We hope everyone has had a great start to the new year. Today we are going to go over some winter maintenance of one of the most beloved plants, hybrid tea roses. Most people don’t know that the rose is actually the national flower of the United States. Patience and discipline will always pay off with hybrid teas.
Some of you know that my father was a personal gardener for several families in Charleston. He was into roses, it was an extension of three things, interaction he had with his father (who grew roses), his belief that flowers were meant to grown and brought into the house (cut flowers and arranging), and the appreciation of living art ( gardens and flowers, he would always say,”Sure that is a beautiful painting, but who grew and built that garden it came from?”).
(Dad, Me, and Clint, Death Valley, Clemson vs Georgia Tech 1991)
Dad was very successful in growing roses for people. As each year went by, more people wanted him to build and maintain a rose garden for them. (We build the gardens mostly in December, and I helped build most of them).
He was so successful, that at one point we had to maintain over 400 bushes in the Charleston area. While January was traditionally one of the leanest months as far as work, February was always the beginning to better living. The garden pictured below had 120 bushes in it.
Growing up this time of year meant two things to me, my birthday is around the corner and we have to work sometimes on the weekends and especially President’s day pruning back and fertilizing roses. The pictures below is a good example of a before and after of such winter work, or should I say “at the pruning and the first bloom of the year.”
The roses located on the two ends of the berm after they have been cut back.
Here is the first bloom of the season with that same berm, left hand side towards the top.
Growing hybrid teas is not an easy task if you are unfamiliar with them or roses in general. It is one of the reasons why “Knock Out” roses are so popular, because they are “carefree,” which the irony in that statement is that one of the breeding parents of “Knock Out” was shrub rose cultivar called, “Care Free Beauty” developed at Iowa State University. Still one of the most important steps to having great blooms year after year is the winter pruning. If you are trying to grow hybrid teas like a shrub full of flowers, you will have a headache, if you approach it like an orchard point of view managing a framework to grow off of, you will have success.
A little over a year ago, I acquired one of my dad’s clients. Looking back, I have spend more time in that garden, than I did all 4 years of high school. When my father’s health started to fade, one of the owners who had been retired decided to take over. My dad tried teaching him everything he needed to know, unfortunately, there became a point where the owners health was questionable. So things were let go and the garden has matured a lot over the years. To much of my surprise, when I started working back in it, the same roses I planted many moons ago were still there. So instead of just start doing things by the calendar as my dad left in notes, I wanted to focus on the nutritional health and observe them through the year to begin a recovery process.
The winter maintenance we are going to talk about is broken down into three parts, pruning, fertilizing, and spraying preventatively for black spot fungus. First, we are going to talk about pruning.
Below you will find the tools you will need for pruning. The first things you will need is clean sharp hand pruners, a hand saw, gloves, and knee pads or a kneeling cushion.
The next tool you might need, it depends if your roses were grafted or budded, is a wire brush. If your roses were grafted, the graft union will grow with time and get bark like. You are going to want to gently and I mine gently scrap this outer bark. What happens is that from time to time new shoots emerge out of the graft union. If your roses were budded, Star Roses out of Texas buds their roses, there is typically no need to do it unless you start seeing a lot of bark build up.
The next thing you will need is some wood glue, preferable fast setting, water resistant, and outdoor applications.
The last major thing you will need to get is a spray bottle and denatured alcohol. You will use this to sanitize the tools before and after pruning each plant.
I dilute the alcohol to approximately an 80% alcohol solution with water. In a quart spray bottle you would fill will 25.6 floz of alcohol and then add 6.4 floz of water.
Depending on what your local ordinances say about garden debris, you might need to have some bags as well. I do not recommend throwing the remnants in a compost pile, unless you are going to make ash and burn the compost. Burning your prune debris and using the ash is fine, but realize what affect that will have on the soil p.h (increases it).
Now once you have all your tools you might want to carry them all in a five gallon bucket as a matter of convenience and efficient production of work, as you move from bush to bush.
As far as pruning back there are some general rule of thumbs but you must also take into consideration individual growth and health of each bush. Pruning back 18 to 24 inches is typically favored. If you observe brown interior of the cane, keep cutting back until you see white. If you prune back due to brown interior of the cane and the cane is less than 12 inches, go ahead and prune out the cane.
When I make my cuts, I do so with a slight angle away from the bud I am trying to promote to grow.
If the canes have buds emerging within the 18 to 24 inch range you want to leave 4 to 6 inches of cane above the bud.
You want to remove weak canes, less than pencil size in width. You want to remove canes that cross back through the center. You also want to observe if you can how many nodes/ buds are on a cane as they are the future growth of the plant, leaving as much as possible but not to leggy, because you may have to stake the bush later. You will also want to cut down any rootstock shoots you may encounter. You also have to take in consideration of surrounding plants competing for light, water, and space.
When bare root roses are sold they are graded on the number of canes they have, quality roses typically have at least four healthy canes on them. You want to have the same amount at a minimum each year during the “prune down.”
What is very important is that after you have made cuts, scraped the graft union with the wire brush, and cleared away debris from around the base, you need to seal those cuts with glue.
Yes, there will be times where you have to make tough decisions and prune out a lot. The old saying,”When in doubt, prune it out,” holds true.
Once you have finished pruning, the next step is to apply some fertilizer. The fertilizer that is going to be applied contains no nitrogen. There are 4 components that get applied. This method was a standard year in and year out for my dad. Typically, we would conduct a soils test in october and evaluate future needs and make adjustments accordingly.
The first component to be applied is Bone Meal. It is excellent source of Phosphorus and becomes moderately available. It is helpful to microorganisms in the soil that can process it and make it more readily available. We apply one cup of Bone meal around the base of the bush.
The next component we apply is Sulfate of Potash Magnesium (Sul Po Mag). You can apply Magnesium sulfate as a substitution. The Sul Po Mag or K-Mag as it commonly referred to was very expensive to acquire growing up, so my father used the Mag Sulfate, the only difference is the additional Potassium that is applied. Potassium has an extremely important role in plant physiological function as it pertains to water regulation. Magnesium also has an important role in how water is split to give off energy at a cellular level. We apply 1/2 cup of Sul Po Mag to the bush around the base.
Third component we apply is Triple Super Phosphate. It is a great source of phosphorus as well, it is used in addition to bone meal to provide another source of P. While most of our soils are high in P, roses can be heavy accumulators of P. Phosphorus is consumed in smaller quantities than Nitrogen, Potassium, Calcium, and Magnesium, yet it is important for ATP Adriene-Triose Phosphate, which is the energy packet that is created in photosynthesis and used in many other functions. Phosphorus availability in the soil can vary for many reasons, high calcium and iron levels can have a negative interaction. We apply 1/4 cup of Treble Phosphate per bush. In the summer we may or may not repeat this application. Next fall we will test the soil and monitor the usage based from results, but for now we make the general application.
The fourth component we apply is a tablespoon of minor elements. Here again, this repeating an old way of doing things without a soil test. Numerous Rosarians, Gardeners, and people developed their own methods and recommendations from “life experience” fortunately there was been numerous works that have real world application parameters to them. While we don’t discourage the usage of minor elements in this application of recovery, we will make judgement calls in the future from soil test results. Minor elements can very tricky to work with, if you go to far once way with one element, you might actually hurt the availability of another.
In the first week of March, we will make an application of 1/4 cup of Rose-tone, Plant-tone, or Bio-tone. In the third week of March we will make our first major application of granular fertilizer at a one cup per bush.
Now that you have pruned them and feed them, it is time to make a preventative application of inorganic salt based fungicide against Black Spot fungus.
Growing up we sprayed and sprayed and sprayed roses over and over and over. We used a three way fungicide and insecticide. The only time it would change was when the chemical company changed it. What I have learned from my education and life experience is that managing disease is the toughest part of any crop management. We have gotten to a point in society were we have developed fungicide resistant versions of these diseases.
Black Spot is the age old enemy of rose growers everywhere. Its’ first cousin is Apple Scab. While I was at Clemson, I had to develop a Integrated Pest Management Program for a class project, I chose black spot for roses. Through my research, I came across management in Apple orchards with Bordeaux mixture. Like the vineyards of France that once were, the repeated use of the Bordeaux mixture lead to copper toxicity in the soil. It essentially kill off the beneficial microorganisms and was at elevated levels that other metal elements where being either locked up or blocked out. While Copper does play an important role in photosynthesis with electron movement after the splitting of water along with Iron, it typically is found at adequate levels in most soils. Even if you want to correct a deficiency of it, it only takes a very small amount over an area.
Still what cannot be ignored is how effective it can be in combating fungus and particularly black spot. My dad never used Bordeaux mixture in the winter. I have meet some other rosarians while working at Cross Seed garden center that swore by it.
As I am looking at the future of this recovery process of these very old roses, I know that controlling the black spot will be important to help them recover, because they need to build up as much carbohydrate reserves while still using a lot of energy to produce blooms. What I have found is that going back to the older chemical application of inorganic metals to be very effective against pathogens we face today. Copper always sticks out. So, I made the decision of instead of using Bordeaux mixture this year. I would use a fixed copper solution this year, check for copper in the soil and adjust the Bordeaux mixture for next year.
The liquid copper solution I am using this year calls for 3 teaspoons per gallon. I made a solution slightly weaker and plan to apply over a 3 week period of once a week. In March, I will switch over an product that is mostly inorganic metal of Manganese and Zinc. It is called Manzate, Dithane, and a host of other names. Again its’ mode of action is similar to the copper solution. I will make 2 applications of Dithane in March, then switch to a relatively newer formulation of inorganic salt being used in Potassium Bicarbonate. If that sounds familiar, Calcium Bicarbonate is Baking Soda. Both the Potassium and Calcium Bicarbonates do increase the surface p.h. on the leaf making the environment less favorable to Black Spot, one half of the Bordeaux mixture does this as well since it is burnt lime. The potassium bicarbonate also provides some potassium which is readily absorbed through the leaf as well. In May, we will use Calcium bicarbonate two weeks in a row, after that,we will use a silicon liquid fertilizer spray to toughen the cuticle and hopefully slow the progression of black spot.
We may try a synthetically constructed fungicide or a combination of fungicides later. We really don’t want to get into the routine of spraying those harsh chemicals, because there becomes a point where the climate makes spraying useless. Our goal is to slow down and delay the start of Black Spot spreading in the Spring and try to stunt it in the fall when the conditions are right to do so.
While we will focus on increasing inputs this year to help with recovery, we must also take into consideration there comes a point where it financial is not worth it to add extra inputs. We will keep a close eye on how these old roses response to our inputs. If they improve and thrive it will be a blessing, but if they don’t it not bad as they have lived a long life, produced many flowers, and have served their purpose during their existence. There is a saying in horticulture, once a A grade plant becomes a B grade, it can never again become an A grade. As much as people want to think otherwise, that is the truth.
In closing, we hope this blog has helped you with an understanding on how to grow hybrid tea roses. We will post some addition blogs in the future covering the recovery process and other information as it pertains to roses. As always, we want to thank you for taking the time to read our blog and don’t forget to, “Grow Forward.”