One of the most common questions gardeners ask is how to identify whether a vigorous new shoot on their rose bush is a healthy new cane or an unwanted sucker. Understanding the distinction is crucial for maintaining the health and vitality of your rose plants. In this article, we’ll break down how to differentiate between the two, based on the insights shared by rose expert and garden designer Paul Zimmerman.
Understanding the Basics of Rose Production
Before diving into identification, it’s important to understand how roses are produced. Roses are generally cultivated in one of two ways: they are either grafted or grown on their own roots.
- Own-root roses are propagated directly from cuttings of the desired rose variety. These roses are genetically identical throughout the plant, meaning every shoot that emerges is true to the variety.
- Grafted roses involve attaching the desired rose variety to the root system of a different, often more vigorous, rootstock. This method is widely used around the world, especially in large-scale production.
In the United States, own-root roses are often found in boutique nurseries, while the majority of roses sold commercially are grafted. For those with own-root roses, the good news is that suckers are not an issue. Any new growth is part of the rose you intended to grow. However, if you have a grafted rose, the possibility of suckers is something to watch out for. Follow along in the original video here:
What Is a Sucker?
A sucker is a shoot that emerges from the rootstock of a grafted rose rather than from the grafted variety you paid for. These suckers can be problematic because they are more vigorous and can overtake the desired rose, diminishing its health and performance.
Suckers not only compete for nutrients but also introduce a significant aesthetic issue. Even if the sucker blooms, it won’t produce the flowers of the rose you selected. Rootstock flowers are often simpler, single-petaled, and may only bloom once, similar to species roses. This can create an imbalance in the garden, reducing the visual appeal of your rose and limiting the expected flowering cycle. Over time, if suckers dominate, the grafted rose may weaken or disappear entirely.
Key to Identification: The Bud Union
The simplest and most reliable way to tell the difference between a sucker and a new cane is by examining the bud union. The bud union is the swollen area near the base of the rose bush where the grafting process took place. This is the point where the desired rose was grafted onto the rootstock.
If your rose was planted correctly, the bud union should be slightly buried beneath the soil. However, if you need to check for suckers, gently expose the bud union by clearing away the soil.
How to Identify Suckers
Suckers can sometimes be distinguished by their appearance. Compared to canes from the grafted rose, sucker shoots often have different leaf shapes, are more vigorous, and may produce thinner or more heavily thorned canes. However, the most reliable way to identify a sucker is by its point of origin.
- Locate the Bud Union: Dig down to expose the bud union if necessary.
- Observe the Origin of the Shoot:
- If the shoot emerges from the bud union or above it, it is a healthy new cane from the rose you purchased.
- If the shoot emerges from below the bud union, it is a sucker from the rootstock.
- Identify and Remove Suckers:
- Suckers may grow directly from the soil or from below the bud union. These should be removed by snapping or cutting them off as close to the rootstock as possible.
- Any growth that starts at or above the bud union should be left intact, as it contributes to the desired rose’s health and growth.
Rootstock Variations by Region
Paul Zimmerman highlights that the type of rootstock used varies by region:
- United States: Dr. Huey is commonly used.
- Canada: Multiflora rootstock is prevalent.
- Europe: Laxa rootstock is the standard.
While rootstocks may differ, the method of identifying suckers through the bud union remains universally effective.
Final Thoughts
Maintaining a healthy rose garden means being vigilant about sucker growth, particularly if you have grafted roses. . Suckers tend to emerge during periods of vigorous growth, making post-rainfall or fertilization checks especially useful. By regularly inspecting the bud union and promptly removing suckers, gardeners can ensure that the energy and resources of the plant are directed toward the desired variety.
A good rule of thumb is to check for suckers during routine pruning sessions or at least twice per growing season – once in spring when new growth emerges and again in mid-summer. Suckers are most likely to appear during periods of rapid growth, so additional checks after heavy rain or fertilization can prevent them from gaining a foothold.
As Paul Zimmerman explains, the process is simple and straightforward: anything emerging from the bud union or above is part of the rose you paid for; anything below is a sucker. Keep this in mind, and your roses will thrive beautifully season after season.
Paul Zimmerman is the founder of Paul Zimmerman Roses, dedicated to the philosophy that “Roses Are Plants, Too.” With decades of hands-on experience, Paul specializes in all kinds of roses but particularly antique, shrub, and David Austin roses. A sought-after designer, consultant and educator, he designs sustainable rose gardens for private clients and public institutions both in person and virtually
