  B. rex hybrids do produce tiny insignificant flowers which should be cut off so that the plant can channel it's energy in producing the colorful leaves.

Propagation

*For the cane-stemmed types, propagate from healthy and mature stem cuttings.

*The rhizomatous varieties can be propagated by dividing the clump of rhizomes with a sharp clean knife.

*Propagation can also be done by leaf cuttings:

1)     Use a pencil to make a hole and insert a healthy leaf stalk at an angle into either perlite, vermiculite or a   sandy potting medium.  Moisten the medium and use one half of a recycled soft drink bottle to cover the leaf to provide the warmth and moisture for seedlings to grow.  If using the top half, remove the bottle cap and for the bottom half of the bottle, make some cuts at the base for air circulation.

2)    Put a shallow layer of potting mix which is meant for raising seeds and seedlings in a recycled cell pack (strawberries are stored in these packs for sale at the supermarket).  Make cuts on the veins of a healthy leaf and pin it to the potting medium with the top part of the leaf facing upwards.  Carefully moisten the medium and close the cell pack and wait for seedlings to appear.

For the above methods 1 & 2, seedlings can appear anywhere between 4 to 6 weeks or even longer, so be very patient.  Watering must be done very carefully.  Lightly moisten the soil and never over water.  Transplant the tiny seedlings with care as not to damage the delicate roots.  Begonias like well drained soil and do not cover up to the crown.  The young leaves appearing from the crown can easily rot if the crown is surrounded by moist soil

Pests/Diseases

Begonias can suffer from botrytis, mildew attack and crown rot.  Avoid over-watering and remove dead plant parts promptly.  Dry leaf ends indicate lack of humidity.