Organic Rose Gardening: Dormant Oil Application for Pest Prevention

Dormant oil application to my roses is the most important pest prevention task for me as an organic rose gardener. The dormant oil is horticultural oil diluted in water. Horticultural oil is available at most nurseries. As a dormant spray, the horticultural oil is less diluted than it is when its used after plants have leafed out.

The importance of the horticultural oil for the organic rose gardener is that it suffocates many pest and their eggs before they become active as the weather warms up. It's good as a control for aphids, spider mites, scale, sawfly, and thrips.

The dormant oil should be applied all over the canes of the roses. The easiest time to do it is after pruning because all the unnecessary wood has been removed; but, if you will not complete your rose pruning until the leaves have already begun to emerge, do it now.

The only brand that I know of is Bonide All Seasons Horticultural & Dormant Spray Oil (see photo below).



For related posts on Rose Pruning, see:

http://heirloomgardener.blogspot.com/2008/02/how-to-prune-roses-part-i-introduction.html

http://heirloomgardener.blogspot.com/2008/03/how-to-prune-roses-part-ii-old-rose.html

Protect Your Roses Now: Spray Dormant Oil Before Your Roses Leaf Out

This weekend, I applied Dormant Oil to all of my roses. This is the best organic pest protection that you can give to your roses, as it smothers over-wintering insects and their eggs. As I wrote in a post last year:

"The dormant oil is horticultural oil diluted in water. Horticultural oil is available at most nurseries. As a dormant spray, the horticultural oil is less diluted than it is when its used after plants have leafed out. The importance of the horticultural oil for the organic rose gardener is that it suffocates many pest and their eggs before they become active as the weather warms up. It's good as a control for aphids, spider mites, scale, sawfly, and thrips. The dormant oil should be applied all over the canes of the roses. The easiest time to do it is after pruning because all the unnecessary wood has been removed; but, if you will not complete your rose pruning until the leaves have already begun to emerge, do it now. The only brand that I know of is Bonide All Seasons Horticultural & Dormant Spray Oil."

Ask Heirloom Gardener: What Should I Do About Black Spot on my Roses?

Question from the mailbag (heirloomgardener [at] aol [dot] com): I have about 30 rose bushes and most are struggling due to black spot. What should I do?

Answer from Heirloom Gardener: Regarding the black spot, I wouldn't worry about it at this time of year. It won't kill the plant, even if all of the leaves fall off. If you want to prevent black spot on your roses next season, start your maintenance in the spring. I spray dormant oil right before the plant leafs out which kills any over-wintering spores that cause black spot as well as insects, etc. If you spray it now, it will kill the plant. After the plant leafs out, I spray with neem oil that smothers the spores every two weeks except during the heat of summer when it will burn the leaves.

Related posts: Dormant Oil Application for Pest Prevention

How to Protect Vegetables from Groundhogs, Rabbits and Squirrels, Part 1: A Chicken Wire Raised Bed Cover

Dear Messrs. Groundhog, Rabbit, and Squirrel,

My friends over at Gardening Gone Wild asked me to write to you to discuss the status of our current dispute. While I have such a harmonious relationship with so much of the other wildlife in the garden--the birds, the toads, the salamanders--I regret that our relationship has become so acrimonious, particularly as it relates to the vegetables.

While I am flattered that you like the vegetables as much as (or perhaps even more than) we do, I find that your appetites leave something to be desired, namely leftovers. Last year, the garlic spray kept you away from many of the vegetables, but I was disappointed to still find teeth marks on my vine-ripened tomatoes and zucchinis, not to mention the fruitless pumpkin and watermelon vines whose flowers you devoured. I can no longer bear your rude interruptions.

In response, I have asked my dear husband to make a simple, custom-fit chicken wire vegetable box cover to keep you away. What it lacks in aesthetic contribution to the garden, I hope it makes up in efficacy. In the future, please find food elsewhere in the wild or, if I may be so bold to suggest, cultivate your own vegetables.

Best wishes,

Heirloom Gardener
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UPDATE: Part 2 of this series discusses adding chicken wire around the post and rail fence. Part 3 of this series discusses reinforcements to chicken wire raised bed cover after a break-in.
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Related posts:

• Advice Wanted: How to Keep Rabbits Out of the Garden
• Keeping the Deer Out of the Backyard: the Deer Fence
• Keeping the Groundhog Out of the Cutting Garden
• Organic Pest and Fungus Control: Garlic Barrier - Yes, It Really Works
• Organic Rose Gardening: Dormant Oil Application for Pest Control
• Organic Pest Control: Colorado Potato, Threelined Potato, and Japanese Beetles

The Best of Heirloom Gardener (updated as of March 2009)

I. Trees, Shrubs, and Plants

• Twelve Great Nurseries for Heirloom Plants: Roses, Perennials, Annuals, Bulbs and Seeds
• Two Perfect Flowering Plants for Arbors: Betty Corning Clematis and Dortmund Rose
• Growing Tulips in New Jersey: Squirrels, Deer, and Clay Soil
• Container Plantings: Variety, Soil, and Care
• Twelve Months of Garden Color in New Jersey (Zone 6b)
• Hardy Annual and Biennial Self Seeders
• Calendar for Forced Branches: When to Cut Various Flowering Branches for Forcing
• Forced Branches and Bulbs: Forsythia, Hyacinth, Tulips, Muscari, and Crocus
• Garden Bloggers' Bloom Day
• Index of Rose Photos

II. Pruning

• How to Prune Caryopteris, Spirea, Butterfly Bush, Pee Gee Hydrangea, Annabelle Hydrangea, Smokebush, Elderberry
• How to Prune Pee Gee Hydrangeas and Wisteria
• Hydrangeas: Why and How to Prune
• How to Prune Roses, Part I: An Introduction
• How to Prune Roses, Part II: Old Rose Pruning Secrets
• How to Prune Roses, Part III: Why Prune?

III. Hardscaping

• Path Makeover: Replacing the Terra Cotta Stepping Stones with Pebbles
• Maintaining the Pebble Path
• Creating Space for a Garden: the Cutting Garden
• Four Year Makeover of the Front Garden: How to Improve Boring Suburban Landscaping

IV. Gardening With Children

• How to Build a Children's Playhouse (the Fort)
• How to Build a Sandbox
• Ten Tips for Planning a Children's Garden
• Five Tips for Growing Edibles with Children
• How to Make a Crown and Boutonniere with Fresh Flowers

V. Vegetables and Herbs

• How to Build Raised Beds (on a Slope/Hill)
• Organically Preparing the Soil for Planting
• Farmer's Almanac Spring Planting Schedule (March/April) and Heirloom Seed Sources
• Farmer's Almanac Spring Planting Schedule (May)
• How to Make the Perfect Soil Mix for Seed Sowing
• Baker Creek Heirloom Seeds - the best heirloom seed offerings
• How to Build a Planting Grid for Square Foot Gardening
• How to Make a Planting Square to Uniformly Space Your Seeds
• How to Plant Corn the Way Squanto Taught the Pilgrims
• How to Plant Potatoes and Harvesting Asparagus

VI. Pest Control

• Advice Wanted: How to Keep Rabbits Out of the Garden
• Keeping the Deer Out of the Backyard: the Deer Fence
• Keeping the Groundhog Out of the Cutting Garden
• Organic Pest and Fungus Control: Garlic Barrier - Yes, It Really Works
• Organic Rose Gardening: Dormant Oil Application for Pest Control
• Organic Pest Control: Colorado Potato, Threelined Potato, and Japanese Beetles