Campanula - Bell-Flowers

Campanula portenschlagiana

Contents

1. Top Tips
2. Location, Water, Humidity & Fertilisation
3. Dormancy Care & Annual Flowers
4. Common Issues
5. Origins, Temperature, Propagation, Repotting & Toxicity.

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Top Tips & Info

• Care Difficulty - Moderate
• Bright, indirect light is best. A splash of winter sunlight for an hour is highly beneficial to counteract the darker days and longer nights.
• Keep the soil evenly moist whilst in flower, using lukewarm water and the bottom-up method of irrigation. Reduce the frequency of irrigations slightly over the autumn and winter months to avert the promotion of root rot. 
• Average room humidity is acceptable for Campanula.
• Supplement fortnightly using a potassium-based feed whilst in bloom, reverting back to a 'Houseplant' fertiliser at monthly intervals.
• Transplant every three years during the spring, using a 'Houseplant' potting mix and the next sized pot.
• Scroll down to the 'Dormancy Care & Annual Flowers' section to learn about annualising blooms.
• Unfortunately, due to the limited lifespan of a Campanula, it's wholly natural for your specimen to die shortly after its final flower has elapsed.

Location & Light - 🔸🔸🔸

We'd recommend situating your specimen in a bright, indirect location while the plant is in bloom. Once the autumn swings around, be sure to relocate the Campanula into a windowsill that offers an hour or two of morning sunlight. A north, north-east or north-west facing-window is perfect for keeping the specimen 'ticking over' throughout the autumn and winter. 

Water - 🔸🔸🔸

Watering-related abuse will quickly lead to an unhappy Campanula, whether that's under, or over-watering. Once the top third of the soil has dried out, rehydrate by using the bottom-up method to reduce the chance of diseases associated with excess moisture on its foliage. Set the plant on a saucer one water around a quarter deep until thorough absorption. Repeat this step weekly, especially with those grown in bright, warm locations. Under-watering symptoms include rapid flower loss and dry, crispy leaves; these issues are usually due to either forgetfulness, too much sunlight or too much heat. Even though under-watering is far better than over-doing it, never allow the soil to thoroughly dry out for too long as this could reduce the chance of new buds forming. Over-watering symptoms include rotting lower leaves, yellowing leaves, a loss of buds or flowers, and root or crown rot. Allow most of the soil to dry out in between waters, and do not allow a pool of standing water accumulate beneath the pot. Scroll down to 'Common Issues' for more information on this. 

Humidity - 🔸🔸🔸

Average room humidity is enough to satisfy this plant, as long as you don't live in an overly-dry climate. Never situate it within a few metres of an operating radiator due to the enriched chance of browning leaf-tips. If you are indeed worried about dry air, create a humidity tray to provide a moist and stable environment for your plant, which will also have the added benefit of slowing the rates of drying soil!

Fertilisation - 🔸

We'd recommend fertilising your specimen once every two to four weeks in the spring and summer, and monthly thereafter using a 'Houseplant' or 'Streptocarpus' labelled feed. A general plant fertiliser is acceptable too, but remember to dilute the solution by half to prevent the burning of roots.

Dormancy Care & Annual Flowers

Provide a bright, and cool autumn and winter period around 15℃  (59℉)  to reinforce its dormancy. Keep the roots pot-bound to add further stress onto the specimen, which in turn will significantly heighten the chance of flowering. Blooms will generally appear in the summer, during the active growth season, but can appear anytime within the months of spring to autumn. Remember - Campanula will only respond with flowers if they are subject to a successful dormant period in the autumn and winter. The following steps should be taken from early autumn until the start of spring. 

Sunlight & Location

Be sure to provide a bright location with little to no direct sunlight. Although the winter rays won't necessarily hurt the plant, be careful not to fall in the trap of sun-scorch and severe dehydration. Avoid deep shade and the use of artificial lighting at night or locations that boast temperatures higher than 18℃  (64℉).

Hydration

Reduce waters so that at least half of the soil becomes dry. It's essential to keep them on the drier side to life, as they'll think that hard times are ahead and therefore will need to pass its genes on to the next generation.

Occasional Feeds

During the autumn and winter, fertilisation should be performed at monthly intervals with a 'houseplant' feed. While the flowers are in development or in bloom, use a Tomato fertiliser to provide fortnightly nourishment of potassium.

Reduce Everything

This is to remind you that everything needs to be reduced - especially the temperature.

Temperature

This is the most significant step; reduce the temperature down by around 5℃ compared to the summertime or place in a room that's between 14º - 17℃  (57º - 62℉).  You'll be at a significant disadvantage if the ambient temperature is kept constant throughout the year, as Campanula will only respond in locations that have daily fluctuations of around 4℃. Never exceed the minimum temperature as it may lead to plant death or yellowed foliage at a bare minimum. If these steps are followed successfully, you could see a show of blooms in the following summer - but remember, dealing with nature may not always provide the results you'd relish.

Common Issues with Campanula

Over-watering is the biggest issue when it comes to Campanula. Typical signs include brown leaves with soft spots on the underside of the leaves, basal rot or Botrytis forming in the centre. Not only do you have to be mindful of root rot, but also have a think about which plant parts to keep dry. Its central crown must also remain dry at all times to prevent the development of bacterial diseases or mildew. For small cases, ease off with the irrigations and improve the light levels. If the plant is wilting despite being sat in moist soil for a long period, root rot has sunk in. Remove the plant from the pot and remove the affected compost and roots with a clean pair of scissors. Place it back in the original container (or a smaller one if there aren't many roots) and ease off with the waters. Do not place in a dark location as this may risk further rot. Click here to learn more about root rot.

If your Campanula develops basal collapse, it may spell the end of its life. The rhizomes, which are located below the soil line and act like a modified stem, is the lifeline for a successful specimen, so any issues of rot will kill it outright. If yours has problems of this, be sure to take the plant out of the pot and inspect its roots. Prune away any rotten areas and check its base for a softened profile. Remove any individual plants that have a rotten bottom and repot the healthy specimens in a fresh batch of 'Houseplant' compost. Provide a brighter location and reduce the number of waters slightly to avoid further rot. Discard the plant if there is no sign of health below the soil line. 

Yellow central leaves are the result of excess moisture settling on the foliage, typically promoted by dark locations. Instead of pouring water directly onto the foliage, irrigate at the soil line by lifting the foliage at the side to prevent wetting the leaves. If symptoms don't improve, cut the Campanula back to an inch above the soil line to promote new growth.

A sudden loss of older flowers with a yellowed stalk is a sign of prolonged droughts. Especially during the flowering process, near-continuous moist soil is mandatory for extended blooms; allow the roots to turn a green-greyish colour in between irrigations.

Short-lived flowers could be the product of low humidity. Place the specimen on a pebble tray, keeping the reservoir topped up with water while the heaters are operating. Never mist the flowers due to the high risk of developing Botrytis Petal Blight.

A lack of flowers is caused by an insufficient dormancy period, where the temperatures are kept more or less the same over the year. Reduce the temperature by a couple of degrees over the autumn and winter months, along with fewer irrigations to ensure a well-spent dormancy. As spring arrives, the natural temperature will begin to increase, with this is being the perfect time to increase waters and fertilisation. Remember, the warmer the summer days are, the more likely a specimen is to reflower.

Curled leaves and dried brown edges are the result of too little water and over-exposure to the sun. Although Campanula can naturally do well in sun-filled locations, those that haven't acclimatised to the harsh rays will show signs of sun-scorch and environmental shock. Gradually increase the amount of light every few days, starting from an indirect location to a few hours of morning/evening sun over a few weeks. Prolonged exposure will significantly speed the process of dehydration, so consider transplantation into a bigger pot in the spring to wrap the roots around moister soil.

Origins

Campanula is a genus of around five hundred species, which include annuals, biennials and perennials. Their distribution is largely in the northern hemisphere and is commonly found in woodlands and grasslands in Europe and North America. The genus was first described back in 1753 by Carl Linnaeus, during a visit to the Americas. Campanula comes from the Latin words for 'little bells' that refer to the shape of the flowers that are developed in across the spring and summer. The most popular indoor species, C. portenschalgiana, was first penned by Josef August Schultes in 1819, honouring the 19th-century Austrian botanist, Franz von Portenschlag-Ledermeyer

The Distribution of Campanula portenschlagiana

Temperature

-2° - 25°C   (28° - 78°F)
H3 (Hardiness Zone 9) - Tolerate to temperatures below freezing. Although it can survive frosts and thin snow, refrain from bringing it indoors overnight if the room temperature is above 5℃ (40℉), as a sudden change in temperature may cause environmental shock with weakened spring growth and a lack of flowers over the season's course. Instead, either leave it outdoors or in an unheated conservatory, brightly lit garage or a greenhouse until the risk of frost has elapsed.

Spread

Up to 1m in height and 0.8m in width. The ultimate height will take between 4 - 6 years to achieve.

Pruning & Maintenance

Remove yellow or dying leaves, and plant debris to encourage better-growing conditions. While pruning, always use clean utensils or shears to reduce the chance of bacterial and fungal diseases. Never cut through yellowed tissue as this may cause further damage in the likes of diseases or bacterial infections. Remember to make clean incisions as too-damaged wounds may shock the plant, causing weakened growth and a decline in health.

Propagation

Via Seed, Basal Cuttings or Division.

For basal cuttings (Moderate), use shoots that have a soft wooded base and haven't flowered. They should be at least 10cm (4 inches) in length and are found in the centre of the plant where the new growth takes place. Remove the lower half of the leaves, dip the wound in some rooting hormone and place in a well-draining potting mix - Seed & Cuttings Compost is advised. While the plantlet is still young, avoid direct sunlight and water-logging and repot once there is at least 2cm of growth.

Division (Moderate) - Split the root ball into several sections during the start of spring. Dividing too-small segments of the rootball could lead to transplant shock or unsuccessful propagation. Segments that are at least 5cm in diameter serve the best chance of propagation due to the stored energy in the roots and stems. Place the sections into houseplant compost and water regularly, avoiding prolonged sunlight and persistent droughts.

Flowers

Campanula will flower between late spring to early autumn when grown correctly. Each individual flower will last up to ten days, with the overall show lasting up to six weeks. Supplement the soil using a fertiliser high in potassium to prolong its flowers - 'Streptocarpus' or 'Tomato' labelled food is an excellent choice.

Repotting

Repot every three years in spring using a 'Houseplant' labelled potting mix and the next sized pot with adequate drainage. Campanula are far better potbound for several years due to the heightened risk of root rot and repotting-issues (like transplant shock), so only repot if you feel it's wholly necessary - restricted root growth will also increase the chance of blooms, too.

Hydrate the plant 24hrs before the tinkering with the roots to prevent the risk of transplant shock. For those situated in a darker location, introduce an extra amount of perlite and grit into the deeper portion of the pot to downplay over-watering risks. Click on this link for a detailed step-by-step guide on transplantation, or via this link to learn about repotting with root rot.

Pests & Diseases

Keep an eye out for mealybugs, aphids, fungus gnats & root mealybugs that'll locate themselves in the cubbyholes and undersides of the leaves, with the exception of the latter in soil. Common diseases associated with Campanula are root rot, leaf-spot disease, Botrytis, rust, powdery mildew & southern blight - click here to learn more about these issues.

Toxicity

Not known to be poisonous when consumed by pets and humans. If large quantities are eaten, it may result in vomiting, nausea and a loss of appetite.

Retail Locations

Some florists & online stores may sell Campanula during the spring and summer, along with garden centres stocking them outdoors. It's not advised to bring outdoor plants inside as this could lead to environmental shock and the risk of introducing pests into the home. Have a search online for potential purchases.

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