There are many reasons why roses will either fail to break dormancy after winter or may begin deteriorating during the growing season. Below are the most common reasons that are presented to us by our customers.
Please keep in mind that when you plant a bare root rose it will not normally start to grow immediately, it will wait for the correct conditions before it will break dormancy. This may be after your established roses have started to leaf.
As a general rule - If it is green, it will grow (with the correct conditions).
The first and most common reason is dehydration:
Water is the Key to Life!
Watering correctly is the most important factor in growing healthy roses.
Roses have a reputation of being drought tolerant, and this is true once they are established. However, when planting new roses, it is important they are kept moist through regular watering. New roses that do not receive adequate water will delay breaking dormancy, suffer dieback, or simply wilt and die.
For more information on watering roses, click here.
Fertilizing at the time of planting can cause plant failure and/or die back in newly planted roses.
If the fertilizer is too strong or applied to high quantities, roses will also experience symptoms of die back, wilting or burnt foliage and sometimes plant death.
Also known as glyphosate-mono (isopropylammonium)
In the past that some gardeners have been known to prepare new beds by spraying a herbicide or weed killer on the ground before building up the soil. In this situation, glyphosate - the main ingredient contained in such chemicals - will stay in the soil for extended periods of time, causing damage to any roses being planted there.
Spraying the garden edge or spray drift from another part of the garden can also effect roses.
Beware of purchasing soil which has been kept weed free by spray.
Roses have a bad response to Glyphosate and will either not break dormancy or will grow, but with multiple spiky leaves coming from the leaf buds. Please click here for more information on Glyphosate damage in roses.
Planting a rose where one has been before:
Roses do not like being crowded. In nature they prevent this by releasing a chemical into the soil to claim their spot, inhibiting any other roses from growing to close to their roots. This chemical will last in the soil for a year, after the plant has died or is removed, before wearing out.
If you wish to plant a rose back in the same spot as a rose was previously planted, then you will have to change the soil.
A rose will stay dormant or grow very poorly if this is NOT done.
Roses need a pH of around 6.5 which is slightly on the acidic side of neutral. If the pH is too high then a growing rose will develop yellow in the leaves. If too acidic it may not grow at all.
Please use a pH test kit from your local garden centre to test the soil. If the results indicate poor soil levels, go to your local garden expert for advice on how to change the pH in your area.
Click here for more information on pH in the soil.
The weather is too cold:
Roses like to be warm and go to sleep if chilled. The length of dormacy varies from state to state with Queensland and other warm states getting very little if any, to Tasmania and Victoria getting three months. As an example - A rose planted in late May in a cold climate will not break dormancy till Late August or early September.
If a cold snap is experienced for a considerable time then this may cause the sap to stop flowing on a plant and turn it dormant.