Botanical Name: Begonia masoniana
Origin: Iron Cross Begonias originate from Southeast Asia.
Height: These house plants grow up to 30 cm (1 ft) tall.
Soil: Begonia masoniana prefers the same type of potting mix as African Violets.
Light: This house plant likes bright, but indirect light and will thrive under fluorescent light.
Humidity: Iron Cross Begonias need moderate to high levels of humidity. Wet pebble trays and/ or room humidifiers will raise levels sufficiently. This house plant needs to be kept away from drafts.
Temperatures: Like most Begonias, Begonia masoniana does not tolerate temperatures below 13 degrees C (50 degrees F) at all. Ideally, it should be kept in temperatures ranging between 18 and 24 degrees C (65 to 75 degrees F).
Water: B. masoniana needs to be watered thoroughly, allowing the top of the potting mix (approximately 2.5 cm/ 1 in) to dry between watering sessions. As the leaves are prone to mildew and spot easily, it is essential to avoid splashing water onto them.
Fertiliser: Dilute a liquid 10-10-5 fertiliser by half and feed the plant once a month all year round. To prevent fertiliser burn, feed only after watering, ensuring the soil is already moistened. If the plant enters a dormant state, cease feeding until it starts growing again.
Propagation: Stem cuttings of around 8 cm (3 in) in length (with leaves) will root easily in sterile, moistened potting mix in early summer. To increase humidity until new leaves form, cover with a glass cloche or plastic.
Description and Care Tips
The reddish-brown centre pattern resembling an iron-cross make the puckered, bright green leaves of the Iron Cross Begonia easily recognisable. Stunning on its own due to its magnificent foliage, Begonia masoniana also makes a formidable addition to dish gardens and groups of tropical plants.
On occasion, this house plant may produce sprays of insignificant flowers, which are typically pinkish-white in colour. As they really are hardly worth mentioning, it is best to pinch these flowers off while still in bud, as this will promote growth of healthier, bigger leaves.
The best leaf colour can be achieved by giving the plant plenty of indirect, but bright light. Even fluorescent light will have this house plant thriving.
It is important not to over-water this plant. Begonia masoniana has rhizomatous roots - which will store water - and unless the soil is allowed to dry a little between waterings, root rot may occur. If the plant shrivels, it is likely that it has entered a dormant state. This is not uncommon with begonias.
What it needs now is high humidity. Stop watering it and cover it with plastic - or place it under a glass cloche - for around six to eight weeks, keeping the temperature at around 16 degrees C (60 degrees F) throughout this period. Once new leaves appear, bring it out from under its cover and resume the regular watering and feeding routine.
In spring, move your Begonia masoniana into a pot just one size larger than the old container. Only lightly tamp down the fresh soil, as this house plant prefers to have a little bit of air circling its roots. Naturally, the pot should have drainage holes.
Unfortunately, the leaves and stems of Begonia masoniana are prone to powdery mildew - a white, dusty fungus encouraged by high humidity and poor air circulation. Providing adequate circulation (but keeping the plant away from drafts and drying air conditioning/ heat vents) and regularly checking for the fungus is therefore essential. If an infection is detected, affected leaves/ stems should be removed immediately. It may also become necessary to treat the plant with a suitable fungicide.