Planting a garden filled with thriving, fragrant roses is a dream for many gardeners. But what happens when disappointingly poor growth, shrivelling roots or even plant death occurs after replanting roses in the same soil? This could be the result of rose replant disease, a commonly misunderstood issue that affects not only roses but a variety of other plants as well.
Luckily, by understanding the causes of rose replant disease and following some practical steps, you can prevent this problem and create a flourishing garden.
What Is Rose Replant Disease?
Rose replant disease occurs when roses are planted in soil where other roses (or susceptible plants) were grown previously. The soil becomes a breeding ground for pests, pathogens and harmful microorganisms, significantly impacting the new plant’s ability to establish and thrive.
Although the disorder is most commonly associated with roses, other plants such as apples, cherries and plums are also frequently affected. Symptoms can vary in severity, and in some cases, the issue may not manifest at all. However, understanding its signs and methods for prevention is critical if you want garden success.
Symptoms of Rose Replant Disease
Plants affected by replant disease may show one or more of the following symptoms:
- Struggling to establish: New plantings may fail to settle into the soil and grow poorly, particularly when compared to plants growing in unaffected soil.
- Stunted growth: Expect slow or limited growth after planting.
- Root problems: Roots may appear unhealthy with poor development, often showing signs of rotting and decay.
- Plant death: Severe cases may lead to the complete failure of the plant.
Plants Frequently and Occasionally Affected
Knowing which plants are most susceptible to replant disease can help you take preventative measures.
Frequently affected plants:
- Roses (especially on Rosa canina rootstocks)
- Apple
- Cherry (edible varieties)
- Peach
- Pear
- Plum (on St Julien A rootstock)
- Mountain ash
- Quince
Occasionally or slightly affected plants:
- Raspberry
- Strawberry
- Vine
- Pine
- Spruce
Diagnosing Rose Replant Disease
If you suspect replant disease in your garden, compare the growth of plants in affected soil with those planted in sterilised or unaffected soil. For roses, doing this with a comparison in pots over one planting season is often sufficient.
If the symptoms confirm replant disease, lift the plant, carefully remove the soil surrounding its roots, and replant it in fresh soil where the same species has not previously grown.
Five Steps to Prevent Rose Replant Disease
The good news is that with the right precautions, you can significantly reduce the risk of replant disease and enjoy healthy plants in your garden. Follow these five steps to avoid replanting issues in your roses and other affected species.
Step 1. Replace the soil
Swap the old soil around the planting hole with fresh soil from another area of the garden. Ensure that the planting hole is slightly larger than the spread of the rose’s roots, typically around 60cm (2ft) in diameter and 30cm (1ft) deep.
Step 2. Use cardboard lining
For an extra layer of protection, line the planting hole with a cardboard box with the bottom removed. This degrades over time and encourages the plant to establish itself in the soil without immediate interference from pests and pathogens.
Step 3. Apply nitrogen-rich fertiliser
Boost the plant’s growth with high-nitrogen fertilisers such as sulphate of ammonia or hoof and horn. These nutrients help combat replant disease and support vigorous plant growth.
Step 4. Use mycorrhizal products
Mycorrhizal products, available in sachets, contain beneficial fungi designed to assist root development and improve soil health. Sprinkle these products into the planting hole to counteract the effects of replant disease.
Step 5. Incorporate organic matter
Enrich the backfill soil with well-rotted manure or organic matter before firmly placing it around the roots. This not only improves the soil structure but also provides essential nutrients to the plant. Finish by watering thoroughly to help the plant settle.
The Role of Rootstocks in Resistance
Some rootstocks exhibit higher resistance to replant disease than others. If you’re sourcing new roses or other susceptible species, it’s worth enquiring about resistant rootstocks. For roses, rootstocks like Rosa ‘Laxa’ tend to be more resistant than the common Rosa canina rootstocks.
Other resistant rootstocks include:
- Apples on M27
- Cherries on ‘Colt’
- Plums on Myrobalan B
By choosing the right rootstock, you can greatly reduce the chances of encountering replant disease in future plantings.
Why Pay Attention to Replant Disease
Replant disease may be poorly understood, but its impact on your garden can’t be underestimated. The extra effort required to address soil health upfront will not only save time and money in the long term but also set the stage for a thriving garden filled with vigorous plants.
Keep Your Roses Healthy and Blooming
Rose gardening is a rewarding and peaceful hobby, but dealing with replant disease can make things tricky. By swapping out soil, using nitrogen-rich fertilisers and implementing organic growth boosters, you can avoid this common complication entirely.
Need further guidance for your garden? Stay one step ahead with expert advice and gardening tips. With these preventative measures in place, you’ll soon have a thriving garden to enjoy for years to come.
Further Reading: The History and Importance of the Rose, Growing Beautiful Roses
