Container Planting for Rose Bush Replacements
Howard E. Jones, Consulting Rosarian
Tidewater Rose Society
A few years ago I reached the planned size of my rose garden: where roses have been used to landscape our backyard and the south side of our house, besides having formal beds of Hybrid Teas, Floribundas, and Miniatures. During the 5 or 6 years it took me to make my rose garden a reality, I determined that 300 rose bushes was the maximum number that I wanted to take care of. You see, I am a “neat freak” and it bothers me when the garden is not kept deadheaded and well groomed. I also wanted time left to do other things.
Since completing the size of my garden, I have been planting all of my new roses in biodegradable pots rather than planting directly into an existing rose bed. Actually, I have been planting replacement roses in biodegradable pots for several years. While expanding, new roses were planted directly into the new beds. Roses that were to be planted as replacements in established beds were first potted and then planted in the bed after the rose bush to be discarded was taken out. This was done at any time that the weather and soil conditions were right and that it was convenient for me. No hurry and no pressure.
The year that my garden was completed, I started growing four potted Hybrid Teas at the end of four of my Hybrid Tea beds. They were placed outside of the beds on 18” diameter patio stepping stones that we sunk into the lawn and grown there above ground for an entire growing season. Fifteen-gallon biodegradable pots were used and this size container is large enough to sustain a Hybrid Tea bush indefinitely. The new bushes grew so well above ground that after 2 or 3 years of experimenting, I decided to keep all of my potted replacement bushes above ground for their first growing season. This allows me to evaluate them and gives me some stalling time to decide which roses to take out to make room for my latest acquisitions. I am quite pleased with this system of making replacements. Remember that all new roses that I put in are now replacements.
There are many advantages in this system of container planting and only a few disadvantages, as listed below.
1. Container planting can be done at any time, regardless of weather and soil conditions.
2. Ideal potting soil mixture can be made for maximum root and plant growth.
3. Pots can be moved into a garage or protected area in case of freezing weather after late fall or early spring planting.
4. Roses get off to a quicker start in the spring due to root zone being warmer above ground.
5. Pots can be moved around to experiment with different sun/shade conditions.
6. Roots are protected from competition with roots of older bushes and from site contamination (if there is such a phenomena) until roots of new bush are well developed.
7. Normally will get more growth the first season because of all of the above.
8. Can evaluate the variety and bush for the first season without going to the labor and hard work of planting it in the ground. Is it really a keeper?
9. Rose bush does not need to be removed from biodegradable pot before planting in the ground and the well-established roots are not disturbed.
1. Some extra work in planting in the ground if you decide after evaluation to keep the potted rose bush, although the improved growth should offset this.
2. Will need to water more frequently than bushes that have been planted in the ground. If potting mixture contains one-third to one-half soil that has some clay in it, this will be minimal.
3. Additional cost of biodegradable pot or reusable container (if you take bush out of pot before planting).
4. Need area in the sun to place potted rose bush while evaluating. I have found that my paved parking area is a very convenient location and that my parking area is enhanced by the beauty of the roses.
In making up my potting soil, I use one-third topsoil (soil in which roses have not previously been grown), one-third peat moss or other organic materials (can be any combination), and one-third or other organic materials (can be any combination), and one-third Perlite. I consider the Perlite a very important component as it does not break down and is a permanent soil conditioner. Limestone, gypsum, and a cup of organic fertilizer that I mix myself are added to the potting mixture for each 10- or 15-gallon pot. Also, a shovelful of crushed pine bark would be helpful in this mixture.
My preference of containers is a 15-gallon biodegradable pot that is 75% peat moss and 25% wood fiber. The 15-gallon pot is very heavy when filled with the potting mixture and watered. You may prefer the 10-gallon size, as it is easier to handle and move. Either size gives sufficient space for the roots to develop during the first season, but the 15-gallon pot is large enough for a rose bush to thrive indefinitely. Four-gallon pots are used for Miniatures. Since the bottom of these biodegradable pots will break down after approximately one season above ground due to moisture conditions at the bottom of the pot, you need to repot or plant the bush in the ground after one season. Once the pot has been planted in the ground, it breaks down very quickly due to enzymes and bacteria in the soil and it is difficult to find the remains of the pot after a year or so.
When I plant the potted rose bush, I don’t just bury it in the ground. The hole is dug five or six inches wider than the diameter of the pot and eight or ten inches deeper than the depth of the pot. The top eight or ten inches (the best soil) are placed in a wheelbarrow and the rest into a second wheelbarrow to be discarded or recycled. Peat moss, limestone, gypsum, and Perlite are added to the wheelbarrow that has the eight or ten inches from the top of the hole and thoroughly mixed until it is a homogenous mixture. The bottom of the hole is backfilled with the amended soil so that, when the pot is placed in the prepared hole, the top of the pot is just below the level of the bed. I use an empty pot to make sure the depth is just right before placing the potted rose in the hole. (It is really hard on the back to get a 15-gallon pot back out of the hole once it has been lowered in.)
The soil mix is then filled in around the pot and firmed so that it is still six inches below the bed level. Fill the remainder of the hole with water, let settle, and then fill to the top with the soil mixture and water again. If the pot is placed properly, the soil will be just over the top of the pot and level with the bed. The bud union will be just above or even with the soil level. You can adjust this according to your climate zone and your own planting depth preference. At the time of potting the rose bush, the bud union was placed about one and one-half inches above the soil level and the soil level in the pot was about one inch below the top of the pot. This allows room to hold water and for mulch.
Once the container rose is planted in the garden, it is treated like all other roses in the garden with the exception that water and fertilizer are applied within the area of the diameter of the pot until the pot breaks down--about one year.
As an exhibitor, I find I want to try all of the promising new varieties as they become available on the market, and it is a little frustrating to have to pick and choose since I eventually have to take out a bush for every new bush that I put in. When new beds were being started every year and 50 or 60 new bushes planted each year, this was not a problem. My system of container planting new roses to evaluate a new variety and/or the vigor of the bush before planting in the ground allows me to try more new roses and helps eliminate all the time and work of putting in a new bush that I may be digging up in a year or two. Also, roses that are lost from winter kill or general loss of vigor are replaced with container-grown roses. This system of container planting for replacement roses has worked well for me. You may want to try it and see if it works for you.