With the recent cooler temperatures, rose growth has slowed down. Some florists have noticed that the new buds of their roses are twisted or misshapen, what’s going on? During the critical period of rose germination in early spring, we need to pay special attention to a common problem – fertilizer damage in roses.
Causes of Fertilizer Damage
Early spring is the season when the new buds of roses sprout in large quantities, and the demand for fertilizer and water is high at this time. If there is insufficient fertilizer and water, the new buds of roses may become blind (i.e., branches that are unable to grow properly). Therefore, it is very important to apply water-soluble fertilizer in time to quickly replenish the nutrients when the new buds of roses are unfolding.
However, applying too high a concentration of fertilizer can lead to the phenomenon of fertilizer damage. Typical symptoms include:
- New leaves appear twisted and deformed
- Leaves appearing dark red in color
- In severe cases, leaf tips may appear blackened or scorched
If you notice any of these symptoms in your roses, you need to be vigilant – this is likely to be the result of fertilizer damage and prompt action is needed to save them.
Why does fertilizer damage happen?
Early spring is a time when roses are susceptible to fertilizer damage, and there may be several reasons for this:
- Excessive concentration of fertilizer: some florists do not properly proportion the concentration of fertilizer, resulting in fertilizer damage.
- Root health problems: Waterlogged potting soil in winter may lead to rotting roots, or root damage due to cold, which may affect the rose’s ability to absorb fertilizer.
- Varietal differences: Certain rose varieties are less tolerant of fertilizers and more susceptible to fertilizer damage.
Even when fertilizers are applied under the same conditions, individual plants may experience problems. This is precisely due to individual differences and varietal differences in fertilizer tolerance.
How to cope with fertilizer damage?
Scenario 1: Malformation of new leaves after the application of water-soluble fertilizers
If you find that the new leaves of roses are twisted or deformed after applying water-soluble fertilizers, it means that the concentration of the fertilizer is too high, and the roses are unable to fully absorb the metabolism. At this time, the following measures should be taken:
Suspend fertilizer application: Temporarily stop fertilizer application for one week to give roses a time to recover.
Irrigate the roots with fresh water: Dilute the concentration of fertilizer in the soil by pouring a large amount of fresh water to alleviate the fertilizer damage.
Observe new leaves: Normally, roses that are not severely fertilized will grow normal leaves.
Scenario 2: No water-soluble fertilizer has been applied but the new leaves are still deformed.
If no water-soluble fertilizer is applied, but the new shoots of early spring roses still appear deformed and twisted, then it may be due to the problem of bottom fertilizer.
When changing pots in winter, the bottom fertilizer is usually added. However, if the bottom fertilizer is not chosen properly, too much, or if the bottom fertilizer is in direct contact with the root system, it may lead to fertilizer damage. Since roses are dormant in winter, minor fertilizer damage may not be easily noticed until spring when new shoots are sprouted.
Solution:
If the new shoots are only slightly distorted, the fertilizer damage is mild and usually disappears with time.
If the new buds are seriously distorted, it is recommended to change the potting soil and reduce the amount of bottom fertilizer.
Note: Use of Foliar Fertilizer
In addition to rooting water-soluble fertilizer, spraying foliar fertilizer may also cause fertilizer damage. For example:
Fertilizer concentration is too high: when the concentration of foliar fertilizer is too high, irregular yellow scorched spots may appear on the leaves, and the yellow spots are usually scattered or merged to the edge or tip of the leaves.
Spraying too often: Over-spraying of foliar fertilizers can lead to similar problems.
If fertilizer damage occurs after spraying foliar fertilizers, it is recommended to:
- Stop using foliar fertilizer
- Appropriate spraying of water to clean the leaves
- Gradual recovery by the rose’s own growth metabolism