Gloxinia -A Proud Spirit

During Victorian times the classic Florist Gloxinia, Sinningia speciosa, was a favourite floral Christmas gift for men because in the floral ‘language of flowers’ they represent “A Proud Spirit " and “Love At First Sight”.

Quite a convenient complimentary double message for Christmas as well as Father’s Day! These are proud plants born of humble beginnings. Their nearest wild relatives are small bell-shaped flowering, herbaceous groundcovers growing from small tubers that sprawl across the moist lower canopy of the Brazilian rainforest.

This interesting groundcover with pretty bell-shaped blue and purple velvet flowers was first introduced to the larger world of Botanists and then Gardeners from Brazil in 1817. At that time it was considered to possibly be a Campanula but was eventually classified as Gloxinia speciosa. The small Gloxinia genus contains the pretty powder blue bells of Gloxinia perennis, plus G. erinoides, G. xanthophylla and a couple lesser known species all cultivated occasionally in gardens and as container plants in tropical South America. Each of these Gloxinia species shares a similar flower colour, form and shape; somewhat similar habit of growth and growing environment; and each feature those distinctive oval velvet leaves.

Since then, with the advancement of genetics, it has been determined that the original Brazilian Gloxinia speciosa which has since been transformed into the modern Florist Gloxinia hybrids was indeed a different genus of its own. So it was reclassified as Sinningia speciosa. This revelation then changed its botanical classification to become yet another member of the massive Gesneriaceae Family with 150 genera and at least 3200 species.

The Gesneriaceae Family is a vast melting pot of perennial ground covers, herbs, shrubs and even trees and vines all sharing a somewhat similar flower form and a vaguely related leaf structure. Included in the Gesneriaceae Family are such botanical favourites as: Achimenes; Aeschyanthus (Lipstick Plant Vine); African Violets (Saintpaulia); evergreen tropical climbers Asteranthera; tropical groundcover and vining Columnea; groundcover houseplant tropicals Alsobia and Episcia; climbing and trailing groundcover Sarmienta scandens; herbaceous shrubby tropical Kohleria (a Humming bird magnet); sprawling tropical and uniquely-flowered Neomortonia; herbaceous, shrubby and sprawling tropical Seemannia; well known groundcover and (sub) tropical houseplant Streptocarpus; and hundreds of lesser-known Family members.

This reclassification so confused and stunned the global world of Gardeners and the general public that they reacted in classic style and simply ignored this information, and persisted in calling this lovely plant they so cherished: Gloxinia.

Today’s spectacular Florist Gloxinia hybrids are hardly recognizable creations of Humankind produced through repeated cross breeding between the original species and its descendents. Florist Gloxinia (Sinningia) is easily propagated from seed which is genetically somewhat unstable. This results in numerous flower and leaf variations. The finest of these can then be reproduced through cuttings and now genetic cloning to produce new varieties.

Florist Gloxinia is a tuberous rooted perennial herb. The small hairy oval corm-like tubers first produce tiny leaf shoots in Late Winter through Spring which soon grow into a very short, succulent and stocky-stemmed plant featuring alternate, closely grouped, large, oval, velvety leaves. The first flower buds emerge from between where the leave petiole attaches to the stem and continue to develop upward from each leaf to the top of the stocky stem. Then a cluster of buds form in a very tight cluster at the very top of the succulent stem. These buds open from the bottom leaves upward to the top and cluster in a close grouping. The secondary side shoots do the same budding and flowering. This creates a very similar appearance to a large African Violet but with much larger nodding or upward facing bell-shaped velvet flowers held tightly together in an impressive cluster of richly coloured velvety blooms.

These very showy trumpet-shaped flowers follow in profusion over a long period. In some hybrids these velvety blooms are sweetly scented. Colours include many shades of blue, burgundy, carmine, cerise, crimson, pink, scarlet, crimson, lavender, lilac, mauve, purple, scarlet, pink, purple, white, wine red and purple to nearly black purple. Flowers feature solid colours, bi-tones with a contrasting picotee edge often in white but sometimes blue, purple or red. Some new hybrid flowers feature attractive lining or spotted patterns or blushes of complimentary colours or contrasting markings and shades plus ruffled and wavy petal margins. Almost all the colours and patterned forms appear in single, semi double, hose-in-hose and fully double forms.

Reflecting their (sub) tropical South American rainforest origins, Gloxinias demand very bright light (but shaded from direct hot sunshine), humid conditions with good air flow, and consistently warm conditions sheltered from temperature extremes, pelting rain and pests. They grow best in a warm lathe house or lightly shaded glasshouse. Gloxinia are also easily grown indoors anywhere that African Violets will grow, but preferably with brighter light. They are easily grown under florescent tube lighting or special agricultural ultraviolet ‘gro-lights’.

Gloxinias in their wild state are naturally Summer flowering. The very best plants are produced to create blooms through the warmer Summer months. But because Gloxinias come from tropical regions with near constant heat, humidity and light and because they also respond well to dry and wet seasonal climatic variations, they can be artificially forced to flower almost any time.
Tubers normally go dormant in the tropical Winter which is somewhat cooler to mild and dry. Then new shoots emerge with the first returning rains in Spring; producing their flowers Summer through Autumn before returning to dormancy.

Because of this natural cycle, Gloxinia tubers can be held over in bags, flats or pots maintained in a cool, dry state at about 45F/7.2C degrees. Provide only enough humidity and/or moisture to keep the corm-like tubers from shrivelling while they remain dormant. After 4-6 weeks or more of dormant rest, these tubers can then be brought out in succession into the heated glasshouse and started into active growth. Consequently, with proper attention to correct feeding, lighting and watering, Florist Gloxinias can be produced as flowering ornamental plants throughout the year.

For the home Gardener, much better and easier results occur when the tubers are grown according to their natural cycle. Thus the tubers usually grow to their very best when started in the Late Winter (with bottom heat) or Spring. This will produce flowering plants by Early Summer with blooming continuing into Autumn followed by fading and dormancy. So in the Southern Hemisphere, to have them in bloom around the Christmas holidays the tubers should be planted Early to Mid Spring (September-October). In the Northern Hemisphere, tubers started in March-April will usually begin flowering in June or July.

Choose a 15-20cm/6-8incm pot and fill with peaty/humus/sand potting soil similar to the potting mix used for African Violets. When making up a suitable potting mix at home combine together: 1 part sharp sand; 2 parts screened loam; 1 part leaf mould; ½ part dry screened cow manure; and to every bucket of mix add: one handful/1/4 cup blood and bone or bone meal; one handful (1/4cup) little slow release fertiliser; one handful dolomite lime. If in doubt about adding fertiliser or lime always remember that less is always better than more, which can prove burning and caustic if mixed in excess. More fertiliser can always be added later as the plants begin to grow and mature.

Once all ingredients are thoroughly mixed together, squeeze the mix in the hand. If the mix breaks apart instantly it is of correct consistency. If the mix sticks together in a ball, it is too heavy and more sand, river gravel or small-grade pumice should be mixed in to further lighten the mix. This mix can be stored for short periods if it remains in a dry state.

Plant the corm-like tuber at or just below the soil surface. Water deeply and place in a warm corner with very bright florescent or warm morning sunlight surrounded by near constant temperatures between 20-28C/68-82.4F degrees with high humidity. No heavy watering after that, just keep lightly moist until the first leaves appear then water lightly but regularly to maintain even moisture levels. Maintain these bright, humid and warm conditions throughout the growing cycle of the Gloxinia.

Liquid feed every two or three weeks especially as flower buds emerge. Liquid African Violet fertiliser is very effective. Or use a liquid fertiliser that is either equally balanced such as 20-20-20 or chose one slightly higher in Phosphorous and Potassium than Nitrogen such as 5-10-10, etc., especially as flower buds begin to appear. A dusting of slow release Tomato Fertiliser over the potting soil will boost flower size, quality and quantity of bloom. Gloxinias respond to almost exactly the same fertiliser ratio that produces excellent quality Tomatoes! Be very cautious with any type of feeding as too much can burn the delicate plant tissues!

Avoid any liquid fertiliser or water spilling on foliage and flowers as this can disfigure the plant with spotting or flower rot. Water either on the soil surface using a watering can with a long, narrow spout carefully placed between the leaves. Or a much safer approach is to water into a saucer or dish beneath the pot. Leave the fertilised water in the dish for about an hour or so and then remove any excess. Always water when surrounding environmental conditions are bright and warm, never during cool or dark conditions that might result in chilling which could lead to root rot.

Gloxinias can be propagated by splitting the tuber with a sharp knife and replanting each section with a shoot or “eye” attached. This is best done in Spring. First place the tuber somewhat buried in damp peat, propagating sand, sphagnum moss, untreated sawdust, etc. so that the tuber begins to sprout. Then do the cutting with a sharp knife. Even a small section of tuber will produce a new plant provided it has a healthy eye attached. Once each eye and tuber section is cut away, dust the open wounds of the tuber with powdered Captan, Charcoal or Sulphur powder. Then set aside the small cut up sections for a few hours to let then callous and dry out a little before planting. This will help prevent the cut tuber from rotting. It is often a good idea to place these cut up tuber segments in a small pocket of sand within the potting mix in their pot. This helps insure perfect drainage around the tuber until it revives and puts out healthy roots of its own. Usually such cut up segments will grow and produce flowers almost as quickly as healthy, mature tubers.

Gloxinias are also rather easily raised from seed. Seed is very fine. This can be started any time from Early Spring onward to Autumn, even during Winter in a controlled heated glasshouse environment. First mix a quality houseplant potting soil or seed raising mix with a little extra peat moss and a dusting of lime. Bake this mix at 400F /204C degrees for one hour to sterilise the mix. This helps prevent damp-off fungus disease which often causes young Gloxinia seedlings to collapse suddenly while still quite young. Then apply a dusting of Captan over the sterilised potting soil and mix this in. The Captan helps control any moss that might form over the mix.

Fill cleaned and washed small punnets, shallow trays or pots with the sterilized mix. If using old pots sterilise them with soapy water to which a small amount of bleach has been added. Moisten the mix thoroughly then sprinkle the seed lightly over the moist and sterilised mix. Cover with a sprinkling of peat moss or fine screen sterilised soil.

Gloxinia seed needs light to germinate as well as constant humidity and warmth. Place the seeded containers under very bright florescent lights or agricultural ‘Gro’ lights or similar botanical lights used for growing African Violets indoors. Keep the lights about 20-30cm/8-12in above the seedling punnets. Maintain constantly humid and warm environmental conditions. Germination should begin within a couple of weeks but can be erratic. The Gloxinia seedlings start out as tiny green specks. Once they develop their first true seedling leaves, carefully prick each of them out with a pointed skewer stick or knife point into individual 4in/10cm cube pots and grow on until well established. Then shift them into 6-8in/15-20cm pots to grow on to flowering.

When first transplanting baby Gloxinia seedlings from their sterile mix terrarium environment to their first starter pots, be very careful to gently coax out the tiny roots from the soil. From an early age the seedlings begin to form a small whitish corm-like tuberous root system which is very brittle. This root can be unexpectedly large compared to the size of the seedling leaves. If this breaks away from the green seedling top during transplanting, the seedling will usually die.

With the skewer stick or sharp knife, dig in rather deeply below and well to the side of each seedling and gently lift. Take any clinging soil along with the corm-like tuberous root. Then make a small hole in the potting soil of the small cube pot and drop the seedling into this. Then carefully push the soil up around the seedling, covering the roots entirely.

Seedlings are much better watered-in from below as are the Gloxinia plants throughout their entire growing and flowering cycle. When first transplanting the tiny baby Gloxinias, it is often better to saturate the soil from below and gently shake or tap the edges of their growing container to shift the soil into place and settle the seedlings into their new soil.

Alternatively, the seed can be started in a very bright and warm terrarium. Or create a simple home-made terrarium from a plastic soft drink bottle. First run the plastic disc base of the soft drink bottle under very hot water to melt the glue on the base. Then remove the clear plastic casing, cut off the top and invert this over the plastic base to create a plastic bell jar terrarium. Then fill the base with the sterilized soil mix and place the bell jar terrarium in a bright morning or afternoon sun window. Some people place a thermometer inside the bell jar to make sure temperatures do not get too hot if the terrarium could ever be exposed to direct sunlight during sunny days. Make sure the bell jar is brought in away from chilling night time temperatures.

Seed germinates quickly in warm, humid conditions but may not do so well if temperatures ever drop or the soil dries out or they have less than necessary illumination. But even with the home-made terrarium method, at least a few seeds should germinate.

Seed can either be purchased from a reputable Seed Merchant. Or seed can be easily harvested from mature flower seed capsules. Wait until the seed capsule begins to yellow or brown on the mature plant. Once the brown capsule begins to split open, it can be carefully cut away from the parent plant. Place this on a sturdy sheet of white paper possibly within an open  shallow, sheltering box and place in very bright and warm place. The seed will soon ripen and begin to spill from the opening split capsule. It is best to plant this immediately as it does not keep for long. Gloxinia seed is genetically somewhat unstable; so any one seed capsule will often produce off-spring that demonstrates a variety of different colours and forms.

To reproduce an exact duplicate of a particular Gloxinia hybrid, this is accomplished either through genetic cloning, or very easily at home through leaf cuttings. Simple cut a mature medium-sized leaf from around the middle section of the plant. This is usually done during the warmer Late Spring, Summer and Early Autumn months. Very large leaves also work but are more difficult to manage and smaller leaves often rot away.

Place the leaf in a small pot partially filled with moist propagating sand or seed raising mix. Fill in around the leaf with more mix up to where the leaf stem joins the leaf itself. Water once thoroughly and place in a terrarium-type environment similar to what has been described earlier for starting seed. The leaf in its propagating pot can be place within a plastic bag which is drawn up around the cutting creating a make-shift terrarium environment. If kept bright, humid, moist and warm, the leaf cutting will usually strike quickly under ideal conditions. At first fine roots will emerge underground and then within a few weeks time a tiny plant will emerge from within the soil near the cut stem end or from near the leaf and stem axis.

Seedling Gloxinias and cuttings usually take at least 4-6 months or longer to produce their first flowers. If healthy young plants begin to die away and go dormant, just allow them to dry out a little and patiently wait; they should reappear from tiny tubers the following Spring. And all should be ready to flower within one year.

Because Gloxinias are native to tropical climates with Summery wet season and Wintry dry season, they naturally go dormant as light reduces and the season cools and dries out. So after a Florist Gloxinia plant has reached maturity and flowered for some weeks or months, the plant will begin to slow down producing fewer and then no new buds and leaves; then eventually the entire plant will begin to fade and wither. This is completely natural and necessary that they rest in complete dormancy.

Once dormancy approaches simply reduce both water and food, allowing the foliage to wither naturally and the tuber to ripen. Then once the plant has nearly completely withered away, either store the tubers intact in their pots in a cool, frost free, dark, dry spot over the Winter. Or remove them from their pots and store in plastic bags in lightly damp peat or sphagnum moss in a cool dark place. Gloxinia tubers store best at temperatures around 45-55F/7.2-12.7 or slightly warm but never colder. And always keep them just damp enough so that the tubers do not shrivel but never wet, which will surely lead to rotting.

Then in Late Winter throughout Spring into Early Summer the tubers can be brought out of dormancy as soon as they begin to sprout. Repot them into fresh soil mix and start the cycle again. When well-grown, Gloxinia tubers slowly increase in size over several years before they finally finish. Often when a tuber reaches a large size it is best cut into several pieces which will revive the tuber and produce a number of plants that will continue to grow on. Otherwise once the tubers become quite large, they sometimes completely collapse, or naturally divide into several smaller tubers usually during their next period of dormancy.

As the tubers increase in size up to nearly the size of a chicken egg, so does the overall size of the plant which can reach nearly 60cm/2ft or more across. The size of the blooms also increases and so does the number of flowers. A mature and well-grown Gloxinia can make an impressive display of well more than a dozen blooms continuously opening in succession above a beautiful rosette of velvety leafs for months on end! It is possible for a large specimen that has been potted-on into a larger container or basket to produce a rosette of velvet leaves 60cm/24in across with a flower mass 30cm/12inches across; truly a spectacular site!

No wonder in the language of flowers the Gloxinia represents ‘A Proud Spirit” and “Love at First Sight”. Anyone who grows one well will surely fall in love with what they have accomplished and certainly be a very ‘proud spirit’!

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