Their delicate and exotic blooms mean that some botany novices will mistake them for being an unusual type of orchid. There are over 300 different species in this genus, but the ones that tend to be available commercially are cultivated, tender, herbaceous perennial hybrids that are sold as annuals. They generally have showstopping bright yellow and orange blooms, sometimes with red spots. Calceolaria usually last for just the one season before they’ll have to be replaced as they rarely rebloom. These flowers prefer a cool and not overly bright location and are mostly sold for display indoors. In the right conditions, they’re sometimes also planted outdoors as seasonal bedding plants. They aren’t tall flowers, so you’ll need to make sure they won’t be overshadowed by other species planted alongside them. The potted plants tend to be available for sale in the U.S. through the winter and early spring. Calceolaria species aren’t the easiest plants to care for. They’ll need the right conditions and careful nurturing if you want to maximize their bloom period. If they get this, the plant could stay in flower for several weeks.
How to Grow Calceolaria
Although they can sometimes be used as bedding plants, Calceolaria are usually grown in pots indoors. They prefer to be positioned in a cool room with diffused sunlight. They should be watered regularly, and their potting medium should be light and fertile.
Light
This species will thrive in a bright, northern window which receives dappled, rather than direct, sunlight. Avoid southern aspects unless you can filter harsh rays. Conversely, too much shade will generally result in a shortened bloom period, and the petals may wilt.
Soil
Your Calceolaria will grow best in a well-drained and loose potting medium. Make sure whatever pot you use has good drainage. If you’re planting out Calceolaria in flower beds, enriching the soil with compost or peat moss can help to extend the bloom period.
Water
It’s all about getting the balance right when it comes to watering your Calceolaria. Overwatering can play havoc with the plant’s roots, but it’ll suffer from serious wilting and petal drop if it’s left to get too dry. Generously water the plant when the top layer of potting mix is dry to the touch. Make sure you water directly into the medium. If you water over the crown of your Calceolaria the leaves can suffer from gray rot.
Temperature and Humidity
As well as getting the watering right, to maximize the life of your Calceolaria, it needs the right temperatures too. They enjoy cool spring temperatures - excessive heat will kill the plant off quickly. Although they enjoy mild temperatures, they’re very frost tender too. If you’re planting them out as a spring bedding plant, make sure the last of the frosts have passed first. Ideally, daytime temperatures should be around 55 to 60°F to maintain a successful bloom period. Much higher than this and the blooms will quickly die off. These plants also enjoy high humidity. If you’re misting to help increase the humidity indoors, make sure you don’t spray directly on the plant. This can result in gray rot forming on the foliage. Although Calceolaria likes fresh air, make sure it isn’t positioned in a draughty spot.
Fertilizer
To maximize the length of the bloom period with Calceolaria, feeding with a weak solution of a balanced fertilizer once a week could be beneficial. With a short-lived species like this, it isn’t a necessity, though.
Propagating Calceolaria
Summer propagation of Calceolaria should only be attempted by the most dedicated of enthusiasts as it’s very challenging. Even if you purchase a perennial variety, the cutting often won’t make it through the winter.
Varieties of Calceolaria
Two of the most well-known original Calceolaria species are:
Calceolaria uniflora, discovered by Darwin, is one of the most famous original species, but it’s rarely available, and seeds sold under this name are often mislabelled.Calceolaria integrifolia, another popular original species, has seeds that are easier to come by. This is one of the taller and hardier varieties that is sometimes sold as a bedding plant.
Although there are over 300 Calceolaria species, only a limited set of cultivated hybrids are usually sold commercially. Look out for the following names as these are all popular options: Aida, Sunset and Golden Rain.
Pruning
Removing wilting leaves, old stems and spent flower heads can help to encourage the plant to stay in bloom for as long as possible.
Growing From Seeds
Bringing an already potted plant home is much more common and a heck of a lot easier than trying to grow Calceolaria from seed. Given they usually only last for one season, going to the effort of seed propagation will only appeal to the most passionate species enthusiasts. You should also be aware that seeds grown from a mother plant won’t replicate their bloom, and they might not even produce any impressive flowers at all. Sowing is possible from around June or July to October. The germinating seeds need warm temperatures, plenty of light, and they shouldn’t be covered. After germination, the seedlings need consistent, very light moisture; otherwise, they can suffer from damping-off fungus problems. Make sure, however, that you don’t let the soil dry out either.
