Long summer days are made for the outdoors, and so much of the season moves out to porches, patios, gardens, and backyards. Scent is woven through all of it, and a handful of essential oils have a long history in warm-weather and outdoor settings, from citronella torches on the patio to cedar tucked into closets and herb gardens planted by the door.
Below we walk through eight of those seasonal favorites, what each one smells like, and the heritage behind it. We have also gathered what published research has found about several of these oils and insects, reported straight from the studies, followed by three simple diffuser blends for your home and outdoor spaces.
A note on use: essential oils are concentrated. Diffuse in a well-ventilated room, keep them out of reach of children and pets, and dilute properly and patch test before any topical use.
Eight Summer-Favorite Essential Oils
1. Rosemary
Salvia rosmarinus Rosemary essential oil has a fresh, green, herbaceous aroma with a clean woody edge. It smells like a sunlit herb garden and has been a fixture of kitchen gardens and household traditions for centuries. It has been reported to repel insects, especially mosquitos, making it great for keeping them at bay during waterside activities. It also has anti-inflammatory and antimicrobial properties to help relieve bug bite pain and swelling and prevent infection.
2. Citronella
Cymbopogon nardus Citronella essential oil is the scent most of us picture on a summer evening outdoors. Lemony, fresh, and grassy, it has been a staple of warm-weather candles, torches, and patio gatherings for generations. It has been reported to keep away insects by working to mask the scents that attract bugs to us while leaving a lemony fresh aroma for us to enjoy.
3. Lavender
Lavandula angustifolia Lavender essential oil is a soft, floral-herbaceous favorite loved the world over. Its calming, familiar scent makes it one of the most versatile oils you can keep on hand. It has been reported to ward off many insects. It may also help to minimize swelling and speed up healing on insect bites and stings.
4. Peppermint
Mentha × piperita Peppermint essential oil brings a cool, crisp, invigorating aroma that feels especially welcome on a hot afternoon, adding a fresh minty lift to any blend. It has been reported to have insect repelling properties and is especially effective for keeping away home pests like ants and spiders. Peppermint may also provide cooling relief to itchy and irritated bug bites.
5. Cedarwood
Juniperus virginiana Cedarwood essential oil has a warm, woody, grounding scent reminiscent of a walk through the forest. Cedar has been tucked into chests and closets among stored linens for generations, valued for the rich aroma it leaves behind. It has been reported to keep insects at bay. It may also assist with stored items such as clothing and linens from damaging moths as well as repelling pesky bugs from our gardens.
6. Cinnamon
Cinnamomum Cinnamon essential oil offers a warm, spicy, aromatic scent with genuine depth. A long-loved spice across cultures and seasons, it adds a cozy, grounding character to a blend. A little goes a long way. It has been reported to keep many bugs away, including wasps and spiders. It may also have the potential to kill mosquito larvae as a preventative form of pest control.
7. Tea Tree
Melaleuca alternifolia Tea tree essential oil has a crisp, fresh, green aroma with a brisk, clean character. Native to Australia, it brings a sharp, herbaceous note to fresh summer blends. It is well known for its antifungal, antibacterial, and antimicrobial properties that make it great for keeping bug bites clean and preventing infection. It may also work as a good natural insect repellent and insecticide.
8. Chamomile
Roman Chamomile, Chamaemelum nobile Chamomile essential oil carries a soft, sweet, apple-like floral aroma. Gentle and calming, it has a long history in herbal traditions and makes a mellow counterpoint to sharper green and citrus notes. It has been reported to have an anti-inflammatory effect on the skin that may make it great for soothing swollen and irritated insect bites.
What the Research Says
Researchers have studied a number of plant essential oils for how they interact with insects. A frequently cited starting point is a 2005 study in Phytotherapy Research, which screened 38 essential oils against Aedes aegypti mosquitoes in laboratory conditions and found that, undiluted, citronella was among the most effective of the oils tested (Trongtokit et al., 2005). Here is what published work has found on three of the oils above. These are summaries of the research, not claims about any particular product.
Citronella. Beyond the comparative study above, a 2011 systematic review in Tropical Medicine & International Health looked at controlled laboratory experiments on citronella and concluded it can provide protection against mosquito bites, though the effect tends to be short-lived because the oil is volatile and evaporates quickly, with higher concentrations and certain formulations extending the duration (Kongkaew et al., 2011). A separate study testing citronella in candle and diffuser form reported that it repelled significantly more mosquitoes than an untreated control, and that a continuous-release diffuser was more effective than a candle (Müller et al., 2011).
Cedarwood. A 2014 study in Environmental Entomology examined cedarwood oil from Eastern red cedar, Juniperus virginiana, the same species used in our Virginia cedarwood oil. In outdoor and laboratory bioassays, the oil significantly repelled ants, and its main component, cedrol, was toxic to black-legged tick nymphs at the concentrations tested (Eller et al., 2014).
Peppermint. A 2011 study evaluating peppermint oil against Aedes aegypti found that, applied to skin in a laboratory test, it provided complete protection from bites for about two and a half hours before its effect declined, and that the oil also acted on mosquito larvae in water (Kumar et al., 2011).
A few things worth keeping in mind when reading this research: most of these studies were conducted in laboratory settings, often used undiluted or high-concentration oil, and generally found that botanical oils offer shorter protection than conventional products. Essential oils are not EPA-registered insect repellents, so for reliable protection from mosquitoes, ticks, and other biting insects, choose a product made and labeled for that purpose and follow its directions.
These statements have not been evaluated by the Food and Drug Administration. This content is provided for educational purposes only and is not intended to diagnose, treat, cure, or prevent any disease.
Three Outdoor Diffuser Blends
Each recipe is formulated for a 200ml ultrasonic diffuser. Add water up to the fill line, add the drops, and adjust to match the size of your diffuser and your scent preference. Diffuse on a covered porch or near open doors and windows where the air moves.
Porch & Patio
A bright, green blend with citronella, peppermint, and lavender to help keep bugs away while you enjoy warm evenings outdoors.
- 4 drops Citronella
- 3 drops Peppermint
- 3 drops Lavender
Herb Garden
A crisp, herbaceous blend of rosemary, citronella, and tea tree to help keep insects at bay around the garden and patio.
- 4 drops Rosemary
- 3 drops Citronella
- 2 drops Tea Tree
Backyard Evening
A grounding, woody blend with cedarwood and lavender to help keep bugs off on cooler summer nights outside.
Bug Bite Soother Roll On
Quick relief from the pain and itching of a bug bite is important during summer so we can fully enjoy all of our favorite outdoor activities. A handy roll on remedy with lavender, tea tree, and chamomile essential oils will help to soothe pain and itchiness while easing redness and swelling.
Ingredients
- 1 10ml Amber Roll On Bottle
- ⅓ oz Fractionated Coconut Oil
- 5 drops Lavender essential oil
- 5 drops Tea tree essential oil
- 5 drops Chamomile essential oil
Instructions
Add all the ingredients to the roll on bottle and shake well to combine. Roll on to insect bites and stings to combat pain and reduce inflammation.
Frequently Asked Questions
Which essential oils have been studied for use against insects?
Citronella is one of the most studied, alongside cedarwood and peppermint. Published research has examined all three in laboratory settings, with findings summarized in the research section above. Keep in mind these studies often used undiluted oil and measured shorter protection than conventional products.
Why is citronella so associated with summer evenings outdoors?
Citronella has a fresh, lemony, grassy aroma that has been used in outdoor candles, torches, and patio products for generations, which is why the scent feels so tied to warm summer nights.
Are essential oils a replacement for insect repellent?
No. Essential oils are not EPA-registered insect repellents. For protection from biting insects, choose a product made and labeled for that purpose. The oils and blends here are chosen for their scent and the outdoor atmosphere they create.
What essential oils can I diffuse while spending time outdoors?
Try the Porch & Patio blend above, with citronella, peppermint, and lavender, on a covered porch or near open doors and windows. Citronella paired with bright, herbaceous oils makes a classic warm-weather diffuser combination.
How many drops of essential oil go in a diffuser?
For a standard 200ml ultrasonic diffuser, 8 to 12 drops total works well. Scale up or down to match your diffuser size and your scent preference.
