Do Plants Repel Mosquitos? by Donna Duffy

Photo courtesy cdc.gov

 Ask any gardener – they will tell you that it’s a buggy year. The mosquitos seem especially ferocious this summer, which made me wonder if there are any plants that will repel mosquitos. Here’s what I learned from CSU’s research.

Photo courtesy everydayhealth.com

Rumors and misinformation abound regarding plants that will repel mosquitoes in home landscapes. Common plants purported to repel mosquitoes include catnip, peppermint, rosemary, marigolds, Eucalyptus and Artemisia species, to name a few. None of them will repel mosquitoes by merely growing in a landscape. The volatile oils purported to have repellent properties are released when plants are crushed or burned. No data exists to support their effectiveness as repellents. Check out Plantalk’s publication Do Plants Repel Mosquitos for more information. 

Since we can’t depend on landscape plantings to repel mosquitos, the next best thing is to try to repel them by other means. To keep mosquitoes away during outdoor gatherings, burn Citronella candles. Lemon grass, Cymbopogan nardus, a course grass-like plant, contains Citronella oils. Burning candles with wicks saturated with the herb, myrrh is also quite effective at keeping many insects away. In fact, ancient Egyptians used myrrh as a fumigant.

If insects such as mosquitoes have already become a problem, many herbs can be used directly on the skin as repellents. Infusions of 50% Chamomile and 50% Elder leaves dubbed on skin are effective for up to 20 minutes. Infusions are much like making tea, boiling water is poured over the herb and the herb/water mixture is then left to steep for 10 to 15 minutes. The remaining liquid is strained and used as the repellant.

As well as infusion, other properties of herbs such as their essential oils can be used as repellents. Essential oils such as Lavender, Tea tree oil and Citronella from the stone root, Collinsonia canadensis can be worn on the skin and in hair to effectively keep mosquitoes away. It is best to dilute these powerful essential oils in a little olive oil and test this new mixture on a patch of skin before applying to ones entire body. More information can be found in CSU’s publication Plants Help Keep Mosquitos Away.

Don’t let the mosquitos chase you indoors – grab a repellant and make your stand!

Deadhead Flowers for More Blooms by Carol King

July can be an exciting month in the garden. The results of all the hard labor in the spring are beginning to be evident: lots of blooms, especially monarda, black eyed susan, shasta daisy, day lilies, lavender, Russian sage and yarrow; the annuals are looking great and the grass is still green enough!

I spent Sunday deadheading, pinching, cutting back, and disbudding. I know this sounds like torture techniques performed on some poor wretch in a medieval novel, but these actions are just what most blooming flowers need. These methods will increase and provide continuous blooms throughout the season. They also help to keep the garden tidy; flowers compact and help you get that special blossom you want to win the prize in the county fair!

Jeffco Horticulture Staff Member Utley Takes on New Challenges by Jacki Paone

Horticulture Agent , Curtis Utley with Master Gardener Clinician, Allison Millich, present at the Joint Meeting of the Board of County Commissioners and CSU Extension Advisory Committee in June. County Manager, Ralph Schell, in the background.

Curtis Utley, a member of the CSU Extension Horticulture staff in Jefferson County since 2003, has been promoted to Extension Horticulture Agent.  With the promotion come additional challenges in Extension reporting, supervision, writing and program delivery.

Psyllids Are Coming! Plant lice on Tomatoes by Patti O'Neal

Adult Psyllids photo Michigan State University Extension

Reports of sightings of this insect pest in Northern Colorado has set the alert for us on the Front Range.  The potato/tomato psyllid  is a member of the family known as “jumping plant lice” and is very damaging to tomatoes in particular.  It is time to start monitoring your tomatoes on a regular basis for evidence of this pest in your garden. 

Psyllids do not overwinter here in the cold climate of Colorado.  They blow up from Mexico, Texas and Arizona.  Some years are worse than others. And because they are found in one place does not mean they are in another.  Monitoring is the key.  When they are here, they can do a great deal of damage to tomato and potato crops. The home gardener is not exempt and should be on alert to catch this pest before it gets out of hand. 

Happy Fourth! Nature's Fireworks!