Tips for battling black spots on roses

  • By Greg Charles St. Petersburg Times
  • Thursday, July 21, 2011 12:01am
  • Life

Q: We recently transplanted roses given to us by a neighbor. They seem to be doing fairly well and we have wonderful flowers. We did do some pruning but there are black spots on some leaves. Can you help?

A: Black spot on a rose is inevitable, especially on the thousands of grafted hybrid tea

s, grandifloras or floribundas. There are cultural measures you can provide to reduce black spot.

Prevent irrigation from hitting foliage; make sure that your roses are in full sun; and pick diseased leaves off plants as well as off the ground and discard in the trash.

Begin a pesticide/fungicide spraying treatment program on either a weekly or every-other-week basis. Starting with two of the least-toxic classes would be 70 percent neem oil products like Fertilome Triple Action Plus or Monterey 70 Percent Neem Oil.

A good remedy is 1 heaping tablespoon of baking soda (sodium bicarbonate), 1 tablespoon horticultural or neem oil and 1 teaspoon dish soap in 1 gallon of water. A commercial preparation, Bonide Remedy, adds the nutrient potassium, an immune booster.

Sulfur products like Fertilome Dusting Sulfur or Hi-Yield Dusting Wettable Sulfur or copper products like Fertilome Blackspot Powdery Mildew Control or Hi-Yield Copper Fungicide gives you two more classes of treatment.

Other products are more toxic, but you may try Fertilome Liquid Systemic Fungicide, or Ortho Max Garden Disease Control or Spectracide Immunox Multi-Purpose Fungicide. The goal is to rotate two or three classes of products so the disease does not become resistant, such as rotating 70 percent neem oil, and dusting sulfur or copper and a product containing chlorothalonil, such as Ortho Max Garden Disease Control.

All of these products need to be sprayed on a regular basis because they protect the plants before diseases appear. Always read the label for rates, active ingredients and personal protective equipment needed.

For more information on rose-growing (and much more), many publications can be found at edis.ifas.ufl.edu and gardeningsolutions.ifas.ufl.edu.

Talk to us

> Give us your news tips.

> Send us a letter to the editor.

> More Herald contact information.

More in Life

Kim Crane talks about a handful of origami items on display inside her showroom on Monday, Feb. 17, 2025, in Snohomish, Washington. (Olivia Vanni / The Herald)
Crease is the word: Origami fans flock to online paper store

Kim’s Crane in Snohomish has been supplying paper crafters with paper, books and kits since 1995.

The Musical Mountaineers perform at Everett’s McCollum Park on June 14, 2025. (Photo courtesy of Adopt A Stream Foundation)
Photo courtesy of Adopt A Stream Foundation
The Musical Mountaineers perform at Everett’s McCollum Park on June 14.
Coming events in Snohomish County

Send calendar submissions for print and online to features@heraldnet.com. To ensure your… Continue reading

A woman flips through a book at the Good Cheer Thrift Store in Langley. (Olivia Vanni / The Herald)
Pop some tags at Good Cheer Thrift Store in Langley

$20 buys an outfit, a unicycle — or a little Macklemore magic. Sales support the food bank.

Audi SQ8 Wows In Motion Or At Rest. Photo provided by Audi America MediaCenter.
2025 Audi SQ8 Is A Luxury, Hot Rod, SUV

500 Horsepower and 4.0-Second, 0-To-60 MPH Speed

Nedra Vranish, left, and Karen Thordarson, right browse colorful glass flowers at Fuse4U during Sorticulture on Friday, June 7, 2024, in Everett, Washington. (Olivia Vanni / The Herald)
Everett’s Sorticulture festival starts Friday

Festivities will include art classes, garden vendors and live music.

The Mukilteo Boulevard Homer on Monday, May 12, 2025 in Everett, Washington. (Olivia Vanni / The Herald)
‘Homer Hedge’: A Simpsons meme takes root in Everett — D’oh!

Homer has been lurking in the bushes on West Mukilteo Boulevard since 2023. Stop by for a selfie.

Ellis Johnson, 16, left, and brother Garrett Johnson, 13, take a breather after trying to find enough water to skim board on without sinking into the sand during opening day of Jetty Island on Friday, July 5, 2019 in Everett, Wash. (Olivia Vanni / The Herald)
Epic ways to spice up your summer

Your ultimate guide to adventure, fun and reader-approved favorites!

Sarah and Cole Rinehardt, owners of In The Shadow Brewing, on Wednesday, March 12, 2025 in Arlington, Washington. (Olivia Vanni / The Herald)
In The Shadow Brewing: From backyard brews to downtown cheers

Everything seems to have fallen into place at the new taproom location in downtown Arlington

People walk during low tide at Picnic Point Park on Sunday, March 3, 2024 in Edmonds, Washington. (Annie Barker / The Herald)
Beach cleanup planned for Picnic Point in Edmonds

Snohomish Marine Resources Committee and Washington State University Beach Watchers host volunteer event at Picnic Point.

Bar manager Faith Britton pours a beer for a customer at the Madison Avenue Pub in Everett. (Olivia Vanni / The Herald)
Burgers, brews and blues: Madison Avenue Pub has it all

Enjoy half-price burgers on Tuesday, prime rib specials and live music at the Everett mainstay.

Ian Terry / The Herald

Rose Freeman (center) and Anastasia Allison play atop Sauk Mountain near Concrete on Thursday, Oct. 5. The pair play violin and piano together at sunrise across the Cascades under the name, The Musical Mountaineers.

Photo taken on 10052017
Adopt A Stream Foundation hosts summer concert on June 14

The concert is part of the nonprofit’s effort to raise $1.5 million for a new Sustainable Ecosystem Lab.

Edie Carroll trims plants at Baker's Acres Nursery during Sorticulture on Friday, June 6, 2025 in Everett, Washington. (Olivia Vanni / The Herald)
Sorticulture, Everett’s garden festival, is in full swing

The festival will go through Sunday evening and has over 120 local and regional vendors.

Support local journalism

If you value local news, make a gift now to support the trusted journalism you get in The Daily Herald. Donations processed in this system are not tax deductible.