Growing Roses on Fortuniana Rootstock
By James Mills
In my twenty years of growing Fortuniana rootstock roses, I’ve learned a lot of things by trial and error as well as much from other rosarians. One of the greatest rosarians I have ever known, Sam Renfroe of Mobile, AL got me interested in growing Fortuniana roses. Wasn’t long before my wife, Daisy, and I became really interested in roses and joined the Mobile Rose Society. I now have over 1000 rose bushes in our garden; most of them are on Fortuniana rootstock.
Roses require at least six hours of sunlight. Since the soil must be well drained, I recommend raised beds or making holes where the roots can go in all directions at least two to three feet. If you can’t have a raised bed, the holes should be at least two feet deep and use the same soil mix as you would in raised beds. I believe that the basic soil mix should be ¼ sand, ¼ loamy soil, ¼ organics, such as horse manure or cow manure and ¼ crushed pine bark. Do not use pine shavings, as it will burn the roots. You also can add other amendments.
You should then have the soil analyzed by sending a sample to your state Agriculture Dept. Your county agent can advise you how to do this. It is very simple. It is important that you keep the ph around 6.0. If the ph is too low, add dolomite lime: If the ph is too high, add sulfur. The more organics you can add to your rose bed, the better the roses will grow. I have found that if your rose bed can generate earthworms, you will have much better roses. The earthworms aerate the soil, and this lets the roots breathe. When you are selecting a site for your rose bed, dig a hole the depth you plan to plant your roses and fill it with water. If the hole takes over an hour to drain, you should amend your soil, or make raised beds.
There are many types of roses as well as many thousands of varieties. Old garden roses, varieties that existed before 1867, are very common here in the south. Rose hybrids developed after this date are considered modern roses. This article is directed primarily at modern roses. Modern roses types include hybrid teas, floribundas, polyanthas, grandiflora, miniatures, mini-floras, and many climbers. Most modern roses are grafted or budded because they do not produce a vigorous root system. The rootstock used is usually from a hardy type of rose such as R. multiflora, Dr. Huey, R. manetti, Fortuniana, or some proprietary to the florist industry.
I have learned through trial and error that no other rootstock compares with Fortuniana for the south. It is resistant to nematodes, which are prevalent here in the south. Nematodes attack the root system of roses and will destroy it. Fortuniana is also resistant to other root diseases. The Fortuniana root system is much larger than those of other rootstocks; its roots are fibrous and extend out from the plant much farther than other rootstocks.
Occasionally, I have found that the rootstock will form a tap root which I would compare to a tap root on a pine tree - I have pulled up tap roots from my older bushes that were up to four feet long. This massive root system is what makes Fortuniana the choice for serious rose growers. The blooms will be larger and the plants will produce more leaves, which in turn, will make the plant grow larger. I have Fortuniana rootstock roses in our garden that are over 12 years old, and continue to get larger each year. I have also found that after the first year, the rootstock is as winter hardy as most other root systems.
Planting your Fortuniana Rootstock Roses
Fortuniana rootstock roses are container grown so you plant them differently than you would plant bare root roses. The roses should be planted the same depth as they are in the container. You should keep the graft union from touching the soil. When the graft union comes into contact with the soil it can began to go back to its own roots. Most roses that are planted with the graft or bud union in the soil revert back to their own roots. (If it goes back to its own roots, it will attract nematodes.)
Returning to planting, you should remove the bush from the container and place it in the hole that you made for the bush. I suggest placing a handful of Osmocote (time release fertilizer) in the bottom of the hole and mix it into the soil. This will give the root system some nourishment sooner than food leaching from the surface. Fill the hole ½ full of soil, and then fill the remainder with water. As the water drains you will see bubbles. These are from air pockets in the soil that the water removes. Air pockets can cause disease to form in the soil. When the water drains, finish filling the hole with soil, then water again. You should immediately stake the rose bush. I recommend using ½” rebar cut in 4’ lengths; tie the bush above the graft as a strong wind can break the graft union.
As the bush gets larger, the stake will support the shallow root system and keep the bush from working loose in the soil. You should use something like old panty hose for ties. If you use wire or string, take an old garden hose and place over the wire or string to prevent bruising the trunk of the plant. After the plant is staked properly, put a handful of Osmocote or other time-release fertilizer around the plant. I’ve also found that a handful of Milorganite is one of the best fertilizers. It is a slow release feeder and has a good source of iron in it. Then I mulch around the bush with pine straw or some other mulch that will deteriorate. This will build up the soil and make the earthworms more plentiful.
Watering your Rose Bushes
Water is to a rose bush as milk is to a baby - it cannot survive without water. Water is even more important than food for the rose bush. In a well-drained bed it can take up to 3” of water/week for the plant to really flourish. I have found the best way to tell if your bushes need watering is to stick your finger in the soil near the bush: If the soil is moist no need to water; if the soil is water logged cut back on the water; if the soil is dry, you’re not using enough water. There are various ways of watering your bushes. I suggest before you even think about planting your rose bushes, you should install some type of watering system. Relying on pulling out the garden hose in the hot days of summer will surely result in your roses not getting enough water. It is too easy to wait until tomorrow to water. Always water your roses in the morning, as this will give them all day to dry out. It will not hurt the leaves to wet them if you water in the morning. In our rose garden, we water overhead and we always water in the morning. In the heat of the summer, the roses seem to respond well to watering overhead.
Feeding Your Rose Bushes
There are many ways to feed your roses and most rosarians have their own secret formula for great roses. I have found that roses really can absorb a lot of feeding, if you water sufficiently. The more water you use the more you can feed your bushes. If you do not water sufficiently, the fertilizer will build up salts and interfere with the root system’s ability to pick up nutrients. In the early spring, after pruning and when the danger of a hard freeze is over, I give each rose bush a cup of Milorganite and a cup of a good time release fertilizer such as Nurseryman Special or Osmocote. Also once a month, I give each rose bush a tablespoon of soluble food such as Peter’s 20-20-20 or Miracle Grow to a gallon of water. Also once a month I give each rose bush a tablespoon of Epsom salts to a gallon of water. This will make new basals break from around the graft. These are next year’s canes, which will make your bushes larger. Probably around the middle summer I would repeat the time-release fertilizer and Milorganite and continue my monthly feeding of soluble fertilizer until around mid-September.
After September I would not feed any more so the bushes could began to harden off for winter. I also recommend remulching your beds with organics such as horse manure, cow manure or mushroom compost, as this breaks down it gives the roses many nutrients and will not burn the roots.
Spraying your Rose Bushes
This is the one thing that keeps most folks from growing roses. Spraying is essential if you want to have great roses. There are some things you must invest in to have good roses. You should have a good sprayer. There are many types of economical sprayers on the market. If you have just a few roses you can purchase a backpack sprayer that will give you sufficient coverage. For just a few more dollars you can purchase a battery-operated sprayer that I think is really necessary to have good disease-free roses. Most discount stores have 5 to 12 gal. sprayers that can be connected to your battery on your lawn mower. You must have sufficient pressure for the spray to be effective. In the south where we live, we are in a constant battle with Blackspot, which will defoliate your rose bushes and eventually weaken them until they die.
Many people are buying disease-resistant shrubs that need little if any spraying, but these roses will never give you the long-stem cut flowers that most people really want. I have found that after you prune your bushes in late winter, if you will spray your roses every 10-14 days with the systemic fungicide Bannermaxx combined with the contact fungicide Dithane or Manzate, you will not have Blackspot. You can spray both of these fungicides at the same time. Every couple of times you spray, omit the Banner Maxx and only use Dithane or Manzate.
I would also recommend you buy an alternate systemic fungicide and once every month or two use the alternate with the Dithane or Manzate. You should also use a spreader sticker with your spray - if nothing else, use a couple drops of dishwater detergent in your spray tank. There are also neutralizers that you can use to make the water neutral such as Indicate 5. Never spray your roses in the heat of the day as you can burn the leaves.
The other things you will have to spray for will be thrips and spider mites. I would use Conserve for thrips. Thrips are tiny insects that get into the buds as they are beginning to open and the buds will not open or if they do, they will be brown and will not be useable. I only spray the buds because the insecticide will also kill other insects on the bush that are very beneficial. These beneficial insects eat spider mites, which will infest your bushes in the heat of the summer.
Spider mites are tiny mites that began on the underside of the bottom leaves and turn the leaves a copper color and will defoliate the bush if not eliminated. There are a couple ways of getting rid of mites. One is to use a water wand and wash the underside of the leaves with a strong force of water or you can use a miticide such as Floramite, Sanmite, or Tetrasan. You can mix the miticide with your regular fungicide spray. I spray my roses once a month with a miticide and don’t seem to have a problem with mites.
The only other major disease your roses might occasionally have is Downey Mildew. This can occur in the springtime when the days are cool and damp. Downey Mildew looks very similar to Blackspot in the early stages but it begins on new growth whereas Blackspot begins on older leaves. The canes will also begin to have purple splotches on them and if this is not corrected it will devastate your garden. I recommend a copperbased spray once every fall and once in the spring. Some of the recommended fungicides are Aliette, Stature, or Kocide. These are very good preventives.
I know this seems like a lot of work to have roses, but the benefits of beautiful cut flowers for your use and for your friends is well worth the effort.
Pruning Fortuniana Rose Bushes
I don’t prune our Fortuniana rootstock roses as severely as we do our other bushes. I’ve found that if you prune Fortuniana too severely, they will have a hard time recovering. The reason is that the massive root system must have lots of energy when the new growth begins. I prune ours around hip high. Most people take all of the old leaves from there bushes as they prune the bush. I don’t and it doesn’t seem to bother the bush. In Zone 8, we prune our bushes middle to late February. If you prune your bushes too early, a freeze can kill or severely damage the bush. So it is better to prune a little later. When cutting your roses, always cut back to a 5 leaflet, not a 3 leaflet and always cut ¼” above the bud eye. If you will cut at the 5 leaflets that are growing to the outside of the bush, it will make the stems grow up and outward. The idea is to make your rose bush look like an upside down umbrella.
It takes any where from 50 to 60 days for a bush to repeat bloom so if you are planning for a special occasion you can figure when to prune the plants. When the blooms are spent you should at least pinch out the old bloom and this will start new growth.
Enjoying your Rose Bushes
Never let growing roses become a job, it should always be a hobby, even though there is work involved. Most hobbies require work. This is why you should have well-prepared beds, have a water system installed and keep your rose beds mulched so pulling weeds will not be a major problem. Just remember that water, good soil and fertilizer means that weeds and grass will try to emerge. You can use a pre-emergent in the early spring, as this will keep the weeds and grass from ever getting a good start. I never use a post-emergent around my roses because any thing that will kill weeds will also kill or damage the bush.
Most people want to begin with the older rose varieties that they have heard about for many years, but there are lots of newer varieties that are more disease resistant and are easier to grow. On the other hand, don’t be deceived by the rose companies that are always trying to convince you to buy varieties that have not been grown in your area. This is one of the reasons we have such a large garden. Daisy and I try to grow new varieties before we recommend them to others. I believe with all my heart there is no other hobby that can give you the joy and pleasure as growing beautiful roses.