How to Grow, Propagate and Care for Rex Begonias
The Rex or Painted-Leaf Begonias are rhizomatous, clump forming, tender perennials that are only
hardy in zones 10-12, so they are normally grown as house plants.
Rex Begonia leaves vary considerably in texture, size, shape, patterns and colors.
The small, pink or white flowers that may appear at any time of the year are insignificant
compared to the foliage,
but they are charming nonetheless.
Growing Requirements for Rex Begonia Plants
Rex Begonias grow best in bright, indirect sunlight coming from an east or west window.
Fluorescent grow lights are also an excellent alternative to natural light for these plants,
and in many cases will intensify the foliage colors.
When potting, set the plant with the crown slightly above the soil line.
They should be planted in a porous, slightly acidic planting mix that contains some peat moss
and leaf mold. African Violet potting mixes work well for Rex Begonias.
Allow the top 1" of soil to dry before watering, then water thoroughly.
Overwatering can lead to root or crown rot! Wet foliage can cause problems with mildew.
Always use room temperature water when watering house plants.
House plants should never be allowed to stand in water for more than a few hours.
Painted-Leaf Begonia plants thrive with daytime temperatures of 70°-75°
and 60°-65° at night. NEVER lower than 60°!
They require a humidity level of at least 50% and appreciate periodic, light mistings.
Provide additional humidity by setting the plants on shallow trays filled with moistened pebbles,
or a humidifier, especially during the winter months.
Feed actively growing plants in early spring and again in early summer with a slow-release plant food,
or every 2 weeks using a ¼ strength dilution of a soluble, complete fertilizer (23-19-14).
Decrease feeding in early fall and stop altogether in the winter. Do not over-fertilize!
Your Begonia Rex may go dormant in the winter and possibly drop its leaves.
If this happens, continue to water sparingly until spring when new leaves will re-appear.
If your Rex is growing where it only gets light from one side (i.e. a window sill),
turn the pot ¼ each week to maintain even growth.
Foliage color may fade under low light conditions. Consider using a grow light.
Remove any dead leaves and other debris around plant regularly.
Rex Begonias enjoy spending the summer in a shaded part of the garden.
Always be sure to check for insects and pests before bringing your plants back indoors!
Rex Begonias are susceptible to attacks from mealy bugs.
Propagating Rex Begonias and Growing them from Seed
The easiest way of propagating new Rex Begonias is with whole leaf cuttings struck in a mixture of moist peat moss and perlite.
Two other ways of propagating multiple new Begonia Rex plants from a single leaf are by methods called wedge cuttings and split vein propagation.
These methods are a bit more complicated, but they allow you to create as many as a dozen new plants from a single leaf.
Begonia has extremely small seeds that require light for germination,
so DO NOT COVER them!
Start seeds indoors at any time.
Maintain a temperature of 70°-75° within the growing medium until germination, which takes 15-20 days.
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