The problem varies in severity and sometimes does not occur at all.
An indication can be obtained by test planting several plants of the same variety in both the soil in question and in other soil which has never grown that plant, and comparing vigour over the first one or two seasons. For roses, a comparison in pots over one season would probably be sufficient.
If the problem occurs, lift the plant, shake off the soil and replant in another site where the species has not been grown before. The plant will often recover.
Five steps to avoiding replant disease:
STEP 1: Swap the soil with fresh soil from another part of the garden. The soil should be removed to make a planting hole that is a few centimetres larger than the full spread of the roots. This is usually about 60cm (2ft) diameter and at least 30cm (1ft) deep.
STEP 2: Some gardeners have used a cardboard box with the bottom removed to line the hole; by the time the cardboard rots away, the plant has established.
STEP 3: Boost plant growth by applying fertiliser high in nitrogen, such as sulphate of ammonia or hoof and horn.
STEP 4: Mycorrhizal products are claimed by the manufacturers to be effective in counteracting replant problems. These usually come in a sachet and can be sprinkled into the planting hole.
STEP 5: Place the plant in the ground. Improve soil structure by incorporating some well-rotted manure or organic matter into the back-fill soil and firm this around the roots. Water well.
Resistance: some rootstocks confer resistance. Roses on Rosa 'Laxa', apples on M27, cherries on 'Colt' and plums on Myrobalan B show more resistance than those on other commonly used rootstocks. Roses on Rosa canina and flowering cherries on Prunus avium are more susceptible.
No chemical soil sterilants are available to home gardeners. Soil sterilisation by steam is possible, but difficult and expensive to organise.