Tuesday, May 15th, 2012...7:32 am

How to Prevent Thrips From Distorting Rose Flowers

Teeming with life by elizabethdonoghue

My roses are in bloom already. It is amazing to see roses in bloom two to four weeks early. But since all the other flowers opened early, why shouldn’t the roses?

One dreams that insects wouldn’t enjoy the roses as much as I do; but unfortunately roses are one of the most beloved flowers for all sorts of nasty insects.  I had been lucky, except for Japanese beetles, I had not had many insect problems on my roses in past years. But all good things must come to an end.

It was such a warm winter where I live with so few hard frosts and so little deep snow, I worried that this year I might see more insect problems than I have had in the past. And this year my roses have proven that I did not worry in vain. I have an extraordinary amount of buds on the rose bushes and the leaves looked so beautiful and healthy: but in the last few days I have never seen so many chewed leaves and damaged flowers as they open. From the looks of the rose flowers, I suspect I have thrips in my roses.

Thrips are nasty insects that do a lot of damage to the flowers, but are not injurious to the plant. Thrips are one of the main insect pests of the rose flower. They are small insects that lay their eggs in the flower and the hatching insects cause the rose flower to be distorted and ugly. See here.


I had read that planting Alliums, plants in the onion family, near roses would help prevent thrips. I have three clumps of Globemaster alliums near my rose bushes. I know to keep the rose bed weed-free and clean in the winter. I did that. But those did not prevent the thrip problem. Now I am going out to heavily water the area around the roots of the roses to see if I can drown any thrip pupae in the ground. And I plan on making worm compost “tea” to spray on my rose shrubs. I have heard that this “tea” helps plants fight diseases and perhaps insect problems. Directions for making this tea is here.  But please don’t think this is tea for humans to drink

Since I do not use harsh pesticides, I ran to the hardware store to buy more Safer Rose insect spray which is organic. Their rose spray says it gets rid of thrips. I sprayed today and plan to spray every few days in the hopes that I can eliminate the problem.  See here.  I hope the thrips don’t get resistant to the spray. I have also read the recipe for a home remedy for thrips which I have never used but am tempted to try because all the ingredients are disliked by insects and seem benign. Maybe between the Safer spray and this recipe, I will have the thrips move on to another place.

Garlic, Peppers & Onion Insecticide

2 hot peppers
1 large onion
1 whole bulb of garlic
1/4 cup water

  • Toss in the food processor and add water, blend until a mash is made. Cover mash with 1 gallon hot (not boiling) water and let stand 24 hours. Strain. Spray on roses, azaleas, vegetables to kill bug infestations. Bury mash in ground where bugs are heaviest. Good for thrips, aphids, grasshoppers, chewing and sucking insects.

If you live on the west coast the thrip population is most commonly the Western Rose Thrip.   Even though this article is from the Marin Rose Organization, everyone should read the article if you have thrips in your roses, because the Marin Rose Organization gives some chemical treatments to get rid of thrips if you are inclined to not go the organic route.

If you watch this vide0, you will see how small thrips are and get more information on eliminating them in your roses.

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