The Primula species fits basically into three categories, namely alpine, border, and indoor.
The most common of these species are;
Alpine
allioni
auricula
Border
denticlata
vulgaris
polyanthus
Indoor
malacoides
obconica
allionii;This species forms 50mm high hummocks and spread to around 150mm diameter.
The 25mm wide flowers, one or two to a stem appear in March/April.
Winter dampness may damage the leaves, so it is better to grow in alpine house.
auricula;This species forms clusters of 20mm diameter flowers in umbels from March to may and grows to around 150mm high with a similar sized spread.
denticulata;The Drumstick primrose is a vigorous perennial that is suited to growing in the border, rockery or as a pond marginal plant.
It grows approximately 300mm high and should be planted out at 250mm centres.
It bears numerous 50-75mm globular flowers from March to May
vulgaris;This compact plant grows approximately 150mm high, and should be planted out at 250mm centres. 25mm diameter flowers are produced in March to April.
polyanthus;A hybrid originating from vulgaris and can be used as a border or pot plant.
This compact plant grows approximately 200mm high, and should be planted out at 250mm centres, the clusters of 25mm diameter flowers are produced in March to April.
malacoides;The fairy primrose is a perennial generally grow as an annual.
The whorls of 12mm diameter star like flowers are produced from December to April on slender 400-500mm stems.
obconica;Another perennial that is generally grown as an annual. It grows to around 400mm high and the stems carry clusters of 25mm diameter flowers from December to May.
note;
Some people get a painful allergic action from touching the leaves so it is recommended that gloves be worn when handling this plant.
Cultivation - Indoor species
Plants should be grown initially, in 75-100mm pots then into 125mm pots of JiNo2 (or equivalent) in October.
As the flower stems start to lengthen, give regular weekly high potash liquid feeds.
Keep the plants moist at all times, and at a minimum temperature of 10*C(50*F)
Propagation
Primula seed germinate better when sown when fresh, i.e. after collection usually May to September.
Purchased seed should sown February /March.
Sow the seed on the surface of a tray/pot filled with seed compost, cover with a sheet of glass, or place in a polythene bag and maintain a temperature of 16*C ( 60*F).
Prick out seedlings when large enough to handle into trays/boxes of multi-purpose compost and grow on tilt they are around 50-75 high then pot up into individual 90mm pots of Ji No1 compost (or equivalent).
Later pot up into 150mm diameter pots of Ji No2 (or equivalent).
Cultivation - Outdoor species
These specie require a fertile soil that is not subject to drying out in summer, therefore copious amounts of well rotted manure should be added prior to planting out in October. A dressing of bonemeal spread at a rate of 4oz/sq metre should also be added at this time.
Propagation x Cuttings
Plants can be divided after flowering, and planted directly into their new flowering positions.
Cuttings can be taken from auricula by taking 40-50mm shoots in June-August and inserting in 50-50 mixture of multipurpose compost and sharp sand then placing them in a cold frame. When rooted pot up into 90mm diameter pots of Ji No1 potting compost and grow on in the cold frame till planting out time the following Spring.
Propagation x Seed
Primula seed germinate better when sown when fresh, i.e. after collection usually May to September, sow the seed on the surface of a tray/pot filled with seed compost, and place in a cold frame
Purchased seed should sown February /March. Sow the seed on the surface of a tray/pot filled with seed compost, cover with a sheet of glass, or place in a polythene bag and maintain a temperature of 16*C (60*F).
Prick out seedlings when large enough to handle into trays/boxes of multi-purpose compost and grow on tilt they are around 50-75 high then pot up into individual 90mm pots of Ji No1 compost (or equivalent).
Later pot up into 150mm diameter pots of Ji No2 (or equivalent)