Gloxinia

Gloxinia: how do you recognise it?

Habit

Compact tuberous plant forming a rosette, about 25 cm tall and 30 cm wide.

Foliage

Large, oval to rounded, thick and velvety-haired, dark green.

Flower

Large bell-shaped trumpets, often 5–8 cm across, in purple, red, pink, white or two-tone, from May to August.

Tuber

A thick underground tuber in which the plant stores reserves during its rest period.

Origin

Brazil: warm, humid and partly shaded.

Flowering: May–August · Plants: February–March

Why grow it?

• Generous flowering from May to August, with large, velvety bell-shaped flowers in many colours.
• Compact: fits on a windowsill or small table.
• Large, velvety leaves form a green base beneath the flowers.
• Can return year after year: the tuber rests in winter and sprouts again in spring.
• A colourful, long-flowering plant for a bright spot without fierce sun.

Gloxinia: where does it grow best?

• Half shade: a bright spot without direct sun, which scorches the leaves. An east- or north-facing window is ideal.
• Light, humus-rich, airy compost (slightly peaty) with perlite, slightly acid to neutral.
• Evenly moist during growth, but never wet.
• Room temperature of 18–24 °C and never below 15 °C.
• Protect it from draughts and dry air: the buds drop otherwise.

Light

Bright, out of direct sun

Potting soil

Multi-purpose compost or airy, humus-rich compost

Acidity

Acid or neutral

Watering

Moderately

Size

0.25 m tall, 0.3 m wide

Temperature

Minimum 15 °C

Goes well with

• African violet: A related houseplant with the same light and humidity needs and small flowers as a contrast.
• Begonia: Also flowers on a bright windowsill and has attractive foliage.
• Boston fern: A light, green leaf shape next to the velvety rosette.

Gloxinia: when and how to plant it?

Plant in February–March.

1. Start the tuber in February–March; choose a firm tuber without soft patches.
2. Use a shallow pot of 10–12 cm with a drainage hole and light compost with a little perlite.
3. Lay the tuber with the hollow side up and cover it with no more than 1 cm of compost.
4. Put it in a bright, warm spot (about 20 °C) and water sparingly at first: only more once shoots appear.
5. The first shoots appear after 2–4 weeks; then give more light and water.
6. Do not repot a bought plant in flower during flowering: put it in a bright spot and water regularly.

Care

Water

Keep the compost evenly moist, but not wet. Pour lukewarm water into the saucer or carefully onto the compost, without wetting the leaves: cold water and wet leaves cause spots and rot.

Feeding

From the first shoots until the end of flowering, a flowering-plant fertiliser every 2 weeks at half strength. Then stop.

Humidity

It likes humid air, but do not mist the leaves: stand the pot on a tray of wet clay pebbles.

Deadheading

Pinch off faded flowers with their stalk: this encourages new buds and prevents mould.

Rest period

After flowering (August–September) water less and less; the leaves die back. Keep the pot dry at 10–15 °C until February.

Tip: After the rest, lay the tuber with the hollow side up and barely cover it: planted too deep, it rots.

Gloxinia: when to prune it?

When: It is not pruned, but you remove faded flowers during flowering and dead foliage after flowering.

How:

• Pinch off a faded flower with its stalk at the base.
• Remove yellow or dead leaves right down to the tuber.
• When all the foliage is yellow and dry (August–October), cut it off 2–3 cm above the tuber.
• Use clean scissors.

Caution: Do not pull the foliage out of the tuber: this can damage the tuber.

Pruning calendar and basic rules

Propagation

Leaf cuttings

In May–July: take a healthy, whole leaf with 3–4 cm of stalk, push it in at an angle into moist, airy cutting compost and keep it warm (about 22 °C) under plastic. After a few weeks a small tuber forms with new shoots; it takes months before it flowers.

Seed

The seed is very fine: sprinkle it in February–March on moist seed compost without covering it, and keep it light and warm (20–24 °C). It takes several months before you have a flowering plant.

Gloxinia: how does it get through the winter?

• Not hardy: the growing plant wants at least 15 °C. The resting tuber is kept dry at 10–15 °C, in its pot.
• During the rest, give little or no water, at most a little each month, so the tuber does not shrivel.
• In February–March lift the tuber from the old compost, remove soft or rotten parts and repot it in fresh compost.
• Then put the pot somewhere warm and bright to start again.

Diseases and pests

• Grey mould: Grey, fluffy mould on flowers and leaves when the leaves are wet and the air is humid and still. Remove affected parts, do not water over the leaves and ventilate.
• Wilting buds: Caused by draughts, dry air or fluctuating temperatures. Find a fixed, sheltered spot and raise the humidity without misting.
• Spots on the leaves: Caused by cold water or water drops in the sun. Use lukewarm water and avoid wet leaves.
• Tuber rot: The tuber becomes soft and smells. Too much water, especially during the rest. Water less, remove rotten parts and repot in fresh compost.
• Thrips and mites: Pale streaks on flowers, deformed buds or curled leaves. Remove affected parts and isolate the plant.

Through the year

• January: Tuber at rest: dry and cool (10–15 °C).
• February: Repot the tuber and start it at about 20 °C. Little water.
• March: Repot. Let the shoots grow. Put in a bright spot.
• April: Growth: water more. Start feeding every 2 weeks.
• May: First flowers. Feed. Pinch off faded flowers.
• June: Flowering. Water without wetting the leaves. Take leaf cuttings.
• July: Flowering. Take leaf cuttings. Feed.
• August: Last flowers. Stop feeding. Gradually reduce watering.
• September: The leaves die back. Little or no water.
• October: Rest. Cut off dried foliage. Keep the tuber dry and cool.
• November: Rest. Keep the tuber dry and cool.
• December: Rest. Hardly any water.

Did you know?

• The genus is named after Wilhelm Sinning, a German gardener at the botanical garden in Bonn.
• The plant belongs to the Gesneriaceae, like the African violet.
• It is often called gloxinia, but the true Gloxinia is a different genus.