Rose Replant Disease

Why does Rose Replant disease occur?

Rose replant disease (sometimes called rose sickness) occurs when a new rose is bought to replace an old one and is planted in the same soil. It is generally considered that the cause is a combination of soil imbalance caused by the removal of trace elements from the soil by the old rose and a natural build-up within the soil of fungal root diseases and soil micro-pests, although rose replant disease is not perfectly understood. When talking to customers on the phone I always draw a parallel with what would happen to a newborn baby deprived of all vitamins and exposed to a range of airborne diseases. If it did not die, it would probably be unwell....

Rose replant is always quite obvious, however, as the new rose looks increasingly poorly. It generally dies or else takes years to recover. When removed from the ground the roots will not have put on much growth and most of the finer roots will have rotted away.

Is there a cure for Rose replant disease?

There is no topical cure for rose sickness. So not really. The problem is below ground. By the time the condition has been recognized it will be too late and there is little point in moving the rose as it will already be sickly and so will struggle to establish. So the trick is to recognise when there is a risk and plant accordingly.

Avoiding Rose replant disease

The following procedure should be followed whenever a rose is planted where another rose was previously grown. By the way - the best advice is - don't put one rose in the hole left by another for at least five years if you can help it. On the other hand, if you can't help it....

Ensure the planting hole is considerably wider and deeper than the spread of the roots – allowing 1” below the graft. In other words, if you put the rose in the hole, the roots do not touch the sides and the graft is at least an inch below the surrounding soil level. This is not how your rose will be planted, it is simply a measure of the size of the hole needed.
Always use soil from another part of the garden or a bag of John Innes No 3 as this is sterilized and weed free. Never, never reuse the soil from the hole when replanting this or any other rose or any member of the rose family e.g. pyracantha, hawthorn, apples etc. It is best put on the compost heap where it will be rebalanced by the time you come to use it again in 12 months.
Before backfilling around the rose use a scoopful of Root Grow and ensure that it is in full contact with the roots. It helps to water the bare roots first and then sprinkle Rootgrow onto them immediately after. Mycorrhizal fungi attach themselves to the plant roots and spread out forming a secondary root system and living symbiotically with the rose, improving the uptake of soil nutrients.
Backfill and then mulch with compost or well-rotted manure.
Water well straight away and then during the first spring and summer. Mulch with well-rotted compost every spring.

Rose Sickness taking hold of an area. Image courtesy of rhs.org

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By Julian de Bosdari