Gloxinia (Sinningia)

Gloxinia flowers

Pretty, low-growing tender plants, with large bell-shaped or tubular summer flowers. Usually grown as a conservatory plant or houseplant in the UK, or as part of a seasonal bedding scheme.

Family: Gesneriaceae
Botanical Name: Sinningia speciosa
Common Names: Gloxinia

Foliage: Deciduous, simple, fleshy green leaves.

Flowers: Large, cup-shaped, ruffled flowers. Single, semi-double or double blooms, in various strong colours.

Flowering Period: Spring to early autumn.

Soil: Moist but well-drained, humus rich soil or bulb fibre.

Conditions: Best in part shade. Grow in an east, west or south facing aspect, in a sheltered position.

Habit: Low growing.

Type: Tender, tuberous-rooted perennial or annual.

Origin: Brazil.

Hardiness: Tender in the UK - protect from frost.

Planting and Growing Gloxinia

Start the tubers off in spring by placing them in trays on a layer of compost in a gentle heat. Keep the compost just moist and once the shoots are 2-3in high, pot-up each tuber in a 4in pot. Maintain warmth and moisture and place in a bright area that is shaded from full sun. They can also be transferred outside once all danger of frost has past.

Taking Care of Gloxinia

Water liberally once well rooted. Use water at room-temperature and do not get the leaves wet. Transfer to larger pots as soon as they become pot-bound.

To improve flowering, apply an all-purpose flowering plant food (slightly higher in phosphorus and potassium) every few weeks, or use a slow release form. Do not over fertilise.

Once flowering has finished, lift, clean and dry-off the tubers. Store the tubers a peat free compost such as coconut fibre.

Although the species form is a repeat flowering perennial, many modern hybrids have been bred to produce a more spectacular show in the summer. Unfortunately once the flowers of these hybrids fade the plants rarely come back with the same vigour. Therefore these are best grown as annuals and discarded after flowering.

Pruning

Deadhead regularly to extend the flowering period.

Pests and Diseases

Susceptible to attack by aphids and red spider mite. Yellowing leaves indicate lack of nutrients or cold draughts.

Propagating Gloxinia

Perennial houseplant species are usually grown from tubers, from which leaf-cuttings can be taken in summer.

Hybrid annuals can be sown at the end of January in trays of seed compost, thinly covered with coarse sand. Apply bottom heat of about 70°F. Prick out as soon as large enough to handle and gradually reduce the temperature to 60°F. Pot-up singly into 4in pots and maintain temperature. Keep moist but take care not to get leaves wet. Harden off and plant outside once all danger of frost has passed.

Varieties of Gloxinia

Gloxinia speciosa 'Brocade Double Mixed' (F1 Hybrid) is a dwarf, compact plant with small dark green, velvety foliage and fully double-flowers, in a range of colours. Seed available from Thompson & Morgan.

Sinningia speciosa 'Corina' produces fresh green foliage and large cup-shaped showy red flowers. For sale at Crocus.

Sinningia speciosa 'Hollywood' has lilac-purple flowers with a white throat.

Sinningia speciosa 'Violacea' bears velvety textured, dark purple/violet flowers with ruffled petals.