Calibrachoa – Superbells® Cardinal Star
Dead-Heading Not Necessary
When planting Calibrachoa I often give the plants a slight trim, using a sharp pair of scissors or pruning shears. While not a necessary step, it will increase branching and may help your plants look even fuller.
Calibrachoa are usually easiest to grow in containers because if the roots are kept too wet can lead to root rot diseases. In containers, allow the top of the soil to dry before watering again. If your plant is wilting even though the soil is still damp you likely have a root rot problem. Calibrachoa can be fantastic in-ground plants, but only if they are planted in well drained soil. Raised beds would be a good choice for planting Calibrachoa in the landscape. In the ground they shouldn't need much additional water unless conditions are very dry. Proper watering is key to growing good Calibrachoa.
The plants are low-maintenance with no deadheading needed. They will do best if fertilized in a regular basis. Calibrachoa can be sensitive to both high and low pH. If your plants have been growing for a while and then begin to look a bit tired and not so good there are several things to try. If the foliage is yellow there are two possible causes. If you haven't been fertilizing regularly they could simply be hungry and in need of fertilizer. Feed them using a well-balanced (look for something with an n-p-k ration near 20-10-20) water soluble fertilizer. If you have been fertilizing regularly with a well-balanced fertilizer and the foliage is still turning yellow it is probably because the pH range in your soil has gotten a bit high or low. The most common impact of this is that Iron can no longer be taken up by the plant, even if it is available in the soil. The common form of Iron used in fertilizer is sensitive to pH changes. If you think pH is your problem you can either try to lower (or raise) the pH or you can simply apply Chelated Iron, which is available at a wider pH range and should help your plants turn green again. You may also be able to find Iron in a foliar spray (which means you spray it on the foliage rather than applying it to the soil) which can also help your plant turn nice and green again. Stop by your favorite garden center and they should be able to help you choose a product to use.
As the season goes on the plants can sometimes just start to look open and not as good. This can happen even if they are being watered and fertilized correctly. Fortunately this is very simple to fix. Grab a sharp pair of scissors or pruning shears and give the plants an all over trim. This will cause them to branch out more and should stimulate new growth and flowering, especially if you fertilize right after trimming them back. Just like your hair looks a lot better after a trim, your plants often will too. You will sacrifice flowers for a few days, but the plants should come back flowering more than ever shortly. I will usually give my Superbells a trim back in late July or early August. Should your plants have a few unruly stems that are longer than everything else or sticking our oddly, you can trim these stems back at anytime. Calibrachoa are very forgiving when it comes to trimming.
An application of fertilizer or compost on garden beds and regular fertilization of plants in pots will help ensure the best possible performance.
Needs Good Drainage
Calibrachoa don't like to have constantly damp soil. They will do well in the ground only with good drainage. For most gardeners containers are the best use for Calibrachoa.
Maintenance Category Easy
Water Category Average
Flower Form Container
Soil Fertility Average Soil
pH A - pH 5.5 - 5.8
EC (2:1 Extraction Method) 0.6 - 0.9
Fertilization 150 - 200
Light Requirements High
Water Requirements Moderate to Moist
Rooting Out Temperature 65 - 72° Fahrenheit
Growing On Temperature 55 - 65° Fahrenheit
Holding Temperature 40 - 50° Fahrenheit
Planting and Timing Information
Early Spring through Fall Finish. Standard PPP.
Finishing Times [weeks]
4-5" and Quart Pot : 4-6
6" and Gallon Pot : 5-7
7-9" Pot : 7-9
10-12" and Two Gallon Pot : 10-12
Pinching and Growth Regulators
For all sizes of containers, pinch the liner 1–2 weeks after transplant; for containers larger than 6” and for hanging baskets, trim around the edge of the container as needed prior to spacing or hanging of the baskets. 5-10 ppm Sumagic or a B-9/Cycocel (2500/750) tank mix is effective. Red and Yellow Chiffon are very responsive to PGRs so lower rates should be used. 500 ppm Florel on baskets and larger pots will promote branching.
Pest and Disease Management
General pest and disease practices as listed in notes. Calibrachoa are sensitive to pythium, phytopthera, and thelaviopsis. Superbells have higher levels of tolerance to these diseases than other Calibrachoa, however, maintaining proper pH (5.5-5.8) and good sanitation practices will help alleviate problems. Increased air circulation, proper water management and good soil porosity are also critical. Scout regularly for aphids which can be problematic. Be sure to check hanging baskets that are hanging high, it can be easy to forget to scout for insect problems with pots high in the rafters. When selecting Supberbells we screen for disease resistance to Thielaviopsis; Pythium and Phytophthora.
Preventive fungicides are recommended two weeks after transplant. It is strongly suggested that growers use caution when using Medallion due to the potential leaf spotting in Calibrachoa. -Requires high light in production. -Needs 200 ppm fertilizer for optimal growth. -The Superbells series is constantly evaluated for pH sensitivity, this is considered a major issue for the crop, so all trialing evaluates response to high pH and selects away from sensitive clones. It is still best to keep pH below 6.0. -'Red' and Yellow Chiffon are very responsive to PGR's, so lower rates should be used. -Cold is a good natural growth regulator. -Yellow growing tips is often an indicator of high pH. -Blackberry Punch and Lemon Slice is more sensitive to rooting issues, water management is critical. -Superbells Blue, Superbells Scarlet, Superbells Blackberry Punch and Superbells Dreamsicle can be more upright, especially in lower light conditions. They may need extra pinching and PGR's to control growth. -Superbells Apricot Punch is very early to bloom, you may want to remove some initial flowers to promote plant growth.