Keeping pests and diseases at bay when it comes to houseplants can prove to be a challenge even for the most experienced of us.
Luckily, scented geraniums aren’t as prone to pest infestations and diseases as most houseplants, yet there are a few problems you should keep an eye on.
Besides pest problems, leaf problems caused by fungi and inadequate conditions can also occur, but these too are usually manageable with the right treatment.
I’m going to discuss all the possible issues — be that a pest problem or something else — you may come across when growing scented geraniums in your home or outdoors. I’m also going to offer solutions to treat, and more importantly, to prevent such issues.
Scented geraniums have a reputation of being bug and pest repellents, but there are a few pests that even scented geraniums can’t repeal:
Aphids are small pests the size of a pinhead that feed on the sap of geranium leaves. Aphids usually hang out on the underside of geranium leaves.
They vary in color and leave behind a sugary substance that can gather dirt and debris, causing brown spots on the leaves.
Where there are aphids, there are also ants. Ants are attracted by the sugary substance that aphids leave behind.
Treatment for an aphid infestation includes insecticidal soaps that coat the bodies of these insects and suffocate them, neem oil, or using natural predators like ladybugs that feed on aphids.
To prevent aphids, keep the leaves of your geraniums free of debris, plants with a strong smell like oregano, basil, etc. and use insecticidal soaps or neem oil even preventatively.
Slugs and snails rarely affect geraniums because they tend to feed on debris and rotting leaves instead. But when not available, they’ll take a liking to geranium leaves too if they must.
Slugs will eat geranium leaves from the edges inward, so shredded leaves on your scented geraniums are usually a sign of a slug infestation.
The easiest way to remove slugs from your geraniums is by hand. But might not be lucky to find them unless you search for them at night when they’re most active.
You can also use crushed eggshells around your geraniums planted in the garden. The eggshells will irritate the soft bodies of slugs and keep them away. Sharp sand, sawdust and diatomaceous earth will also help.
To prevent slugs, avoid using mulch in your garden because any decaying matter will attract slugs.
As common outdoor pests, cankerworms are caterpillar-like pests that will feed on scented geranium leaves causing tiny holes on them. Sometimes they feed until only the veins of the leaves remain.
They’re attracted to your property by certain types of trees like oak, maple, ash, black cherry, or basswood.
Using sticky adhesives to trap them, insecticides and manually removing them can help you control a potential infestation.
– Green Fly
Green flies are common pests that behave much the same as aphids. They’ll suck on the sap of scented geraniums and occur in clusters, so they’re easy to identify.
They’re not always green, sometimes they’re yellow, blue-green or pink-brown. They can also be wingless.
The leaves on geraniums infested with green fly can become distorted, bloom can become damaged or even fall off.
Treatment options are the same as in the case of aphids — insecticidal soaps, neem oil, and biological control.
Budworms are the larvae of a moth that lays eggs on buds or ends of new growths of flowering plants. The larvae feed on developing buds or even on the leaves of scented geraniums.
They hang out on the underside of leaves making them difficult to identify because they’re the same color as the leaf. They’re easier to identify as they mature when they get brown heads and black hairs on their body.
Because they emerge from the ground, it’s advisable to change the potting medium of your scented geraniums. Remove budworms by hand or remove sections that are affected by them.
Geraniums can be affected by a few fungal diseases that can cause rotting or damage flowers and flower buds. Environmental circumstances can favor these diseases.
– Stem & Crown Rot
Caused by a soil-borne fungus, stem and crown rot happens often in very hot weather or when the plant is watered excessively after drying out.
A good watering regimen and planting geraniums in sterile soil can help reduce the occurrence of this disease.
Using well-draining potting media and repotting scented geraniums can also help keep this problem under check.
– Flower Blight
Caused by a fungus, the first sign of flower blight disease is the premature drying and fading of flowers. Your scented geranium flowers will turn brown and fall off prematurely.
The disease is most likely to occur in periods with high moisture. Dead flowers can be covered with a gray, fuzzy mass.
Improving air circulation or ventilation, avoiding watering from above, and using clean, sanitized blades when pruning are some of the easiest ways to prevent the disease.
Once it takes a hold of your geraniums, make sure to remove diseased sections and spray with a fungicide to stop it from spreading further.
The fungus that causes flower blight can also damage leaves, causing lesions that are either V-shaped or in concentric rings.
The prevention methods and treatment methods applicable for flower blight will work against leaf botrytis as well.
With fungal diseases it’s important to stop the spread once they’ve already appeared on your plants. Removing affected sections of the plant and discarding them is one of the most effective ways to achieve that.
Oedema is most common on ivy geraniums. It’s thought to be a water imbalance issue that occurs when the weather is cool, cloudy and the air is moist, while the soil is moist and warm.
It’s identifiable from the water-soaked blisters that appear on the underside of leaves. With time, these become rusty-brown and callous over. The leaves can turn yellow and fall off.
Good air circulation, moisture management and a well-draining potting medium can help reduce the incidence of the disease. Proper nutrient levels from correctly feeding scented geraniums can also help.
Other leaf problems in scented geraniums can be caused by various fungi, pests, fertilizing problems, dehydration or overhydration, and lack of light.
Because it’s not always obvious what causes certain leaf problems, ideally, you should take a holistic approach and examine all the various contributing factors including the plant’s care requirements.
Here are the most common leaf problems in scented geranium plants:
– Yellow Leaves
Yellow leaves can signal a number of issues including over fertilizing, lack of enough light, excess watering that rots the roots, or changes in temperature.
Yellow leaves won’t revert back to their green color even though you change the environment of the plant. You’ll know the problem is fixed if the newly emerging leaves no longer turn yellow.
Usually, fading leaves are a sign that scented geraniums aren’t getting enough light, so start with that and work your way through the potential issues one-by-one, until you manage to narrow down the culprit.
– Brown & Crispy Leaves
Brown and crispy leaves on scented geraniums can also be caused by several things such as sunburn, dehydration, or a fungal leaf disease.
Sometimes a pH imbalance of the soil (usually a highly acidic soil), iron or manganese toxicity, a fertilizing problem or a fungal leaf disease problem can also cause brown and crispy leaves.
– Holes in Leaves
Holes in scented geranium leaves almost always indicate a pest or bug problem. Various types of caterpillars can chew holes into the leaves of your scented geraniums.
While scented geraniums aren’t a favorite of certain pests, budworms and cankerworms do take a liking to it.
Removing these pests manually and destroying them can help deal with the issue. In their larval stage they can be destroyed by broad spectrum insecticides, although these can have harmful effects on otherwise beneficial insects.
– Leggy Plants
If your scented geranium grows leggy, the issue is almost always caused by lack of sun exposure. In struggling to reach the light, your scented geranium will grow taller and leggy.
Move your geranium to a location with direct sunlight. For best growth, it should receive around 6 hours of direct sunlight per day.
You can reduce the size of a leggy scented geranium by cutting back leggy growths to stimulate a bushier growth pattern.
Just because I listed so many potential problems with scented geranium plants, it doesn’t mean that you will experience any of these issues. But it’s better to be prepared for when you do.
Knowing how to identify a pest problem early on or how to tell if your scented geranium is getting enough light, water and nutrients can help you better manage its development and potentially save it from damage or an early demise.
Hopefully, the treatment options and preventative measures I discussed in reference to each disease or problem will help you manage any issue that comes along.