Back in the 1700s, geranium was split into two separate groups.
Pelargoniums currently include 280 species and are the most common geraniums in gardens.
Preferring warmer temperatures, pelargoniums are divided into several different groups.
Meanwhile, the actual geranium genus has 400+ species and is able to thrive in more temperate regions, earning them the nickname of “hardy geraniums”.
Of course, there are other differences between the two genera than just preferred hardiness zones, but they also still have a lot in common.
Known for robust blooms, geraniums can be easy to care for, but what happens when those show-stopping flowers fail to appear?
The causes are usually the same and easily fixed, although each genus has its own particular quirks.
More on the Types of Geraniums and Pelargoniums
Why is My Geranium Not Blooming?
While it may feel like the end of the world, your geranium’s failure to bloom is likely due to a fairly simple care issue.
The following are some of the most common reasons for bloom failures, as well as how to solve them.
Dividing Time (Hardy Geraniums)
Unlike pelargoniums, division is a necessary part of a true geranium’s life.
Once it reaches a certain age, the root structure can become so large that the plant has trouble getting all the nutrients it needs.
This problem usually begins to present itself when the plant is a few years old and may be accompanied by smaller leaves and a much wider growth habit.
Solving this problem is incredibly easy – simply divide the plant in spring.
Not only will this help resolve the problem, but it will also give you two or more happy geraniums for the price of one.
One mistake a lot of growers make is to stick to a single fertilizer mix at all times.
While generally not a problem, this can lead to some issues with heavy bloomers such as geraniums.
A good balanced fertilizer combined with a water soluble fertilizer is perfect for early spring. But, you may want to switch to a mix with half as much nitrogen once blooming starts.
This is because nitrogen is used to promote healthy growth of stems and foliage, while phosphorus is needed for bloom production and potassium is needed for a plant’s overall health.
By providing too much nitrogen, the plant will continue to focus on new growth, pulling resources away from the blooming process.
Cutting back on how often you fertilize or adjusting the mix when the plant begins to bloom can help with this issue.
Geraniums need plenty of light, and even the hardiest will want 4 to 6 hours minimum of sunlight.
Morning or evening exposure tends to work best. Indoor geranium plants may also need more than a sunny window, with a little augmentation from a grow lamp or other artificial source.
The source of so many plant woes is too much water. Overwatering geraniums can lead to root rot, a deadly disease that destroys a plant’s ability to absorb water and nutrients from the soil.
You can check for overwatering by looking to see if the lower leaves are red or yellow.
Alternatively, sticking your finger in the soil can not only tell you if it’s overwatered but also when it’s thirsty.
All geraniums will need to be watered when the soil is dry 1” inch down using the soak-and-dry method. Always use a pot with drainage holes and soil with good drainage.
However, if the soil feels soggy or wet, avoid watering until it dries out some and consider checking the soil quality.
Geraniums can be heavy feeders, so they tend to fare best in loamy soil with a bit of sandiness for drainage.
Using organic compost and mixing in some coarse sand or perlite can really work wonders for both indoor and outdoor plants.
Not only will the organic matter provide vital nutrients and help replenish leeched nitrogen, but it increases the soil acidity and can even retain a little water during dry spells.
Meanwhile, an aggregate such as perlite will prevent the soil from becoming too compact and improve drainage.
Pelargoniums are more sensitive to cold than hardy geraniums, but that’s not to say they both don’t like a similar temperature range.
Geraniums can have difficulty blooming if the temperature gets outside the range of 60° to 85° degrees Fahrenheit.
Ideally, hardy geraniums prefer slightly warmer temperatures of 70° to 75° degrees Fahrenheit during the day and 60° to 65° degrees Fahrenheit at night, with pelargoniums liking it about 5° degrees Fahrenheit warmer.
You can help protect your outdoor geranium from falling out of these ranges by providing a little noon shade or mulching to keep the roots warmer.
Tips for Better Blooms
Even if your plant is blooming, it might not be as prolific as you’d like.
A lot of gardeners recommend cutting the plant back after the first bloom of the year to encourage new, healthier growth and a potentially bigger show later that summer.
If you don’t wish to do this, however, you can deadhead spent flowers.
This will increase the amount of resources the plant can devote to new blooms.
Finally, trim away any leggy sections and watch out for any geranium plant pests or fungal diseases which might reduce the plant’s ability to bloom.