Growing Alpine and Doulbe Auriculas

: Howard Drury; Fact Sheets; 01 April 2022; Hits: 555

Growing Alpine and Double Auriculas

By Howard Drury and Gwen Baker

Alpine and double auriculas are usually grown in pots for exhibition, but as they are hardy plants most can be grown in the garden in a shady place with good drainage. These notes are for pot plants.

All Florists' auriculas, we believe, are descended from two primulas growing wild in the European Alps, the yellow Primula auricula and the red‑flowered Primula hirsuta (or rubra.) These still grow and cross today and their fertile hybrid is called Primula pubescens All three, like other high Alpines, grow in thin gritty soil, rich in humus and minerals but probably low in nitrogen. The are accustomed to cool conditions at all times, snow cover in winter, unlimited snow‑melt water in Spring, and then slightly drier conditions in summer, and always, always water draining away freely. They can withstand cold, beyond anything our climate in Britain can reach, but they go semi‑dormant in winter and in this condition are kept by snow in an atmosphere where any water is locked up by cold. These conditions we must try and reproduce if we wish to grow them to the best of our ability ‑ and who would wish for less? The greatest threat to their well-being is damp muggy conditions in winter when they are resting, or excessively hot dry conditions, as held in the summer of 1989. They are also venerable when we repot them or take offsets, as their water supply is cut off till the new roots take hold.

Cultivation

Auriculas go semi‑dormant in late autumn and remain in this state till about mid-February. They die down to a tightly folded core of leaves, the resting bud, and it is at this time the flower buds develop inside. Many beginners fear their plants are dying when yellow leaves develop in November, but this is normal as the plants adapt to lower light levels and increased cold. These leaves can be left till they are sere and dry, when they can be gently removed ‑ sideways, using two hands to prevent the development of grey mould ( Botrytis). To protect them from the all pervasive wetness of our winters they should be housed under rain cover in a cold greenhouse, a frame or just a pane of glass supported on bricks. The aim is to keep them dry, not warm. Ventilation is all important and the greenhouse or frame should not be shut down. Some growers recommend shutting doors and windows in fog or when it is snowing, I have never bothered and no harm has come.

The compost in the pots should be kept just damp ‑ complete drought will kill almost any plant ‑ but now they are just ticking over and use very little water, using most in bright windy weather. Flick the leaf‑cone, only if they look or feel limp do they need water, on a day when no frost is forecast for the night. Do this before midday, so any surplus can drain away, and give them at most about a dessert spoonful, carefully at the side of the pot, so no water gets on the leaves. In all I probably water twice, sparingly between November and February.

With the lengthening daylight, about mid-February but depending on the season, the nose cone begins to open. Watering regularly should now begin, a little at first, then in increasing amounts as growth rate increases. Give them a balanced feed about the beginning of March, and water with weak potash‑rich fertilizer thereafter, simulating the melting snow of the mountains. On no account give them strong doses near flowering time, as this distorts the pips, giving monstrous or cockled trusses. The plants should be inspected, any remaining dead leaves removed, and it is a good time to take offsets, as they have a whole year to become established. I like to turn the plant out onto my hand and inspect the roots for the white root aphids, while dead roots probably mean root rot or vine weevil grubs. The topsoil is dry and falls away easily and may be replaced with fresh compost to cover the top feeding roots. Plants can be completely repotted if needed, but disturbed plants rarely win prizes, so take care if removing offsets to disturb as little as possible.

The flower bud(s) should now be seen lengthening, there are two sorts, side trusses and centre trusses. It does not make much difference which ones you keep for showing (unlike Edged auriculas where the centre truss is mostly inferior) but one or the other should be removed to concentrate all the plant's energy into one. If only wanted for greenhouse decoration, both can be left. Rotating the pot a quarter turn regularly will help the plant grow evenly, using the labels as guides and always the same direction, about once or twice a week. It is light rather than heat which advances the truss, but keeping the plants frost‑free undoubtedly helps. Eager Showmen do use heat, but a light covering, such as newspaper or bubble plastic on frosty nights, will help. Frost does not harm the plants, only the rising buds, perhaps distorting the growth. Now they can scarcely be over-watered.

Shading should be provided to a greenhouse from late March or early April until late September, as too hot a sun scorches the leaves; roller blinds, woven plastic, whitewash all have their advocates. The shading must not impede the ventilation and is best fitted to the outside.

Flowering is dealt with under Exhibiting, but now is the time to enjoy the beauty of your plants, and if seed is required to make any crosses. Other spent heads should be pinched out just below the truss, and the stem left to wither and callus before removal; it should come away with a light pull. Now is the time to think of repotting and summer quarters. If left in spent soil the plants will stunted and unhealthy, if left in a greenhouse they run the risk of becoming too hot and falling prey to Red Spider, whitefly and greenfly. Control of these by chemicals is possible, but prevention is better, and a cool spot under a tree or in a shady open frame is best, as they get direct light and natural rainfall. Plants make food with chlorophyll and ultraviolet light, and this light is to some extent cut off by even the cleanest glass. The plants dislike too much sunshine, which can dry them up too fast and produce white burn‑marks on their leaves.

Light centred alpine auricula 'John Wayne'

Gold centre alpine auricula 'Bilbo Baggins'

Light centred alpine auricual 'Averil Hunter'

Routine inspection will determine if they are being attacked by slugs or snails, while a periodic dose of systemic insecticide will kill off most pests, such as greenfly, sciarid fly and the one specific pest of auriculas, Primula root aphis This pest surrounds itself with a white waxy coating looking like cotton wool, around the neck and the inside pot edge. It resembles the mealy‑bug found on cacti, but is mostly underground, not on the leaves. The aphids suck the roots of the plants, which debilitates them, and the wounds admit spores of fungal rots. It is a good practice to turn the plant out on to your hand and inspect the roots if this pest is suspected, the white patches giving it away instantly. A temporary control can be had by dabbing the wool with methylated spirit, which dissolves the wool and dehydrates the insects, killing them, but Systemic insecticide is the best thing to use as it kills more thoroughly and also kills other pests. It has little effect on the most serious pest now around, Vine weevil, though I have been shown an adult killed by malathion.

The adult Vine weevil eats semicircular bites out of the leaves, but the damage is done by the eggs it lays, which hatch out into fat white grubs with a brown head. One female can lay up to 1000 eggs, a sizable infestation. The grubs can gnaw away the roots completely, especially when the plants are dormant, and nothing is known by the grower till the last root is severed and the plant dies of lack of water. Some limited control is obtained by BHC, but the best defence is vigilance when the telltale bite marks are seen, repotting into fresh soil and safe disposal of the contaminated soil. The adults hatch out normally about June, and are nocturnal, hiding in the daytime. They look like a dark brown beetle with a blunt snout, if disturbed they remain still to be undetected, which distinguishes them from large spiders which run away and have eight legs. Weevils hunt by smell, so anything that disguises the smell of auriculas is beneficial. They also attack many other plants, especially those grown in peat based compost, such as fuchsias and begonias, sempervivum, Lewisias, Rhododendrons, etc, etc.

Repotting

The time of year to repot is one of the controversial parts of auricula growing, some advocating repotting directly after flowering is over, some advocating August or September when the heat of summer is over, as heat is detrimental to the new roots taking hold of the new soil. The type of pot and compost is also debatable; a loam based compost is best for clay pots, a peat‑based one for plastics, both need a good dash of grit to improve the drainage, or one of the proprietary substitutes made from volcanic rock etc, designed to charm the money from your purse. I use two parts JI II, one part peat‑based compost, one part horticultural grit. Peat based compost relies on feeding with fertilizer, as peat is sterile, and the added fertilizer gets used up after six weeks. Repotting may have to be spread out over a few weeks, according to the time available, but should not extend over the end of September, as new roots do not grow so readily in cooler weather unless you can provide bottom heat. I have re-rooted sick plants in November on my bedroom window sill over the radiator.

Plants of the same variety are best dealt with together, so that small offsets not warranting a separate pot can be put together. Offsets that have outgrown their pot can be potted on at any time and will grow away at once. Older plants need their roots inspected, and the old soil will shake off better if the plants are on the dry side. If rot is present, cut the carrot back till clean tissue, free from any streaks or dots of brown, can be seen, and cauterize the cut surface with lime, charcoal, sulphur or a lick of meths. If the rot extends up the middle of the carrot, it can be excavated and the cavity filled with sulphur like a hollow tooth. Often the rot is one-sided and a finger of sound tissue with good roots can be left. Do not be alarmed by rot, it is normal for the old carrot to die and be replaced higher up by new carrot and feeding roots. Any rooted offsets can be detached and potted up either separately or in trays, not forgetting labels with the name and the date, so you know in the future the age of that plant. Unrooted offsets will root readily in a peat/sand mixture, any unwanted offsets can be removed either with the knife or the thumb nail. Single crowned plants produce the finest flowers as all the plant's strength is concentrated, but some offsets are needed as one crown will only last about four years on average. Old growers used to have one "mother plant" for offsets and keep the others of that variety as exhibition plants. One way of providing many offsets is to behead a plant ‑ the removed part can be treated like any unrooted offset and rooted in sand with a plastic cloche on top, while the stump will grow a ring of offsets. The old stump is called a "stag" and might or might not rejuvenate itself if repotted.

Chose a pot that will just take the roots, never overpot. Place some drainage material in the base, a crock, a shell or plastic netting to prevent worms getting in, and on top of that a moisture reservoir, dead leaves, hortag granules or a little well rotted manure. Hold the plant in the centre and trickle in compost, ensuring the soil level is just below the first leaves. Press down gently, do not ram, tap down peat based compost. Give the plant a good watering, place below the staging or in another dry shady spot and leave alone for a fortnight or so till fresh growth is seen. Offsets go in 2.5" pots, most adults will go into 3", with potting on into 3.5" for flowering. Only exceptionally vigorous plants need a 4" pot, an over potted plant is inclined to rot in winter. Mother plants can go into 5" half‑pots. The first watering after repotting can well be laced with the recommended dose, of systemic insecticide or fungicide, though I admit I rarely use the latter.

The plants should be re-housed in the greenhouse about mid-September, and the shading removed. They should stand on a gravel tray of sand, so any excess water can drain away. Open slatted shelves are not recommended, as the small pots tend to fall over, and may desiccate too far in winter. I do not use polythene lining in winter, as the plants do not need protection from cold; my plants have often been frozen to the sand without harm.

Double auricula 'Prima'

Double auricual 'Samantha'

Double auricula' Ushba'

Showing

Alpine auriculas are divided into two classes, Gold‑centred Alpines and Light‑centred Alpines, and the distinction is important when showing, as the schedule is arranged with this in mind. Double auriculas have no subdivisions at the moment. As the truss expands, you will need to stake it and maybe thin some pips, depending on how many there are. I have seen 22 pips on a vigorous variety such as Mark, but nine or eleven are plenty, even allowing for the odd pip to be removed prior to benching. The first bud to develop is usually over‑big and often deformed, and can be removed without qualms, while any undeveloped pips in the centre should be nipped off with tweezers just prior to showing.

Staking is allowed as the plants have to be transported to the Shows and a heavy head of bloom could shear off, and staking is traditional anyway as farinose flowers (Show Auriculas) tend to stain adjacent pips. It also helps the truss to be better presented, but it should be done as neatly and unobtrusively as possible. Thin split canes, cut to the right length just beneath the truss, and green wool or silk should be used, I have also seen green wire hooks used. Do not tie too tightly till you are sure the footstalk has finished elongating. Have a pair of finely pointed scissors handy to nip off too high a stake, ends of wool, damaged pips etc. The old books recommend a pledge of cotton‑wool between the stem and stake, and this is permitted, but I find tying the wool in a figure‑of‑eight prevents bruising just as well and is more sightly. Cotton‑wool is also used to separate the developing pips, to ensure they have the right amount of room to develop fully, and can be left in for transport, but leaving the least bit in when benching will disqualify the plant, though the pledge on the stake may be left.

A few days before the Show decide which plants will be suitable to show, and examine them critically, to decide if they need any attention, perhaps a little more sun to advance them, or a little shade to hold them back. Make sure they are well watered. The night before a show go over them carefully, removing dead foliage, any pips past their best, ensure no livestock, no dirty or marked foliage and that the pot is clean. I have often repotted into a clean pot. Give them a really good watering and let them drain well. Attend to any staking, cotton‑wool etc for transporting. Pack them carefully so they do not knock each other on the way, separating the pots with crumpled newsprint, foam rubber, polystyrene moulds etc. Check and pack a soft brush, a pen, spare plant labels, compost for topping up, a few plastic bags in case someone gives you a spare offset, and most important, the schedule. Study this carefully, decide which classes you can enter, and if there are alternatives you could fill. Your best plants go into single classes, or in a Six, where the competition is fiercest, and although there are separate classes for beginners there is no reason why you should not be bold enough to enter open classes if your plant is good enough. If the class calls for two plants (distinct) try and get them as distinct as possible, not, say, two red gold centres like A. Winifrid and A. Sandwood Bay.

When you get to the venue, find somewhere to put your plants down and report to the Show table, where you will be given a number, pot labels and pot pins. On the label put your number and the name of the plant. This number is the only means of identifying the grower and ensures complete anonymity in judging. It is the plant that is judged, and only the names of the first three winners are revealed. Position the card where it is clearly visible and does not obscure the plant. Now is the time to look over your plant, make sure it is as good as you can make it, and to dress it if you wish. It is not essential, but might give your plant that edge. When you have done your best, place your plant in it's appointed position , go away and forget it. Have a cup of tea and a natter. The time to sweat is while you wait for judging to finish, you might be lucky and get that card. If you loose only you will know.

Raising New Varieties

Auriculas are bred by enthusiasts to an exact formula, and maybe only one in a hundred will be fit for competition on the bench. (Commercially raised seed will very rarely ever produce "show" plants) Two criterion are needed, form to pass the judge's eye, constitution to ensure long life. Only the dedicated enter this field, but it is the most rewarding part of the Fancy. Winning with another person's plant is not half so satisfying as winning with your own.

Primulas come in two forms, pin‑eye and thrum eye, only thrum‑eye are allowed on the Show‑bench, the pin‑eye plant has largely been bred out. To get a new variety, you choose and cross two suitable varieties. Some plants are better seed parents, some seem to be better pollen parents. Mary is a good seed parent, but tends to pass on it's subdued colour. Doubles are more difficult to breed than Alpines, as the inheritance factor or 'gene' disappears in the first seedling generation and only appears in the second. We say it is "recessive" or hidden.

Preparing plants for the show bench Knowle show

Adjusting the petals on a light centred alpine auricuala

Plants on the show bewnch at Midlands show held at Knowle

First you must make sure the pistil or pin, the female part, is receptive to pollen, when the flower is half‑open. Cover it with a cloche while it opens halfway, to keep off bees and other pollen. Its own pollen is not yet ripe, but it is as well to remove its own stamens while you expose the sticky stigma, the knob on the pin. You can either cut off with scissors the top part of the pip, being careful not to cut off the pin, or you can do as I do, tear the petals down and eventually off. In either case you mutilate the flower, but so long as the stigma is not harmed, all will be well. Next make sure the intended pollen parent's pollen sacs are ripe, they should be covered with yellow dust. This has to be placed on the seed parents stigma, with a clean small brush or by contact. Again I tear the petals, on one side now, turn them down and wrap them round to make the stamens stand up proud, when it is an easy matter to touch them gently on the stigma. You can see if the pollen adheres as the pin turns yellow. My way results in two ragged pips, but can be performed with only your fingers and no sterilising the brush in meths and waiting it to dry before trying another combination. It is important to record the cross, on a label stuck in the pot and preferably in a notebook, and also to mark the treated pip with bright wool so you do not pinch it off inadvertently in routine dead‑heading. With no petals the plant is unlikely to be visited by bees, but the plant can be popped under a cloche for a few days to make sure. If the cross takes, the petal remains fall off, the pod swells and the stem remains green. A yellow stem means no seed, or if the pods do swell with seed that the seed is ripe. It must be watched as when ripe the pod opens and the seed can fall out and be lost.

There are two times to sow the seed, as ripe‑ (when germination can be rapid, 4 days is my quickest) or it can be stored in cool dry conditions and sown in early spring, late February or March. Small seedlings are at risk in a cold winter from drying out, so it is best to keep them frost free, watered and growing but both kinds usually flower in their second spring if grown well. Store seed in paper packets in a closed container in the frig; mine go in an old honey jar on the door rack. Don't store seeds in polythene, they go mouldy. Sow on sterilised well‑drained compost, and cover with only a layer of grit, as like all Primula seed they need light to germinate. Do not use heat to hurry them up, they germinate best at about 50F (10C), above 60F(15C) they enter secondary heat‑induced dormancy. Keep the seedlings cool and moist, as drying out is easy and fatal, as I have found to my cost. They can well be covered with a sheet of glass, or a layer of mutton‑cloth or similar, which lets through rain and light but not slugs. They can either be pricked out in trays or pots, I use trays as I know only one or two will be of showable standard in any batch. I like to plant mine in a reserve border in early autumn to weed out the weaklings, as many are 'soft' and will not live long. I lift any probables and show them when their trusses are suitable, usually in their second year. Only if your seedling wins a prize should it be named, and only if it succeeds in open competition should it be 'let out' to other growers. By then it should have more than one offset, and it is a good rule to keep the first offset and give the second to a reliable friend in case you lose your stock. I have had proved more than once 'She that gives shall receive back'

POINTS OF EXCELLENCE

Well balanced crisp healthy foliage.

A strong stem, holding the truss just clear of the foliage.

No less than five well developed pips.

Footstalks long enough to avoid overcrowding, but not so long to admit drooping.

Rounded smooth‑edged petals withour notches or serrations.

Alpines a circular tube, filled with anthers hiding the stigma.

A golden, yellow, cream or white centre, without farina.

A richly coloured edge, shading to a paler tint, not coarse.

The edge of the centre next the coloured edge to be a perfect circle.

The pip to be flat, not cupped or reflexed.

Doubles Colours to be rich or clear, not muddy

Doubling to be symmetrical and fill the corolla effectively.

Doubling to be consistent from the first to the last pip.

Varieties suitable for a new collection

Gold‑centred Light centres

Argus plum

Winifrid dark red

Sandwood Bay "

Applecross "

Valerie lilac

Prince John "

Rowena pink

Bolero "

Mark pink

Rodeo golden brown

Phyllis Douglas purple

Janie Hill "

Adrian lavender

Shergold "

Sandra rose

Merridale "

Sirius buff

Andrea Julie "

Joy dark red

Lisa pink

Doubles

Mary cream

Catherine primrose

Moonstone Yellow

Golden Chautreuse

Pink fondant

Guinea Gold

Susannah lilac

Prima yellow

Plant after division, rootes cleaned and ready for potting

Divisions potted and grown on in the cool shade

Dispaly of Auriculas at the RHS Chelsea Flower Show

The Society

Anyone interested in the cultivation of primulas is advised to join the National Auricula and Primula Society. This is organized in three sections.

Midland Section

The Honorary Secretary, Neil Tyers, 6 St. David's Crescent, Coalville, Leicestershire, LE67 4SS. Telephone: 01530 810522
e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.

Southern Section

Secretary: L.E. Wigley, 67 Warnhnm Court Rosd, Carshanlton Beeches, Surrey. SM5 3ND This email address is being protected from spambots. You need JavaScript enabled to view it.

Northern Section

Secretary : Lisa Peacock - This email address is being protected from spambots. You need JavaScript enabled to view it.

As well as holding shows and other functions, each section issued a Year Book containing articles on the culture of auriculas and hardy primulas. Plant sales are held at the shows and various meeting throughout the year.