For rose aficionados and for gardeners who just take pleasure from growing roses it’s extremely frustrating when their own roses fail to bloom. Or, for that matter, when their own rose bushes fail to produce leaves. Something’s definitely up!
In areas where high humidity is common, botrytis blight can prove to be a problem for rose growers. It’s a common disease that impacts roses and lots of other plants. It’s caused by a fungus called Botrytis cinerea. And the onset of Botrytis cinerea can mean that rosebuds fail to open.
With improved air circulation in addition to various fungicidal sprays, it will certainly help to limit the impact of the blight, if not remove it altogether.
A further disease that can cause a lack of rose blooms is rose mosaic virus. This disease refers to a number of different viruses. For most parts of the U.S., a virus called Prunus necrotic ringspot virus is the main disease-causing pathogen. This pathogen may shorten the duration of rose blooms (or bring about zero blooms) and cause the rose bush to fail in producing leaves.
One of the most common rose pests that stops a rose bush from blooming is the root-knot nematode. The nematode sucks the juice of the root. In turn, because of the damage caused to the root system, the rose bush cannot absorb water and nutrients effectively enough. This leads to weak, stunted plants and few blooms if any at all.
Thrips can also cause serious overall damage to a rose bush. Particularly destructive in the U.S. are Florida flower thrips, western flower thrips, and chili thrips. All of these species feed on the leaves of the rose bush, as well as the buds and the flowers.
Two further rose plant predators are the rosebud borer and the large leaf-footed bug. Both of these eat rose blooms. This results in the malformation of flowers as well as a failure of buds opening.
All plants, as well as roses, require the appropriate nutrient balance so they can grow and develop in the right way.
With too much soil-based nitrogen and the plant can develop too much foliage – at the expense of the roots and the flowers.
With too little phosphorus, a nutrient that is completely essential for the development of flowers, and you’ll experience a lack of bloom production.
Soil nutrient imbalance can also cause a lack of leaves being produced.
Further signs of nutrient imbalance and deficiency include yellow leaves and stunted plant growth.
There are some organic fertilizers – alfalfa, cottonseed meal, as well as garden compost, can work to improve soil nutrient imbalance. So can commercial fertilizers of the ‘all-purpose’ kind.
Test your soil’s nutrient balance using a soil nutrient test kit.
Roses and Environmental Problems
Why aren’t my roses blooming?
A further reason that your roses are failing to bloom is down to some environmental factors. Examples of environmental factors? Cold weather, which can cause dead stems and thus, also dead flowers.
If you plant your roses in too much shade, the roses may suffer from something known as ‘rose blindness’.
Rose blindness means little to no production of buds.
For successful flower production on a rose bush, you need plenty of light.
Additionally, extreme heat and drought will stop rose bushes from producing blooms. Not much you can do about the heat but you can hand-water your roses if there’s drought and there’s no ban on water usage.
Incorrect Rose Care
For most varieties of roses, pruning is necessary. If rose bushes are not pruned they end up in a mess and there will be little production of flowers.
Don’t prune your roses too hard, though. If you do you can also ‘succumb’ to a lack of flowers on your rose bushes. Why so? Because the bush cannot produce enough photosynthetic energy to cater to the successful production of blooms.
When your roses are in bloom deadhead them regularly – at a minimum once weekly. This will remove the dead and in return, it encourages fresh blooming throughout the flowering season.