Before taking any action, be certain that you identify the insect or fungal disease and use the Integrated Pest Management (IPM) approach to a pest free garden. If your roses do not have to be perfect, then you can tolerate a certain amount of insects. If you want exhibition quality roses, then you may have to rely on more chemical control.
Fungal diseases do not go away when no action is taken. Once a leaflet shows disease, it will not go back to the way it was before infection. You can begin by cutting off (not tearing) the infected parts of the bush. If you wait too long, the plant will naturally shed the leaves (defoliate) but in the interim, the fungi spores continue to multiply and blow around your yard.
Below is an example of blackspot
Below is an example of Powdery Mildew
Below are examples of the early infection of Botrytis, also called gray mold
What is your tolerance for insect damage and fungal disease on roses?
It is a personal question and the answer can change depending on the uncontrollable factor of weather or the amount of time you have to devote to roses or your personal philosophy of what is the right way for you to garden.
I prefer to not use insecticides in my garden because I have fruit trees and mason bees that I nurture for pollination of my fruit. When aphids come to visit my roses, I often see ladybugs working on them, but I often get my hose with a medium spray nozzle and blast aphids with water for a few days in a row. The aphids fall to the ground and since they cannot fly, most do not return. If they are not removed, aphids continue to reproduce and damage roses.
If we have a hot dry June and July and I suspect spider mites will be active. Again, get the hose out with a spray nozzle. Spraying water and a slight rubbing of the leaves, especially on the undersides will deter the spider mites. So the word “spray” is not a bad word in my garden. I spray water, I spray liquid seaweed, I have been known to spray chelated iron and products approved for organic gardening.
Fungal diseases can do a lot of damage is a relatively short period of time. Once you see the damage, you cannot return the foliage to perfect again. As soon as a fungal disease shows, it is best to trim off (not tear off) the disease and do what you can to stop it from spreading. Some roses are resistant to fungal disease by hybridization. That is why you may see one or two roses badly defoliated (in a public garden for example) while others in the area stay clean.
The photos are examples of the continuum of possibilities for your rose garden. The amount of time you have to spend in the garden may change from year to year. Do not get discouraged if pests and disease appear. Contact a local Consulting Rosarian for help.
This is the first of four posts to supplement the information that will be presented on February 25th at 2:15- 3:45 in the Rainier Room.
Roses will uptake maximum nutrients when the soil pH is between 6.0 and 6.5. This reading changes in different locations of the garden. Other factors that change pH include use of chemical fertilizer and when the pH is tested, before, during or after the rainy season. West of the Cascades, the native soil tends to be acidic. (East of the Cascades the soil is alkaline) My Kitsap garden beds have had readings on October 2, 2016 between ph 4.5, pH 5.0 and pH 6.2. I applied granulated lime according to directions on the bag after these readings. You may have heard that lime is a slow acting soil amendment. I waited three months, until late December, to find pH in all rose beds to be pH 6.3 and pH 6.6.
I did not think this chart would project very well in the Rainier Room and even if it were projected, it seems to me to be something to study to fully understand.
The excitement is building now that the holidays are behind us. The 2017 Northwest Flower and Garden Show will be here before we realize it. This is the traditional kick off to spring in Seattle. Speakers and vendors crowd the convention center for a jam packed five days of garden glory. I love the display gardens to get inspired for the growing season. This year I will be speaking about roses on Saturday to kick off the the bare root rose growing season. I am so excited I can hardly wait. My program is finished and gets tweeked every week.
Let me start this discussion by pointing out that some roses are protected by plant patents. David Austin roses and many Weeks modern varieties fall in this category. It is illegal to propagate roses with plant patents. The large rose producers need to protect their investments in roses with plant patents. That said, many old garden roses, polyanthas and miniature roses do not have plant patents. Do your research before propagating roses.
I am not into budding onto rootstock, but I have had modest success with starting hardwood cuttings in fall. I credit my success to the continual rain in the Pacific Northwest providing the outdoor moisture. My method is simple: hardwood cuttings, rooting hormone powder and small potting mix filled containers. Roots form within two months but the starts will not be potted up until next summer or fall.
Hardwood cuttings 10/9/16 (left) and hardwood cuttings fall 2015. (Right)
Saturday I was with a group of 18 very good rosarians from the Tacoma Rose Society. A long time member, George Hedger, passed away and formally left his 450 roses to TRS. Decisions were made to have a rose rescue and dig out, wash and pot the best roses for a sale next spring to benefit our beloved Point Defiance Rose Garden, that George so loved. My guess is the crew processed 170 roses.
I love growing roses but there is one thing I love to do more and that is to talk about growing roses in the Pacific Northwest! If you will be anywhere near Seattle on Saturday February 25, 2017, plan to visit the Northwest Flower and Garden Show. This show is the second largest in the USA. At 2:45 in the Rainer Room, I will have a 30 minute segment of a 90 minute talk on roses. The title of my segment will be Growing Roses Sustainably in Western Washington.
This little rose is a polyantha, ‘Marie Pavier’ that is very healthy and fragrant.
With the dog days of summer upon us, the majority of my gardening chores are done in the early morning or in the late evening. More and more, I am finding myself sitting on the porch under a box fan with a cool beverage and reading a good book.
An early adopter in many respects, I must confess that I have never been able to convert my reading habits from a book to a nook or other electronic reading device. There is just something about the feel of a book, the smell of a book, the satisfaction you get when you complete a book and can snap it shut, after being filled with its knowledge.
I am a firm believer that everyone should have a personal library of the books that they love. Electronics often fail, things get lost in the “cloud”, but I can always go to the shelf and…
On the whole, I average 25-75 emails per week from folks asking rose related questions. About 25% of those are questions related to how to grow roses from seed. Growing roses from seeds can be done. It takes patience. In order to produce a mature rose shrub from a seed is a multi year process and is not for the faint of heart.
the ‘Osiria Rose’ – is actually a rose but is not sold in the U.S.
Many times people who write to me have already purchased seeds. Sometimes, they send along an exotic photo of an unusually colored rose supposedly grown in some far off land. They always tell me that they spent $$$ (+ Shipping & Handling) and are very disappointed with the results. Either the seeds failed to germinate or they produced a totally different bloom than what was advertised. Or, the shrub is spindly, sickly and rarely produces any blooms at…
This gardening season I have been thinking about my rose growing hobby a lot. I like rose horticulture exhibiting, making arrangements and growing the miniature and miniflora roses and I am moderately successful, especially since the move from the short growing season in Minnesota to western Washington. To do really well, a person needs some type of florist frig or other not frost-free frig that will stay at 36* F to hold roses for a week or so before a show. It will keep a perfect bloom in that state for days until needed. All the really good rose exhibitors have a special frig. I do not have such a frig. The frig really only needs to be using electricity for a month or so in June then a month in Sept. to cover all the rose shows in the Pacific Northwest. So I have been wondering, do I want to get such a frig? Do I want to continue showing roses at this level? How many more years would I really want to be showing roses? Would it be worth the effort? What do I really get out of all this? Heaven knows I don’t need more trophies and stuff. I like the recognition and thrill of getting on the head table. I only need one up there for it to be a success. I like being with rose people and judging. Judging is where the real action is, IMHO. So I am conflicted. I like my humble shrub roses with their full fluffy variety of colors. They are not show roses for the most part. Dr. Buck and David Austin are well represented in my rose collection. I am also trying a few of the Kordes varieties this year because of their reputation for disease resistance. So where does this bring me? I will probably continue life without a frig, but I would take one if it magically appeared.
Top row L to R:Honey Perfume, April Moon, Joy a miniature show rose on its second flush, Lena, a cute shrub born in Minnesota.
Bottom: Serendipity and Aunt Honey by Griffin Buck.