Reviewed By ROY NICOL
Roy is a Professional Gardener and Horticultural Consultant, specialising in large garden year-round maintenance and garden development. He is an RHS Master of Horticulture and uses his research in the application of no-dig methods in ornamental garden settings. Roy has been a Professional Gardener for more than six years and is a member of the Chartered Institute of Horticulture, Professional Gardener's Guild and Association of Professional Landscapers (Professional Gardener).
Want to brighten up your garden with a flower that melds the cute with the exotic?
Calceolaria, also known as the slipper flower, will do it in spades.
This tender shrub produces incredibly charming little blooms that resemble a lady’s purse (another popular name for them) in warm hues.
Overview
| Botanical Name | Calceolaria integrifolia |
| Common Name(s) | Slipper Flower / Slipperwort / Pocketbook Plant / Lady’s Purse |
| Plant Type | Perennial Sub-Shrub |
| Native Area | Mexico, Chile & Argentina |
| Hardiness Rating | H2 |
| Foliage | Evergreen |
| Flowers | Ovoid, 1-1.2cm, shaped like a Dutch slipper, clog, or a lady’s purse; in shades of yellow, orange, and red |
| When To Sow | May to July |
Sunlight
Preferred
Full Sun or Partial Shade
Exposure
Sheltered
Size
Height
0.2 – 1M
Spread
0.1 – 0.5M
Bloom Time
June to September
Soil
Preferred
Most soil types
Moisture
Well-drained
pH
Acidic
Some Calceolaria species and their cultivars produce flowers that are not only cute but have an exotic feel.
Appearing in rich, warm hues, these ovoid flowers look rather like handbags or Dutch clogs, so it’s for good reason that this plant also goes by names like lady’s purse and slipperwort.
Unfortunately, there’s a drawback with growing this plant, as it hails from South America, so is not exactly easy to grow in the British Isles.1Calceolaria. (n.d.). Plants of the World Online. Retrieved August 3, 2023, from https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:331444-2
Also, when planted in open ground as a bedding plant, it will effectively be an annual in the UK and Europe because it is so tender.
Common Types
While the species plant, Calceolaria integrifolia, has received the RHS’s Award of Garden Merit, the ‘Sunset Mixed’ cultivar features delightful colours and has a very long flowering season.
The species plant, if grown as a perennial, will eventually approach 1m in height. For 2-3 months over spring and summer, it produces flowers in a bright, sunny yellow tone.
‘Sunset Mixed’ grows to only 20cm tall, but it produces flowers in glorious yellows, oranges and reds, some with markings, streaks and splashes across its petals.
With some luck, it will bloom from sometime in April to July.
How To Grow Calceolaria
Soil Requirements
Slipper flower requires light, friable, moderately fertile soil that drains very well and is somewhat acidic.
A sandy loam mixed with grit, perlite or both will make a very good base.
Minimise chalk and clay as components.
The best soil pH for this plant is acidic.
Placement
Although this evergreen sub-shrub is often grown as bedding and for borders, doing so in temperate regions such as the UK effectively turns it into an annual.
I suggest that you grow this unusual sub-shrub in a container so that you can try to enjoy its special charms year after year.
After the weather has warmed up in late spring, take the pot outdoors and position it somewhere it only gets dappled or filtered sunlight.
A sheltered spot with an east or west-facing aspect is best.
This plant thrives in a fairly narrow temperature range of 15-19°C and also prefers humid environments.
In mid-autumn, you can shift it indoors.
Sowing
If you attempt to grow a lady’s purse from seed, I recommend that you obtain seed packets from a trusted nursery or seed company.
Seeds collected by hobbyist gardeners, even from a species plant, may not be viable and can be difficult to germinate.
- Sow seeds between April and July.
- Temperatures between 17-20°C will greatly aid in germination.
- In small pots, sow seeds onto the surface of a seed-starting or potting mix with added sand.
- Moisten the medium.
- If sowing in April or May, put the pots in a cold frame outdoors and if sowing in June or July, cover the pot with a clear polythene sheet that has a few punctures.
In either case, choose a position which gets ample dappled or filtered sunlight.
Planting
If you transplant Calceolarias into open ground, do so a couple of weeks after the last frost only if the weather and the soil have warmed up.
You should be able to plant out in most UK locations from late May.
Choose a sheltered spot that gets dappled or filtered sunlight, preferably with an east or west-facing aspect.
Calceolaria Plant Care
Watering & Fertilising
Watering Calceolaria is a bit of a balancing act.
Underwatering will be signalled by drooping foliage, but overwatering will not be signalled in good time and it may cause root or crown rot.
So, while the plants require ample water, you cannot run the risk of overwatering, especially in summer.
To strike the correct balance, water generously, then allow all of the soil to fully dry out before watering again.
For outdoor plants during a hot, dry summer, water daily, whilst during temperate, humid weather, let the foliage be your guide!
From early May until the end of the blooming season you can feed fortnightly with a very diluted solution of high-potash fertiliser.
For slipper flowers, dilute the fertiliser to only 25% of the strength and also apply by half of the recommended volume.
Deadheading
Deadheading will stimulate fresh blooms and prolong flowering, so you may pinch off single spent blooms.
However, when most of the flowers in a cluster are withered, snip off the cluster itself with a pair of sterilised secateurs.
Collecting Seeds
If you want to collect seeds, you will need to let the flowers stay on the shrub so that they form seed pods.
After the seed pods are fully formed, you can remove them in late autumn.
They can be opened with thumbs and fingers to expose the seeds.
Be aware that only the seeds from the species plant will give you a chance to germinate new plants from seed.
Collecting seeds from plants that are crosses or cultivars will likely be an exercise in futility.
Propagation
Propagating slipper flowers is a tough ask, especially in the UK.
To propagate by cuttings, the best time period is July to August, during which you should take softwood cuttings.
Cut just beneath a node.
Insert the cutting into a well-draining mix of sand and potting compost in small pots and moisten daily.
Keep the pots indoors near a window where they get the maximum amount of indirect light but no direct sunlight.
Common Problems
The most serious problems that may affect Calceolarias are root rot, crown rot and grey mould.
The first two problems are caused by human error and are preventable by balancing the watering as described above.
The third is a fungal disease that typically strikes when a plant is indoors or in a greenhouse in humid conditions.
Though it is easy to spot in its early stages, no chemical controls are available to hobbyist gardeners.
Grey mould can often be prevented by ensuring adequate ventilation and not overcrowding plants.
Other than that, these plants may be attacked by aphids, slugs and snails.
